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Yates TA, Vijayakumar R, McGilvray M, Khiabani AJ, Razo N, Sinn L, Schill MR, Marrouche N, Zemlin C, Damiano RJ. Delayed-enhancement cardiac magnetic resonance imaging detects disease progression in patients with mitral valve disease and atrial fibrillation. JTCVS OPEN 2023; 16:292-302. [PMID: 38204711 PMCID: PMC10774962 DOI: 10.1016/j.xjon.2023.07.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 06/22/2023] [Accepted: 07/11/2023] [Indexed: 01/12/2024]
Abstract
Objectives The mechanism by which mitral valve (MV) disease leads to atrial fibrillation (AF) remains poorly understood. Delayed-enhancement cardiac magnetic resonance imaging (DE-MRI) has been used to assess left atrial (LA) fibrosis in patients with lone AF before catheter ablation; however, few studies have used DE-MRI to assess MV-induced LA fibrosis in patients with or without AF undergoing MV surgery. Methods Between March 2018 and September 2022, 38 subjects were enrolled; 15 age-matched controls, 14 patients with lone mitral regurgitation (MR), and 9 patients with MR and AF (MR + AF). Indexed LA volume, total LA wall, and regional LA posterior wall (LAPW) enhancement were defined by the DE-MRI. One-way analysis of variance was performed. Results LA volume and LA enhancement were associated (r = 0.451, P = .004). LA volume differed significantly between controls (37.1 ± 10.6 mL) and patients with lone MR (71.0 ± 35.9, P = .020 and controls and patients with MR + AF (99.3 ± 47.4, P < .001). The difference in LA enhancement was significant between MR + AF (16.7 ± 9.6%) versus controls (8.3 ± 3.9%, P = .006) and MR + AF versus lone MR (8.0 ± 4.8%, P = .004). Similarly, the was significantly more LAPW enhancement in the MR + AF (17.5 ± 8.7%) versus control (9.2 ± 5.1%, P = .011) and MR + AF versus lone MR (9.8 ± 6.0%, P = .020). Conclusions Patients with MR + AF had significantly more total and LAPW fibrosis compared with both controls and lone MR. Volume and delayed enhancement were associated, but there was no difference between MR and MR + AF.
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Affiliation(s)
- Tari-Ann Yates
- Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, Saint Louis, Mo
| | - Ramya Vijayakumar
- Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, Saint Louis, Mo
| | - Martha McGilvray
- Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, Saint Louis, Mo
| | - Ali J. Khiabani
- Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, Saint Louis, Mo
| | - Nicholas Razo
- Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, Saint Louis, Mo
| | - Laurie Sinn
- Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, Saint Louis, Mo
| | - Matthew R. Schill
- Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, Saint Louis, Mo
| | - Nassir Marrouche
- Department of Cardiology, Tulane University School of Medicine, New Orleans, La
| | - Christian Zemlin
- Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, Saint Louis, Mo
| | - Ralph J. Damiano
- Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, Saint Louis, Mo
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Ripplinger CM, Glukhov AV, Kay MW, Boukens BJ, Chiamvimonvat N, Delisle BP, Fabritz L, Hund TJ, Knollmann BC, Li N, Murray KT, Poelzing S, Quinn TA, Remme CA, Rentschler SL, Rose RA, Posnack NG. Guidelines for assessment of cardiac electrophysiology and arrhythmias in small animals. Am J Physiol Heart Circ Physiol 2022; 323:H1137-H1166. [PMID: 36269644 PMCID: PMC9678409 DOI: 10.1152/ajpheart.00439.2022] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/11/2022] [Accepted: 10/17/2022] [Indexed: 01/09/2023]
Abstract
Cardiac arrhythmias are a major cause of morbidity and mortality worldwide. Although recent advances in cell-based models, including human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM), are contributing to our understanding of electrophysiology and arrhythmia mechanisms, preclinical animal studies of cardiovascular disease remain a mainstay. Over the past several decades, animal models of cardiovascular disease have advanced our understanding of pathological remodeling, arrhythmia mechanisms, and drug effects and have led to major improvements in pacing and defibrillation therapies. There exist a variety of methodological approaches for the assessment of cardiac electrophysiology and a plethora of parameters may be assessed with each approach. This guidelines article will provide an overview of the strengths and limitations of several common techniques used to assess electrophysiology and arrhythmia mechanisms at the whole animal, whole heart, and tissue level with a focus on small animal models. We also define key electrophysiological parameters that should be assessed, along with their physiological underpinnings, and the best methods with which to assess these parameters.
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Affiliation(s)
- Crystal M Ripplinger
- Department of Pharmacology, University of California Davis School of Medicine, Davis, California
| | - Alexey V Glukhov
- Department of Medicine, Cardiovascular Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Matthew W Kay
- Department of Biomedical Engineering, The George Washington University, Washington, District of Columbia
| | - Bastiaan J Boukens
- Department Physiology, University Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
- Department of Medical Biology, University of Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Nipavan Chiamvimonvat
- Department of Pharmacology, University of California Davis School of Medicine, Davis, California
- Department of Internal Medicine, University of California Davis School of Medicine, Davis, California
- Veterans Affairs Northern California Healthcare System, Mather, California
| | - Brian P Delisle
- Department of Physiology, University of Kentucky, Lexington, Kentucky
| | - Larissa Fabritz
- University Center of Cardiovascular Science, University Heart and Vascular Center, University Hospital Hamburg-Eppendorf with DZHK Hamburg/Kiel/Luebeck, Germany
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Thomas J Hund
- Department of Internal Medicine, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
- Department of Biomedical Engineering, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Na Li
- Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Katherine T Murray
- Departments of Medicine and Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Steven Poelzing
- Virginia Tech Carilon School of Medicine, Center for Heart and Reparative Medicine Research, Fralin Biomedical Research Institute at Virginia Tech, Roanoke, Virginia
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - T Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
- School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Carol Ann Remme
- Department of Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands
| | - Stacey L Rentschler
- Cardiovascular Division, Department of Medicine, Washington University in Saint Louis, School of Medicine, Saint Louis, Missouri
| | - Robert A Rose
- Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Nikki G Posnack
- Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia
- Department of Pediatrics, George Washington University School of Medicine, Washington, District of Columbia
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3
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Abstract
The global burden caused by cardiovascular disease is substantial, with heart disease representing the most common cause of death around the world. There remains a need to develop better mechanistic models of cardiac function in order to combat this health concern. Heart rhythm disorders, or arrhythmias, are one particular type of disease which has been amenable to quantitative investigation. Here we review the application of quantitative methodologies to explore dynamical questions pertaining to arrhythmias. We begin by describing single-cell models of cardiac myocytes, from which two and three dimensional models can be constructed. Special focus is placed on results relating to pattern formation across these spatially-distributed systems, especially the formation of spiral waves of activation. Next, we discuss mechanisms which can lead to the initiation of arrhythmias, focusing on the dynamical state of spatially discordant alternans, and outline proposed mechanisms perpetuating arrhythmias such as fibrillation. We then review experimental and clinical results related to the spatio-temporal mapping of heart rhythm disorders. Finally, we describe treatment options for heart rhythm disorders and demonstrate how statistical physics tools can provide insights into the dynamics of heart rhythm disorders.
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Affiliation(s)
- Wouter-Jan Rappel
- Department of Physics, University of California San Diego, La Jolla, CA 92037
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4
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Rappel WJ, Krummen DE, Baykaner T, Zaman J, Donsky A, Swarup V, Miller JM, Narayan SM. Stochastic termination of spiral wave dynamics in cardiac tissue. FRONTIERS IN NETWORK PHYSIOLOGY 2022; 2:809532. [PMID: 36187938 PMCID: PMC9524168 DOI: 10.3389/fnetp.2022.809532] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Rotating spiral waves are self-organized features in spatially extended excitable media and may play an important role in cardiac arrhythmias including atrial fibrillation (AF). In homogeneous media, spiral wave dynamics are perpetuated through spiral wave breakup, leading to the continuous birth and death of spiral waves, but have a finite probability of termination. In non-homogeneous media, however, heterogeneities can act as anchoring sources that result in sustained spiral wave activity. It is thus unclear how and if AF may terminate following the removal of putative spiral wave sources in patients. Here, we address this question using computer simulations in which a stable spiral wave is trapped by an heterogeneity and is surrounded by spiral wave breakup. We show that, following ablation of spatial heterogeneity to render that region of the medium unexcitable, termination of spiral wave dynamics is stochastic and Poisson-distributed. Furthermore, we show that the dynamics can be accurately described by a master equation using birth and death rates. To validate these predictions in vivo, we mapped spiral wave activity in patients with AF and targeted the locations of spiral wave sources using radiofrequency ablation. Targeted ablation was indeed able to terminate AF, but only after a variable delay of up to several minutes. Furthermore, and consistent with numerical simulations, termination was not accompanied by gradual temporal or spatial organization. Our results suggest that spiral wave sources and tissue heterogeneities play a critical role in the maintenance of AF and that the removal of sources results in spiral wave dynamics with a finite termination time, which could have important clinical implications.
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Affiliation(s)
| | | | - Tina Baykaner
- Department of Medicine and Cardiovascular Institute, Stanford University, Palo Alto, California
| | - Junaid Zaman
- Department of Medicine, Division of Cardiology, University of Southern California, Los Angeles, California
| | | | - Vijay Swarup
- Arizona Heart Rhythm Institute, Phoenix, Arizona
| | - John M Miller
- Krannert Institute, Indiana University, Indianapolis, Indiana
| | - Sanjiv M Narayan
- Department of Medicine and Cardiovascular Institute, Stanford University, Palo Alto, California
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5
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Hartley A, Shalhoub J, Ng FS, Krahn AD, Laksman Z, Andrade JG, Deyell MW, Kanagaratnam P, Sikkel MB. Size matters in atrial fibrillation: the underestimated importance of reduction of contiguous electrical mass underlying the effectiveness of catheter ablation. Europace 2021; 23:1698-1707. [PMID: 33948648 PMCID: PMC8576280 DOI: 10.1093/europace/euab078] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 03/22/2021] [Indexed: 11/13/2022] Open
Abstract
Evidence has accumulated over the last century of the importance of a critical electrical mass in sustaining atrial fibrillation (AF). AF ablation certainly reduces electrically contiguous atrial mass, but this is not widely accepted to be an important part of its mechanism of action. In this article, we review data showing that atrial size is correlated in many settings with AF propensity. Larger mammals are more likely to exhibit AF. This is seen both in the natural world and in animal models, where it is much easier to create a goat model than a mouse model of AF, for example. This also extends to humans-athletes, taller people, and obese individuals all have large atria and are more likely to exhibit AF. Within an individual, risk factors such as hypertension, valvular disease and ischaemia can enlarge the atrium and increase the risk of AF. With respect to AF ablation, we explore how variations in ablation strategy and the relative effectiveness of these strategies may suggest that a reduction in electrical atrial mass is an important mechanism of action. We counter this with examples in which there is no doubt that mass reduction is less important than competing theories such as ganglionated plexus ablation. We conclude that, when considering future strategies for the ablative therapy of AF, it is important not to discount the possibility that contiguous electrical mass reduction is the most important mechanism despite the disappointing consequence being that enhancing success rates in AF ablation may involve greater tissue destruction.
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Affiliation(s)
- Adam Hartley
- National Heart and Lung Institute,Imperial College London, London, UK
| | - Joseph Shalhoub
- National Heart and Lung Institute,Imperial College London, London, UK
| | - Fu Siong Ng
- National Heart and Lung Institute,Imperial College London, London, UK
| | - Andrew D Krahn
- Division of Cardiology, University of British Columbia, 740 Hillside Ave, Vancouver, BC V8T 1Z4, Canada
| | - Zachary Laksman
- Division of Cardiology, University of British Columbia, 740 Hillside Ave, Vancouver, BC V8T 1Z4, Canada
| | - Jason G Andrade
- Division of Cardiology, University of British Columbia, 740 Hillside Ave, Vancouver, BC V8T 1Z4, Canada
| | - Marc W Deyell
- Division of Cardiology, University of British Columbia, 740 Hillside Ave, Vancouver, BC V8T 1Z4, Canada
| | | | - Markus B Sikkel
- Division of Cardiology, University of British Columbia, 740 Hillside Ave, Vancouver, BC V8T 1Z4, Canada
- Division of Medical Sciences, University of Victoria, Victoria, Canada
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6
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Denham NC, Pearman CM, Madders GWP, Smith CER, Trafford AW, Dibb KM. Optimising Large Animal Models of Sustained Atrial Fibrillation: Relevance of the Critical Mass Hypothesis. Front Physiol 2021; 12:690897. [PMID: 34211405 PMCID: PMC8239221 DOI: 10.3389/fphys.2021.690897] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 05/24/2021] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Large animal models play an important role in our understanding of the pathophysiology of atrial fibrillation (AF). Our aim was to determine whether prospectively collected baseline variables could predict the development of sustained AF in sheep, thereby reducing the number of animals required in future studies. Our hypothesis was that the relationship between atrial dimensions, refractory periods and conduction velocity (otherwise known as the critical mass hypothesis) could be used for the first time to predict the development of sustained AF. METHODS Healthy adult Welsh mountain sheep underwent a baseline electrophysiology study followed by implantation of a neurostimulator connected via an endocardial pacing lead to the right atrial appendage. The device was programmed to deliver intermittent 50 Hz bursts of 30 s duration over an 8-week period whilst sheep were monitored for AF. RESULTS Eighteen sheep completed the protocol, of which 28% developed sustained AF. Logistic regression analysis showed only fibrillation number (calculated using the critical mass hypothesis as the left atrial diameter divided by the product of atrial conduction velocity and effective refractory period) was associated with an increased likelihood of developing sustained AF (Ln Odds Ratio 26.1 [95% confidence intervals 0.2-52.0] p = 0.048). A receiver-operator characteristic curve showed this could be used to predict which sheep developed sustained AF (C-statistic 0.82 [95% confidence intervals 0.59-1.04] p = 0.04). CONCLUSION The critical mass hypothesis can be used to predict sustained AF in a tachypaced ovine model. These findings can be used to optimise the design of future studies involving large animals.
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Affiliation(s)
- Nathan C. Denham
- Unit of Cardiac Physiology, Institute of Cardiovascular Sciences, Manchester Academic Health Sciences Centre, The University of Manchester, Manchester, United Kingdom
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7
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van Staveren LN, de Groot NMS. Exploring Refractoriness as an Adjunctive Electrical Biomarker for Staging of Atrial Fibrillation. J Am Heart Assoc 2020; 9:e018427. [PMID: 33238778 PMCID: PMC7763798 DOI: 10.1161/jaha.120.018427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Patients diagnosed with the same subtype of atrial fibrillation according to our current classification system may differ in symptom severity, severity of the arrhythmogenic substrate, and response to antiarrhythmic therapy. Hence, there is a need for an electrical biomarker as an indicator of the arrhythmogenic substrate underlying atrial fibrillation enabling patient‐tailored therapy. The aim of this review is to investigate whether atrial refractoriness, a well‐known electrophysiological parameter that is affected by electrical remodeling, can be used as an electrical biomarker of the arrhythmogenic substrate underlying atrial fibrillation. We discuss methodologies of atrial effective refractory period assessment, identify which changes in refractoriness‐related parameters reflect different degrees of electrical remodeling, and explore whether these parameters can be used to predict clinical outcomes.
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8
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Mikhailov AV, Kalyanasundaram A, Li N, Scott SS, Artiga EJ, Subr MM, Zhao J, Hansen BJ, Hummel JD, Fedorov VV. Comprehensive evaluation of electrophysiological and 3D structural features of human atrial myocardium with insights on atrial fibrillation maintenance mechanisms. J Mol Cell Cardiol 2020; 151:56-71. [PMID: 33130148 DOI: 10.1016/j.yjmcc.2020.10.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/22/2020] [Accepted: 10/23/2020] [Indexed: 12/14/2022]
Abstract
Atrial fibrillation (AF) occurrence and maintenance is associated with progressive remodeling of electrophysiological (repolarization and conduction) and 3D structural (fibrosis, fiber orientations, and wall thickness) features of the human atria. Significant diversity in AF etiology leads to heterogeneous arrhythmogenic electrophysiological and structural substrates within the 3D structure of the human atria. Since current clinical methods have yet to fully resolve the patient-specific arrhythmogenic substrates, mechanism-based AF treatments remain underdeveloped. Here, we review current knowledge from in-vivo, ex-vivo, and in-vitro human heart studies, and discuss how these studies may provide new insights on the synergy of atrial electrophysiological and 3D structural features in AF maintenance. In-vitro studies on surgically acquired human atrial samples provide a great opportunity to study a wide spectrum of AF pathology, including functional changes in single-cell action potentials, ion channels, and gene/protein expression. However, limited size of the samples prevents evaluation of heterogeneous AF substrates and reentrant mechanisms. In contrast, coronary-perfused ex-vivo human hearts can be studied with state-of-the-art functional and structural technologies, such as high-resolution near-infrared optical mapping and contrast-enhanced MRI. These imaging modalities can resolve atrial arrhythmogenic substrates and their role in reentrant mechanisms maintaining AF and validate clinical approaches. Nonetheless, longitudinal studies are not feasible in explanted human hearts. As no approach is perfect, we suggest that combining the strengths of direct human atrial studies with high fidelity approaches available in the laboratory and in realistic patient-specific computer models would elucidate deeper knowledge of AF mechanisms. We propose that a comprehensive translational pipeline from ex-vivo human heart studies to longitudinal clinically relevant AF animal studies and finally to clinical trials is necessary to identify patient-specific arrhythmogenic substrates and develop novel AF treatments.
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Affiliation(s)
- Aleksei V Mikhailov
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Arrhythmology Research Department, Almazov National Medical Research Centre, Saint-Petersburg, Russia
| | - Anuradha Kalyanasundaram
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Ning Li
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Shane S Scott
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Esthela J Artiga
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Megan M Subr
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Jichao Zhao
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Brian J Hansen
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - John D Hummel
- Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Vadim V Fedorov
- Department of Physiology & Cell Biology, Bob and Corrine Frick Center for Heart Failure and Arrhythmia, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
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9
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Kim JH, Jang WS, Kim JB, Lee SJ. Impact of volume reduction in giant left atrium during surgical ablation of atrial fibrillation. J Thorac Dis 2019; 11:84-92. [PMID: 30863576 DOI: 10.21037/jtd.2018.12.118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background An enlarged left atrium (LA) is a well-known risk factor for ablation failure of atrial fibrillation (AF). We analyzed the result of concomitant AF ablation in patients with a giant LA and evaluated the effect of LA volume reduction. Methods Between 2000 and 2011, 116 patients with a giant LA (antero-posterior dimension ≥70 mm) who underwent surgical AF ablation during MV surgery were retrospectively reviewed. Among these, 28 patients received aggressive LA volume reduction procedure (reduction group) while the other 88 patients received the surgery without LA volume reduction (non-reduction group). Mean follow-up duration was 6.8±3.0 years. Results Aortic clamping and cardio-pulmonary bypass times were significantly longer in reduction group than non-reduction group (P<0.001 and 0.025, respectively). There were no significant differences in early mortality rates (3.7% vs. 5.7%, P>0.99) and major complication rates. Rates of freedom from AF at 1, 3 and 5 years were 84.2%, 74.3% and 54.5%, respectively in reduction group and 49.0%, 33.2% and 28.4%, respectively in non-reduction group (P=0.013). Multivariable analysis revealed severe pulmonary hypertension as an independent risk factor for AF recurrence (HR, 15.9; 95% CI, 1.69-149.54, P=0.015) while LA volume reduction (HR, 0.50; 95% CI, 0.28-0.89, P=0.018) and the use of cryoablation instead of radiofrequency (HR, 0.11; 95% CI, 0.01-0.95, P=0.045) were found to be protective against AF recurrence. Conclusions Aggressive LA volume reduction was found to improve rhythm outcomes in patients with a giant LA undergoing surgical AF ablation.
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Affiliation(s)
- Jae Hyun Kim
- Department of Thoracic and Cardiovascular Surgery, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea
| | - Woo Sung Jang
- Department of Thoracic and Cardiovascular Surgery, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea
| | - Jae-Bum Kim
- Department of Thoracic and Cardiovascular Surgery, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea
| | - Sook Jin Lee
- Department of Cardiology, Sejong Heart Institute, Sejong General Hospital, Bucheon, Republic of Korea
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10
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Abstract
Spatially extended excitable systems can exhibit spiral defect chaos (SDC) during which spiral waves continuously form and disappear. To address how this dynamical state terminates using simulations can be computationally challenging, especially for large systems. To circumvent this limitation, we treat the number of spiral waves as a stochastic population with a corresponding birth-death equation and use techniques from statistical physics to determine the mean episode duration of SDC. Motivated by cardiac fibrillation, during which the heart's electrical activity becomes disorganized and shows fragmenting spiral waves, we use generic models of cardiac electrophysiology. We show that the duration can be computed in minimal computational time and that it depends exponentially on domain size. Therefore, the approach can result in efficient and accurate predictions of mean episode duration which may be extended to more complex geometries and models.
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Affiliation(s)
- David Vidmar
- Department of Physics, University of California, San Diego, La Jolla, California 92093, USA
| | - Wouter-Jan Rappel
- Department of Physics, University of California, San Diego, La Jolla, California 92093, USA
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11
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Roney CH, Ng FS, Debney MT, Eichhorn C, Nachiappan A, Chowdhury RA, Qureshi NA, Cantwell CD, Tweedy JH, Niederer SA, Peters NS, Vigmond EJ. Determinants of new wavefront locations in cholinergic atrial fibrillation. Europace 2018; 20:iii3-iii15. [PMID: 30476057 PMCID: PMC6251188 DOI: 10.1093/europace/euy235] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 10/10/2018] [Indexed: 01/10/2023] Open
Abstract
AIMS Atrial fibrillation (AF) wavefront dynamics are complex and difficult to interpret, contributing to uncertainty about the mechanisms that maintain AF. We aimed to investigate the interplay between rotors, wavelets, and focal sources during fibrillation. METHODS AND RESULTS Arrhythmia wavefront dynamics were analysed for four optically mapped canine cholinergic AF preparations. A bilayer computer model was tuned to experimental preparations, and varied to have (i) fibrosis in both layers or the epicardium only, (ii) different spatial acetylcholine distributions, (iii) different intrinsic action potential duration between layers, and (iv) varied interlayer connectivity. Phase singularities (PSs) were identified and tracked over time to identify rotational drivers. New focal wavefronts were identified using phase contours. Phase singularity density and new wavefront locations were calculated during AF. There was a single dominant mechanism for sustaining AF in each of the preparations, either a rotational driver or repetitive new focal wavefronts. High-density PS sites existed preferentially around the pulmonary vein junctions. Three of the four preparations exhibited stable preferential sites of new wavefronts. Computational simulations predict that only a small number of connections are functionally important in sustaining AF, with new wavefront locations determined by the interplay between fibrosis distribution, acetylcholine concentration, and heterogeneity in repolarization within layers. CONCLUSION We were able to identify preferential sites of new wavefront initiation and rotational activity, in order to determine the mechanisms sustaining AF. Electrical measurements should be interpreted differently according to whether they are endocardial or epicardial recordings.
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Affiliation(s)
- Caroline H Roney
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
- LIRYC Electrophysiology and Heart Modeling Institute, Bordeaux Fondation, Avenue du Haut-Lévèque, Pessac, France
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Fu Siong Ng
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Michael T Debney
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Christian Eichhorn
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Arun Nachiappan
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Rasheda A Chowdhury
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Norman A Qureshi
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Chris D Cantwell
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Jennifer H Tweedy
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Steven A Niederer
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Nicholas S Peters
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Edward J Vigmond
- LIRYC Electrophysiology and Heart Modeling Institute, Bordeaux Fondation, Avenue du Haut-Lévèque, Pessac, France
- Univ. Bordeaux, IMB UMR 5251, F-33400 Talence, France
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When Is a Maze Procedure a Maze Procedure? Can J Cardiol 2018; 34:1482-1491. [DOI: 10.1016/j.cjca.2018.05.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 05/07/2018] [Accepted: 05/07/2018] [Indexed: 11/16/2022] Open
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Ruaengsri C, Schill MR, Lancaster TS, Khiabani AJ, Manghelli JL, Carter DI, Greenberg JW, Melby SJ, Schuessler RB, Damiano RJ. The hemodynamic and atrial electrophysiologic consequences of chronic left atrial volume overload in a controllable canine model. J Thorac Cardiovasc Surg 2018; 156:1871-1879.e1. [PMID: 30336917 DOI: 10.1016/j.jtcvs.2018.05.078] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 05/18/2018] [Accepted: 05/21/2018] [Indexed: 11/19/2022]
Abstract
OBJECTIVE The purpose of this study was to determine the effects of chronic left atrial volume overload on atrial anatomy, hemodynamics, and electrophysiology using a titratable left ventriculoatrial shunt in a canine model. METHODS Canines (n = 16) underwent implantation of a shunt between the left ventricle and the left atrium. Sham animals (n = 8) underwent a median sternotomy without a shunt. Atrial activation times and effective refractory periods were determined using 250-bipolar epicardial electrodes. Biatrial pressures, systemic pressures, left atrial and left ventricle diameters and volumes, atrial fibrillation inducibility, and durations were recorded at the initial and at 6-month terminal study. RESULTS Baseline shunt fraction was 46% ± 8%. The left atrial pressure increased from 9.7 ± 3.5 mm Hg to 13.8 ± 4 mm Hg (P < .001). At the terminal study, the left atrial diameter increased from a baseline of 2.9 ± 0.05 cm to 4.1 ± 0.6 cm (P < .001) and left ventricular ejection fraction decreased from 64% ± 1.5% to 54% ± 2.7% (P < .001). Induced atrial fibrillation duration (median, range) was 95 seconds (0-7200) compared with 0 seconds (0-40) in the sham group (P = .02). The total activation time was longer in the shunt group compared with the sham group (72 ± 11 ms vs 62 ± 3 ms, P = .003). The right atrial and not left atrial effective refractory periods were shorter in the shunt compared with the sham group (right atrial effective refractory period: 156 ± 11 ms vs 141 ± 11 ms, P = .005; left atrial effective refractory period: 142 ± 23 ms vs 133 ± 11 ms, P = .35). CONCLUSIONS This canine model of mitral regurgitation reproduced the mechanical and electrical remodeling seen in clinical mitral regurgitation. Left atrial size increased, with a corresponding decrease in left ventricle systolic function, and an increased atrial activation times, lower effective refractory periods, and increased atrial fibrillation inducibility. This model provides a means to understand the remodeling by which mitral regurgitation causes atrial fibrillation.
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Affiliation(s)
- Chawannuch Ruaengsri
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St Louis, Mo; Division of Cardiothoracic Surgery, Department of Surgery, Mahidol University, Ramathibodi Hospital, Bangkok, Thailand
| | - Matthew R Schill
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St Louis, Mo
| | - Timothy S Lancaster
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St Louis, Mo
| | - Ali J Khiabani
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St Louis, Mo
| | - Joshua L Manghelli
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St Louis, Mo
| | - Daniel I Carter
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St Louis, Mo
| | - Jason W Greenberg
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St Louis, Mo
| | - Spencer J Melby
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St Louis, Mo
| | - Richard B Schuessler
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St Louis, Mo
| | - Ralph J Damiano
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St Louis, Mo.
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14
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Ciaccio EJ, Peters NS, Garan H. Effects of refractory gradients and ablation on fibrillatory activity. Comput Biol Med 2018; 95:175-187. [PMID: 29501736 DOI: 10.1016/j.compbiomed.2018.02.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 02/18/2018] [Accepted: 02/21/2018] [Indexed: 10/18/2022]
Abstract
BACKGROUND The mechanisms involved in onset, maintenance, and termination of atrial fibrillation are not well understood. A biophysical model could be useful to determine how the events unfold. METHOD A two-dimensional cellular automaton consisting of 576 × 576 grid nodes was implemented to demonstrate the types of electrical activity that may occur in compromised atrial substrate. Electrical activation between nodes was made anisotropic (2:1), and the refractory period (RP) was adjusted from 74 to 192 ms in the spatial domain. Presence of collagen fibers were simulated as short lines of conduction block at many random grid sites, while ablation lesions were delineated as longer lines of block. An S1-S2 pulse from one grid corner was utilized to initiate simulated electrical activity. Simulations were done in which 1. no ablation lines, 2. random ablation lines, and 3. parallel ablation lines were added to the grid to determine how this affected the formation and annihilation of rotational activity after S1-S2 stimulation. RESULTS As the premature (S2) wavefront traversed the grid, rotational activity formed near boundaries where wavefronts propagated from shorter to longer refractory regions, causing unidirectional block, and were anchored by fiber clusters. Multiple wavelets appeared when wavefronts originating from different driving rotational features collided, and/or by their encounter with RP discontinuities. With the addition of randomly orientated simulated ablation lesions, followed by reinduction of fibrillatory activity, mean activation interval (AI) prolonged from a baseline level of 144.2 ms-160.3 ms (p < 0.001 in most comparisons). During fibrillatory activity, when parallel ablation lines were added to short RP regions, AI prolonged to 150.4 ms (p < 0.001), and when added to long RP regions, AI prolonged to 185.3 ms (p < 0.001). In all cases, AI prolongation after simulated ablation resulted from reduced number and/or from the isolation of local drivers, so that distant drivers in short RP regions activated long RP regions N:1, while distant drivers in long RP regions activated short RP regions at a relatively slow rate. CONCLUSIONS An automaton model was found useful to generate and test hypotheses concerning fibrillatory activity, which can then be validated in the clinical electrophysiology laboratory.
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Affiliation(s)
- Edward J Ciaccio
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, NY, United States; ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK.
| | - Nicholas S Peters
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London, UK
| | - Hasan Garan
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, NY, United States
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15
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Ma N, Wu XY, Ma CS, Liu N, Bai R, Du X, Ruan YF, Dong JZ. QTc interval predicts outcome of catheter ablation in paroxysmal atrial fibrillation patients with type 2 diabetes mellitus. JOURNAL OF HUAZHONG UNIVERSITY OF SCIENCE AND TECHNOLOGY. MEDICAL SCIENCES = HUA ZHONG KE JI DA XUE XUE BAO. YI XUE YING DE WEN BAN = HUAZHONG KEJI DAXUE XUEBAO. YIXUE YINGDEWEN BAN 2016; 36:646-652. [PMID: 27752887 DOI: 10.1007/s11596-016-1640-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 06/14/2016] [Indexed: 11/30/2022]
Abstract
Catheter ablation has been recommended as a treatment option for paroxysmal atrial fibrillation (PAF) patients complicated with type 2 diabetes mellitus (T2DM). PAF patients with T2DM have a higher recurrence rate after catheter ablation. Prolongation of corrected QT (QTc) interval has been linked to poor outcomes in T2DM patients. Whether the abnormal QTc interval is associated with the ablation outcome in the PAF patients with T2DM remains unknown. In this study, 134 PAF patients with T2DM undergoing primary catheter ablation were retrospectively enrolled. Pre-procedural QTc interval was corrected by using the Bazett's formula. Cox proportional hazards models were constructed to assess the relationship between QTc interval and the recurrence of AF. After a 29.1-month follow-up period, 61 patients experienced atrial tachyarrhythmia recurrence. Recurrent patients had a longer QTc interval than non-recurrent patients (425.2±21.5 ms vs. 414.1±13.4 ms, P=0.002). Multivariate Cox regression analysis revealed that QTc interval [hazard ratio (HR)=1.026, 95% confidence interval (CI) 1.012-1.040, P=0.005] and left atrial diameter (LAD) (HR=1.125, 95% CI 1.062-1.192, P=0.003) were independent predictors of recurrent atrial tachyarrhythmia. Receiver operating characteristic analysis demonstrated that the cut-off value of QTc (418 ms) predicted arrhythmia recurrence with a sensitivity of 55.7% and a specificity of 69.9%. A combination of LAD and QTc was more effective than LAD alone (P<0.001) in predicting arrhythmia recurrence after the procedure. QTc interval could be used as an independent predictor of arrhythmia recurrence in T2DM patients undergoing AF ablation, thus providing a simple method to identify those patients who likely have a better outcome following the procedure.
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Affiliation(s)
- Ning Ma
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China
| | - Xiao-Yan Wu
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China
| | - Chang-Sheng Ma
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China
| | - Nian Liu
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China
| | - Rong Bai
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China
| | - Xin Du
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China
| | - Yan-Fei Ruan
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China
| | - Jian-Zeng Dong
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China.
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Whitaker J, Rajani R, Chubb H, Gabrawi M, Varela M, Wright M, Niederer S, O'Neill MD. The role of myocardial wall thickness in atrial arrhythmogenesis. Europace 2016; 18:1758-1772. [PMID: 27247007 DOI: 10.1093/europace/euw014] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 01/13/2016] [Indexed: 01/08/2023] Open
Abstract
Changes in the structure and electrical behaviour of the left atrium are known to occur with conditions that predispose to atrial fibrillation (AF) and in response to prolonged periods of AF. We review the evidence that changes in myocardial thickness in the left atrium are an important part of this pathological remodelling process. Autopsy studies have demonstrated changes in the thickness of the atrial wall between patients with different clinical histories. Comparison of the reported tissue dimensions from pathological studies provides an indication of normal ranges for atrial wall thickness. Imaging studies, most commonly done using cardiac computed tomography, have demonstrated that these changes may be identified non-invasively. Experimental evidence using isolated tissue preparations, animal models of AF, and computer simulations proves that the three-dimensional tissue structure will be an important determinant of the electrical behaviour of atrial tissue. Accurately identifying the thickness of the atrial may have an important role in the non-invasive assessment of atrial structure. In combination with atrial tissue characterization, a comprehensive assessment of the atrial dimensions may allow prediction of atrial electrophysiological behaviour and in the future, guide radiofrequency delivery in regions based on their tissue thickness.
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Affiliation(s)
- John Whitaker
- Electrophysiology Division of Cardiovascular Directorate and Division of Imaging Sciences and Biomedical Engineering, King's College London, 4th Floor, North Wing, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK
| | - Ronak Rajani
- Department of Cardiac Computed Tomography, Cardiovascular Directorate, Guy's and St Thomas NHS Foundation Trust, London, UK
| | - Henry Chubb
- Electrophysiology Division of Cardiovascular Directorate and Division of Imaging Sciences and Biomedical Engineering, King's College London, 4th Floor, North Wing, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK.,Department of Paediatric Cardiology, Evelina London Children's Hospital, London, UK
| | - Mark Gabrawi
- Electrophysiology Division of Cardiovascular Directorate and Division of Imaging Sciences and Biomedical Engineering, King's College London, 4th Floor, North Wing, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK
| | - Marta Varela
- Electrophysiology Division of Cardiovascular Directorate and Division of Imaging Sciences and Biomedical Engineering, King's College London, 4th Floor, North Wing, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK
| | - Matthew Wright
- Electrophysiology Division of Cardiovascular Directorate and Division of Imaging Sciences and Biomedical Engineering, King's College London, 4th Floor, North Wing, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK
| | - Steven Niederer
- Electrophysiology Division of Cardiovascular Directorate and Division of Imaging Sciences and Biomedical Engineering, King's College London, 4th Floor, North Wing, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK
| | - Mark D O'Neill
- Electrophysiology Division of Cardiovascular Directorate and Division of Imaging Sciences and Biomedical Engineering, King's College London, 4th Floor, North Wing, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK
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17
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Barbhayia CR, Kumar S, Michaud GF. Mapping Atrial Fibrillation: 2015 Update. J Atr Fibrillation 2015; 8:1227. [PMID: 27957220 DOI: 10.4022/jafib.1227] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 08/11/2015] [Accepted: 08/16/2015] [Indexed: 12/19/2022]
Abstract
Atrial fibrillation requires a trigger that initiates the arrhythmia and substrate that favors perpetuation. Cardiac mapping is necessary to locate triggers and substrate so that an ablation strategy can be optimized. The most commonly used cardiac mapping approach is isochronal or activation mapping, which aims to create a spatial model of electrical wavefront propagation. Historically, activation mapping has been successful for mapping point source and single or double wave reentrant arrhythmias, while mapping multiple wavelets or driving sources that underlie most episodes of atrial fibrillation remains challenging. In the multiple wavelet model of AF there is no particular area critical to sustain atrial fibrillation, and a "critical mass" of atrium is required to maintain AF. Recent studies suggest endocardial and epicardial dissociation may play an important role. Investigation of driving sources that sustain AF has focused on the presence of rotors. Rotors in human AF have now been observed using multiple imaging modalities, however ablation strategies targeting rotors remain of unproven benefit. In addition, substrate mapping of AF is now feasible. Increasing degrees of atrial fibrosis on delayed enhancement magnetic resonance imaging (DE-MRI) has been shown to correlate with poor procedural outcomes for AF ablation, which suggests the increased burden of scar promotes more complex and extensive arrhythmia substrate. Atrial fibrosis is also identifiable using electrogram voltage tagging in an electro-anatomic mapping system. Patient-specific ablation strategies targeting areas of fibrosis are currently under investigation. Recent technological advances have facilitated greater understanding of the potential role for AF mapping and has allowed initiation of clinical studies to evaluate the effectiveness of mapping-based intervention. Multi-modality mapping is likely to play an increasingly important role in AF ablation, but is currently limited by the inability to simultaneously record and interpret electrical signals from both atria and from both the epicardium and endocardium.
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Affiliation(s)
| | - Saurabh Kumar
- Cardiovascular Division, Brigham and Women's Hospital, Boston, MA, USA
| | - Gregory F Michaud
- Cardiovascular Division, Brigham and Women's Hospital, Boston, MA, USA
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18
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Syed FF, Oral H. Electrophysiological Perspectives on Hybrid Ablation of Atrial Fibrillation. J Atr Fibrillation 2015; 8:1290. [PMID: 27957227 DOI: 10.4022/jafib.1290] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 10/05/2015] [Accepted: 12/14/2015] [Indexed: 12/14/2022]
Abstract
To overcome limitations of minimally invasive surgical ablation as a standalone procedure in eliminating atrial fibrillation (AF), hybrid approaches incorporating adjunctive endovascular catheter ablation have been proposed in recent years. The endovascular component targets residual conduction gaps and identifies additional electrophysiological targets with the goal of minimizing recurrent atrial arrhythmia. We performed a systematic review of published studies of hybrid AF ablation, analyzing 432 pooled patients (19% paroxysmal, 29% persistent, 52% long-standing persistent) treated using three different approaches: A. bilateral thoracoscopy with bipolar radiofrequency (RF) clamp-based approach; B. right thoracoscopic suction monopolar RF catheter-based approach; and C. subxiphoid posterior pericardioscopic ("convergent") approach. Freedom from recurrence off antiarrhythmic medications at 12 months was seen in 88.1% [133/151] for A, 73.4% [47/64] for B, and 59.3% [80/135] for C, with no significant difference between paroxysmal (76.9%) and persistent/long-standing persistent AF (73.4%). Death and major surgical complications were reported in 8.5% with A, 0% with B and 8.6% with C. A critical appraisal of hybrid ablation is presented, drawing from experiences and insights published over the years on catheter ablation of AF, with a discussion of the rationale underlying hybrid ablation, its strengths and limitations, where it may have a unique role in clinical management of patients with AF, which questions remain unanswered and areas for further investigation.
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Affiliation(s)
- Faisal F Syed
- Cardiac Arrhythmia Service, University of Michigan, Ann Arbor, MI
| | - Hakan Oral
- Cardiac Arrhythmia Service, University of Michigan, Ann Arbor, MI
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19
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Abstract
PURPOSE OF REVIEW Rotors have long been postulated to drive atrial fibrillation, but evidence has been limited to animal models. This changed recently with the demonstration using focal impulse and rotor modulation (FIRM) mapping that rotors act as human atrial fibrillation sources. This mechanistic approach to diagnosing the causes of atrial fibrillation in individual patients has been supported by substantially improved outcomes from FIRM-guided ablation, resulting in increased attention to rotors as therapeutic targets. RECENT FINDINGS In this review, we outline the pathophysiology of rotors in animal and in-silico studies of fibrillation, and how this motivated FIRM mapping in humans. We highlight the characteristics of rotors in human atrial fibrillation, now validated by several techniques, with discussion on similar and discrepant findings between techniques. The interventional approaches to eliminate atrial fibrillation rotors are explained and the ablation results in latest studies using FIRM are discussed. SUMMARY We propose that mapping localized sources for human atrial fibrillation, specifically rotors, is moving the field towards a unifying hypothesis that explains several otherwise contradictory observations in atrial fibrillation management. We conclude by suggesting areas of potential research that may reveal more about these critical sites and how these may lead to better and novel treatments for atrial fibrillation.
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20
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Carrick RT, Bates ORJ, Benson BE, Habel N, Bates JHT, Spector PS. Prospectively quantifying the propensity for atrial fibrillation: a mechanistic formulation. PLoS One 2015; 10:e0118746. [PMID: 25768978 PMCID: PMC4358999 DOI: 10.1371/journal.pone.0118746] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 01/16/2015] [Indexed: 11/18/2022] Open
Abstract
The goal of this study was to determine quantitative relationships between electrophysiologic parameters and the propensity of cardiac tissue to undergo atrial fibrillation. We used a computational model to simulate episodes of fibrillation, which we then characterized in terms of both their duration and the population dynamics of the electrical waves which drove them. Monte Carlo sampling revealed that episode durations followed an exponential decay distribution and wave population sizes followed a normal distribution. Half-lives of reentrant episodes increased exponentially with either increasing tissue area to boundary length ratio (A/BL) or decreasing action potential duration (APD), resistance (R) or capacitance (C). We found that the qualitative form of fibrillatory activity (e.g., multi-wavelet reentry (MWR) vs. rotors) was dependent on the ratio of resistance and capacitance to APD; MWR was reliably produced below a ratio of 0.18. We found that a composite of these electrophysiologic parameters, which we term the fibrillogenicity index (Fb = A/(BL*APD*R*C)), reliably predicted the duration of MWR episodes (r2 = 0.93). Given that some of the quantities comprising Fb are amenable to manipulation (via either pharmacologic treatment or catheter ablation), these findings provide a theoretical basis for the development of titrated therapies of atrial fibrillation.
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Affiliation(s)
- Richard T. Carrick
- Department of Bioengineering, University of Vermont College of Engineering and Mathematical Sciences, Burlington, Vermont, United States of America
| | - Oliver R. J. Bates
- Department of Biomedical Engineering, Boston University College of Engineering, Boston, Massachusetts, United States of America
| | - Bryce E. Benson
- Department of Bioengineering, University of Vermont College of Engineering and Mathematical Sciences, Burlington, Vermont, United States of America
| | - Nicole Habel
- Department of Medicine—Cardiology, University of Vermont College of Medicine, Burlington, Vermont, United States of America
| | - Jason H. T. Bates
- Department of Bioengineering, University of Vermont College of Engineering and Mathematical Sciences, Burlington, Vermont, United States of America
- Department of Medicine—Pulmonary Disease and Critical Care Medicine, University of Vermont College of Medicine, Burlington, Vermont, United States of America
| | - Peter S. Spector
- Department of Medicine—Cardiology, University of Vermont College of Medicine, Burlington, Vermont, United States of America
- * E-mail:
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Abstract
Isolation of the pulmonary veins may be an effective treatment modality for eliminating atrial fibrillation (AF) episodes but unfortunately not for all patients. When ablative therapy fails, it is assumed that AF has progressed from a trigger-driven to a substrate-mediated arrhythmia. The effect of radiofrequency ablation on persistent AF can be attributed to various mechanisms, including elimination of the trigger, modification of the arrhythmogenic substrate, interruption of crucial pathways of conduction, atrial debulking, or atrial denervation. This review discusses the possible effects of pulmonary vein isolation on the fibrillatory process and the necessity of cardiac mapping in order to comprehend the mechanisms of AF in the individual patient and to select the optimal treatment modality.
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Robertson JO, Saint LL, Leidenfrost JE, Damiano RJ. Illustrated techniques for performing the Cox-Maze IV procedure through a right mini-thoracotomy. Ann Cardiothorac Surg 2014; 3:105-16. [PMID: 24516807 DOI: 10.3978/j.issn.2225-319x.2013.12.11] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 12/28/2013] [Indexed: 11/14/2022]
Abstract
The Cox-Maze IV procedure has replaced the "cut-and-sew" technique of the original Cox-Maze operation with lines of ablation created using bipolar radiofrequency (RF) and cryothermal energy devices. In select patients, this procedure can be performed through a right mini-thoracotomy. This illustrated review is the first to detail the complete steps of the Cox-Maze IV procedure performed through a right mini-thoracotomy with careful attention paid to operative anatomy and advice. Pre- and post-operative management and outcomes are also discussed. This should be a practical guide for the practicing cardiac surgeon.
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Affiliation(s)
- Jason O Robertson
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, MO, USA
| | - Lindsey L Saint
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, MO, USA
| | - Jeremy E Leidenfrost
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, MO, USA
| | - Ralph J Damiano
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, MO, USA
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23
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Lawrance CP, Henn MC, Miller JR, Sinn LA, Schuessler RB, Damiano RJ. Comparison of the stand-alone Cox-Maze IV procedure to the concomitant Cox-Maze IV and mitral valve procedure for atrial fibrillation. Ann Cardiothorac Surg 2014; 3:55-61. [PMID: 24516798 DOI: 10.3978/j.issn.2225-319x.2013.12.09] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 12/26/2013] [Indexed: 11/14/2022]
Abstract
BACKGROUND The majority of patients undergoing surgical ablation for atrial fibrillation (AF) worldwide receive a concomitant mitral valve (MV) procedure. This study compared outcomes of the Cox-Maze IV (CMIV) in patients with lone AF to those with AF and MV disease. METHODS A retrospective review of 335 patients receiving either a stand-alone CMIV for AF (n=151) or a CMIV with a MV procedure (n=184) was performed from January 2002 through December of 2012. Data were obtained at 3, 6, 12, 24, and 48 months and patients were evaluated for recurrence of AF. Twenty-four preoperative and perioperative variables were evaluated to identify predictors of AF recurrence at one year. RESULTS The two groups differed in that stand-alone CMIV patients were younger, had AF of longer duration and had more failed catheter ablations, while patients with AF and MV disease had larger left atria and worse New York Heart Association class (P≤0.001). Operative mortality was higher in the concomitant MV group (1% vs. 5%, P=0.015). Freedom from AF and antiarrhythmic drugs at 12 and 24 months were similar between the two groups (73% and 76% at 12 months; 77% vs. 78% at 24 months). Predictors of recurrence included failure to use a box-lesion to isolate the pulmonary veins and posterior left atria, early recurrence of atrial tachyarrhythmias (ATAs) and the presence of a preoperative pacemaker (P=0.001). CONCLUSIONS The efficacy of the CMIV procedure was similar in patients with and without co-existent MV pathology. Patients receiving a concomitant CMIV and MV procedure represented an older and sicker patient population and had higher mortality rates than those receiving a stand-alone CMIV procedure.
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Affiliation(s)
- Christopher P Lawrance
- Department of Surgery, Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, MO, USA
| | - Matthew C Henn
- Department of Surgery, Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, MO, USA
| | - Jacob R Miller
- Department of Surgery, Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, MO, USA
| | - Laurie A Sinn
- Department of Surgery, Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, MO, USA
| | - Richard B Schuessler
- Department of Surgery, Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, MO, USA
| | - Ralph J Damiano
- Department of Surgery, Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, MO, USA
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DE Sisti A, Leclercq JF, Halimi F, Fiorello P, Bertrand C, Attuel P. Evaluation of time course and predicting factors of progression of paroxysmal or persistent atrial fibrillation to permanent atrial fibrillation. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2013; 37:345-55. [PMID: 24236932 DOI: 10.1111/pace.12264] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 07/07/2013] [Accepted: 08/04/2013] [Indexed: 01/24/2023]
Abstract
BACKGROUND To evaluate time course and predictors of progression of paroxysmal or persistent atrial fibrillation (AF) to permanent AF. METHODS AND RESULTS We included 460 patients referred for paroxysmal (n = 337) or persistent (n = 123) AF between 1994 and 2012. Mean follow-up was 13.2 ± 6.5 years. AF progression rate was 3.7% per year, 19.7% at 5 years, and 38.1% at 10 years. Lone AF was diagnosed in 217 patients (47%). Predictors of permanent AF were: age, persistent AF, left atrial (LA) size, left ventricular-fractional shortening (LV-FS), lack of antiarrhythmic (AA) drugs, VVI pacing (P < 0.001 for all), and valvular disease (P < 0.02). Independent predictors were age (P < 0.001), persistent AF (P < 0.001), LA diameter (P < 0.005), lack of AA drugs (P < 0.005), and VVI pacing (P < 0.01). When adjusted at means of covariates, persistent AF and age >75 years remained highly significant (P < 0.01). LA dimension >50 mm was highly significant at univariate model (P < 0.001) but to a lesser extent when adjusted (P < 0.05). In patients with paroxysmal AF-with age <75 years-on AA drugs, progression rate to permanent AF was 6.5% at 5 years and 23.7% at 10 years. Among four predictors (age, LA size, LV-FS, and VVI pacing), only age (P < 0.01) and LA size (P < 0.005) remained independently significant, but LA size was not significant when adjusted. CONCLUSIONS Progression to permanent AF is a slow process. Aging, LA size, VVI pacing, lack of AA therapy, and a persistent form of AF independently increased the progression to permanent AF.
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Affiliation(s)
- Antonio DE Sisti
- Rhythmology Department, Parly II Private Hospital, Le Chesnay, France; Rhythmology Unit, Clinique Paul Picquet, Sens, France
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Glukhov AV, Kalyanasundaram A, Lou Q, Hage LT, Hansen BJ, Belevych AE, Mohler PJ, Knollmann BC, Periasamy M, Györke S, Fedorov VV. Calsequestrin 2 deletion causes sinoatrial node dysfunction and atrial arrhythmias associated with altered sarcoplasmic reticulum calcium cycling and degenerative fibrosis within the mouse atrial pacemaker complex1. Eur Heart J 2013; 36:686-97. [PMID: 24216388 DOI: 10.1093/eurheartj/eht452] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
AIMS Loss-of-function mutations in Calsequestrin 2 (CASQ2) are associated with catecholaminergic polymorphic ventricular tachycardia (CPVT). CPVT patients also exhibit bradycardia and atrial arrhythmias for which the underlying mechanism remains unknown. We aimed to study the sinoatrial node (SAN) dysfunction due to loss of CASQ2. METHODS AND RESULTS In vivo electrocardiogram (ECG) monitoring, in vitro high-resolution optical mapping, confocal imaging of intracellular Ca(2+) cycling, and 3D atrial immunohistology were performed in wild-type (WT) and Casq2 null (Casq2(-/-)) mice. Casq2(-/-) mice exhibited bradycardia, SAN conduction abnormalities, and beat-to-beat heart rate variability due to enhanced atrial ectopic activity both at baseline and with autonomic stimulation. Loss of CASQ2 increased fibrosis within the pacemaker complex, depressed primary SAN activity, and conduction, but enhanced atrial ectopic activity and atrial fibrillation (AF) associated with macro- and micro-reentry during autonomic stimulation. In SAN myocytes, CASQ2 deficiency induced perturbations in intracellular Ca(2+) cycling, including abnormal Ca(2+) release, periods of significantly elevated diastolic Ca(2+) levels leading to pauses and unstable pacemaker rate. Importantly, Ca(2+) cycling dysfunction occurred not only at the SAN cellular level but was also globally manifested as an increased delay between action potential (AP) and Ca(2+) transient upstrokes throughout the atrial pacemaker complex. CONCLUSIONS Loss of CASQ2 causes abnormal sarcoplasmic reticulum Ca(2+) release and selective interstitial fibrosis in the atrial pacemaker complex, which disrupt SAN pacemaking but enhance latent pacemaker activity, create conduction abnormalities and increase susceptibility to AF. These functional and extensive structural alterations could contribute to SAN dysfunction as well as AF in CPVT patients.
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Affiliation(s)
- Alexey V Glukhov
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH, USA
| | - Anuradha Kalyanasundaram
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH, USA
| | - Qing Lou
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH, USA
| | - Lori T Hage
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH, USA
| | - Brian J Hansen
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH, USA
| | - Andriy E Belevych
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH, USA
| | - Peter J Mohler
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH, USA
| | - Björn C Knollmann
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Muthu Periasamy
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH, USA
| | - Sandor Györke
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH, USA
| | - Vadim V Fedorov
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH, USA
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Damiano RJ, Badhwar V, Acker MA, Veeragandham RS, Kress DC, Robertson JO, Sundt TM. The CURE-AF trial: a prospective, multicenter trial of irrigated radiofrequency ablation for the treatment of persistent atrial fibrillation during concomitant cardiac surgery. Heart Rhythm 2013; 11:39-45. [PMID: 24184028 DOI: 10.1016/j.hrthm.2013.10.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Ablation technology has been introduced to replace the surgical incisions of the Cox-Maze procedure in order to simplify the operation. However, the efficacy of these ablation devices has not been prospectively evaluated. OBJECTIVE The purpose of this study was to examine the efficacy and safety of irrigated unipolar and bipolar radiofrequency ablation for the treatment of persistent and long-standing persistent atrial fibrillation (AF) during concomitant cardiac surgical procedures. METHODS Between May 2007 and July 2011, 150 consecutive patients were enrolled at 15 U.S. centers. Patients were followed for 6 to 9 months, at which time a 24-hour Holter recording and echocardiogram were obtained. Recurrent AF was defined as any atrial tachyarrhythmia (ATA) lasting over 30 seconds on the Holter monitor. The safety end-point was the percent of patients who suffered a major adverse event within 30 days of surgery. All patients underwent a biatrial Cox-Maze lesion set. RESULTS Operative mortality was 4%, and there were 4 (3%) 30-day major adverse events. Overall freedom from ATAs was 66%, with 53% of patients free from ATAs and also off antiarrhythmic drugs at 6 to 9 months. Increased left atrial diameter, shorter total ablation time, and an increasing number of concomitant procedures were associated with recurrent AF (P <.05). CONCLUSION Irrigated radiofrequency ablation for treatment of AF during cardiac surgery was associated with a low complication rate. No device-related complications occurred. The Cox-Maze lesion set was effective at restoring sinus rhythm and had higher success rates in patients with smaller left atrial diameters and longer ablation times.
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Affiliation(s)
- Ralph J Damiano
- Division of Cardiothoracic Surgery, Washington University School of Medicine, St. Louis, Missouri.
| | - Vinay Badhwar
- Department of Cardiothoracic Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Michael A Acker
- Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - David C Kress
- Department of Cardiovascular and Thoracic Surgery, Aurora St. Luke's Medical Center, Milwaukee, Wisconsin
| | - Jason O Robertson
- Division of Cardiothoracic Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - Thoralf M Sundt
- Division of Cardiac Surgery, Massachusetts General Hospital, Boston, Massachusetts
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Mandyam MC, Soliman EZ, Alonso A, Dewland TA, Heckbert SR, Vittinghoff E, Cummings SR, Ellinor PT, Chaitman BR, Stocke K, Applegate WB, Arking DE, Butler J, Loehr LR, Magnani JW, Murphy RA, Satterfield S, Newman AB, Marcus GM. The QT interval and risk of incident atrial fibrillation. Heart Rhythm 2013; 10:1562-8. [PMID: 23872693 PMCID: PMC3787974 DOI: 10.1016/j.hrthm.2013.07.023] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Abnormal atrial repolarization is important in the development of atrial fibrillation (AF), but no direct measurement is available in clinical medicine. OBJECTIVE To determine whether the QT interval, a marker of ventricular repolarization, could be used to predict incident AF. METHODS We examined a prolonged QT interval corrected by using the Framingham formula (QT(Fram)) as a predictor of incident AF in the Atherosclerosis Risk in Communities (ARIC) study. The Cardiovascular Health Study (CHS) and Health, Aging, and Body Composition (ABC) study were used for validation. Secondary predictors included QT duration as a continuous variable, a short QT interval, and QT intervals corrected by using other formulas. RESULTS Among 14,538 ARIC study participants, a prolonged QT(Fram) predicted a roughly 2-fold increased risk of AF (hazard ratio [HR] 2.05; 95% confidence interval [CI] 1.42-2.96; P < .001). No substantive attenuation was observed after adjustment for age, race, sex, study center, body mass index, hypertension, diabetes, coronary disease, and heart failure. The findings were validated in Cardiovascular Health Study and Health, Aging, and Body Composition study and were similar across various QT correction methods. Also in the ARIC study, each 10-ms increase in QT(Fram) was associated with an increased unadjusted (HR 1.14; 95% CI 1.10-1.17; P < .001) and adjusted (HR 1.11; 95% CI 1.07-1.14; P < .001) risk of AF. Findings regarding a short QT interval were inconsistent across cohorts. CONCLUSIONS A prolonged QT interval is associated with an increased risk of incident AF.
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Affiliation(s)
- Mala C. Mandyam
- Div of Cardiology, Electrophysiology Sect, University of California, San Francisco
| | - Elsayed Z. Soliman
- Epidemiological Cardiology Research Center, Dept of Epidemiology and Prevention, Wake Forest University School of Medicine, Winston Salem, NC
| | - Alvaro Alonso
- Div of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis
| | - Thomas A. Dewland
- Div of Cardiology, Electrophysiology Sect, University of California, San Francisco
| | | | - Eric Vittinghoff
- Dept of Epidemiology and Biostatistics, University of California, San Francisco
| | | | - Patrick T. Ellinor
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown
| | | | - Karen Stocke
- ECG Core Laboratory, Saint Louis University School of Medicine, MO
| | - William B. Applegate
- Div of Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston Salem, NC
| | - Dan E. Arking
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD
| | - Javed Butler
- Cardiology Div, Dept of Medicine, Emory University, Atlanta, GA
| | - Laura R. Loehr
- Dept of Epidemiology, University of North Carolina at Chapel Hill
| | - Jared W. Magnani
- Dept of Medicine, Cardiovascular Medicine Section, Boston University, MA
| | - Rachel A. Murphy
- Laboratory of Population Science, Intramural Research Program, National Institute on Aging, Bethesda, MD
| | - Suzanne Satterfield
- Dept of Preventive Medicine, University of Tennessee Health Science Center, Memphis
| | - Anne B. Newman
- Dept of Epidemiology, School of Public Health, University of Pittsburgh, PA
| | - Gregory M. Marcus
- Div of Cardiology, Electrophysiology Sect, University of California, San Francisco
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Curnis A, Bisleri G, Bontempi L, Salghetti F, Cerini M, Lipari A, Pagnoni C, Vassanelli F, Muneretto C. Hybrid Therapy for Atrial Fibrillation: where the Knife meets the Catheter. J Atr Fibrillation 2013; 6:775. [PMID: 28496850 DOI: 10.4022/jafib.775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 03/18/2013] [Accepted: 03/28/2013] [Indexed: 11/10/2022]
Abstract
During the past decades there has been a consistent evolution of both surgical and catheter-based techniques for the treatment of stand-alone atrial fibrillation, as alternatives or in combination with anti-arrhythmic drugs. Transcatheter ablation has significantly improved outcomes, despite often requiring multiple procedures and with limited success rates especially in presence of persistent atrial fibrillation. Surgical procedures have dramatically evolved from the original cut-and-sew Maze operation, allowing nowadays for closed-chest epicardial ablations on the beating heart. Recently, the concept of a close collaboration between the cardiac surgeon and the electrophysiologist has emerged as an intriguing option in order to overcome the drawbacks and suboptimal results of both techniques; therefore, the hybrid approach has been proposed as a potentially more successful strategy, allowing for a patient-tailored therapeutical approach. We reviewed the recent advancements either from the transcatheter and surgical standpoint, with a peculiar focus on the current option to merge both techniques along with an up-to-date review of the preliminary clinical experiences with the hybrid, surgical-transcatheter treatment of stand-alone atrial fibrillation.
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Affiliation(s)
- Antonio Curnis
- Section of Electrophysiology, Division of Cardiology, Spedali Civili, University of Brescia Medical School, Brescia, Italy
| | - Gianluigi Bisleri
- Division of Cardiac Surgery, Spedali Civili, University of Brescia Medical School, Brescia, Italy
| | - Luca Bontempi
- Section of Electrophysiology, Division of Cardiology, Spedali Civili, University of Brescia Medical School, Brescia, Italy
| | - Francesca Salghetti
- Section of Electrophysiology, Division of Cardiology, Spedali Civili, University of Brescia Medical School, Brescia, Italy
| | - Manuel Cerini
- Section of Electrophysiology, Division of Cardiology, Spedali Civili, University of Brescia Medical School, Brescia, Italy
| | - Alessandro Lipari
- Section of Electrophysiology, Division of Cardiology, Spedali Civili, University of Brescia Medical School, Brescia, Italy
| | - Carlo Pagnoni
- Section of Electrophysiology, Division of Cardiology, Spedali Civili, University of Brescia Medical School, Brescia, Italy
| | - Francesca Vassanelli
- Section of Electrophysiology, Division of Cardiology, Spedali Civili, University of Brescia Medical School, Brescia, Italy
| | - Claudio Muneretto
- Division of Cardiac Surgery, Spedali Civili, University of Brescia Medical School, Brescia, Italy
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Tadic M, Ivanovic B, Cuspidi C. What do we currently know about metabolic syndrome and atrial fibrillation? Clin Cardiol 2013; 36:654-62. [PMID: 23788255 DOI: 10.1002/clc.22163] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 05/17/2013] [Indexed: 12/28/2022] Open
Abstract
Metabolic syndrome represents a cluster of atherogenic risk factors including hypertension, insulin resistance, obesity, and dyslipidemia. Considering that all of these risk factors could influence the development of atrial fibrillation, an association between atrial fibrillation and the metabolic syndrome has been suggested. Additionally, oxidative stress and inflammation have been involved in the pathogenesis of both metabolic syndrome and atrial fibrillation. The mechanisms that relate metabolic syndrome to the increased risk of atrial fibrillation occurrence are not completely understood. Metabolic syndrome and atrial fibrillation are associated with increased cardiovascular morbidity and mortality. Because atrial fibrillation is the most common arrhythmia, and along with the prevalence of metabolic syndrome constantly increasing, it would be very important to determine the relationship between these 2 entities, especially due to the fact that the risk factors of metabolic syndrome are mainly correctable. This review focused on the available evidence supporting the association between metabolic syndrome components and metabolic syndrome as a clinical entity with atrial fibrillation.
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Affiliation(s)
- Marijana Tadic
- Department of Cardiology, University Clinical Hospital Centre "Dr Dragisa Misovic" (Tadic), Belgrade, Serbia; Clinic of Cardiology (Ivanovic), Clinical Centre of Serbia, Belgrade, Serbia; Clinical Research Unit (Cuspidi), University of Milan-Bicocca and Istituto Auxologico Italiano, Meda, Italy
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Predictors and risk of pacemaker implantation after the Cox-maze IV procedure. Ann Thorac Surg 2013; 95:2015-20; disussion 2020-1. [PMID: 23642681 DOI: 10.1016/j.athoracsur.2013.03.064] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 03/19/2013] [Accepted: 03/22/2013] [Indexed: 01/10/2023]
Abstract
BACKGROUND The incidence of and causes for permanent pacemaker implantation (PPM) after surgical arrhythmia procedures remain poorly understood because of the varied lesion patterns and energy sources reported in small series. This study characterized the incidence, indications, and risk factors for PPM after the Cox-maze IV (CMIV) procedure when performed as either a lone or a concomitant procedure. METHODS A retrospective analysis of 340 patients undergoing a CMIV as either a lone (n = 112) or a concomitant (n = 228) procedure was conducted. The incidence, indication, and variables associated with PPM implantation within 1 year of the operation were assessed. Follow-up was conducted at 30 days and 1 year and was 90% complete. RESULTS The incidence of PPM after a lone CMIV procedure was 5%. Patients with concomitant cardiac operations had a nonsignificant increase in PPM insertion at 30 days (11% vs 5%, p = 0.14) and 1 year (15% vs 6%, p = 0.06) when compared with lone CMIV patients. Of patients who required pacemakers, sinus node dysfunction was present in 79% (35/44) of patients in the entire series and in 88% (8/9) after lone CMIV. After PPM, 84% (37/44) of patients remained paced at last follow-up. Multivariate analysis identified age (odds ratio = 1.10 [1.06-1.14], p < 0.001) as the only variable associated with higher risk of a PPM after any CMIV procedure. CONCLUSIONS The risk of PPM implantation after a lone CMIV is 5% and increases with age. The need for a PPM after a CMIV is largely due to SA node dysfunction, which appears unlikely to recover. These data should help physicians counsel patients regarding the perioperative risks associated with the CMIV.
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Lee AM, Aziz A, Didesch J, Clark KL, Schuessler RB, Damiano RJ. Importance of atrial surface area and refractory period in sustaining atrial fibrillation: testing the critical mass hypothesis. J Thorac Cardiovasc Surg 2012; 146:593-8. [PMID: 22995722 DOI: 10.1016/j.jtcvs.2012.04.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 03/20/2012] [Accepted: 04/06/2012] [Indexed: 11/29/2022]
Abstract
OBJECTIVE The critical mass hypothesis for atrial fibrillation (AF) was proposed in 1914; however, there have been few studies defining the relationship between atrial surface area and AF. This study evaluated the effect of tissue area and effective refractory period (ERP) on the probability of sustaining AF in an in vivo model. METHODS Domestic pigs (n = 9) underwent median sternotomy. Epicardial activation maps were constructed from bipolar electrograms recorded from form-fitting electrode templates placed on the atria. Baseline ERPs were determined. ERP was lowered with a continuous infusion of acetylcholine (0.005-0.04 mg/Kg/min) until AF could be sustained after burst pacing. The atria were sequentially partitioned using bipolar radiofrequency ablation. ERPs were lowered using acetylcholine until AF could be sustained in each subdivision of atrial tissue. Each subdivision was further divided until AF was no longer inducible. At study completion, the heart was excised and the surface area of each section was measured. RESULTS Over a range of ERPs from 75 to 250 ms, the probability of AF was correlated with increasing tissue area (range, 19.5-105 cm(2)) and decreasing ERP. Logistic regression analysis identified shorter ERP (P < .001) and larger area (P = .006) as factors predictive of an increased probability of sustained AF (area under the curve of the receiver-operator characteristic = 0.878). CONCLUSIONS The probability of sustained AF was significantly associated with increasing tissue area and decreasing ERP. These data may lead to a greater understanding of the mechanism of AF and help to design better interventional procedures.
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Affiliation(s)
- Anson M Lee
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, St Louis, Barnes-Jewish Hospital, St Louis, MO 63110, USA
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HWANG EUISEOCK, NAM GIBYUNG, JOUNG BOYOUNG, PARK JUNBEOM, LEE JIHEISARA, SHIM JAEMIN, UHM JAESUN, LEE MOONHYOUNG, PAK HUINAM. Significant Reduction of Atrial Defibrillation Threshold and Inducibility by Catheter Ablation of Atrial Fibrillation. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2012; 35:1428-35. [DOI: 10.1111/j.1540-8159.2012.03517.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Saint LL, Bailey MS, Prasad S, Guthrie TJ, Bell J, Moon MR, Lawton JS, Munfakh NA, Schuessler RB, Damiano RJ, Maniar HS. Cox-Maze IV results for patients with lone atrial fibrillation versus concomitant mitral disease. Ann Thorac Surg 2012; 93:789-94; discussion 794-5. [PMID: 22305055 DOI: 10.1016/j.athoracsur.2011.12.028] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 12/05/2011] [Accepted: 12/06/2011] [Indexed: 11/26/2022]
Abstract
BACKGROUND This study compared Cox-Maze IV (CMIV) outcomes for the treatment of atrial fibrillation (AF) in patients with lone AF vs those with AF and mitral valve (MV) disease. METHODS Since 2002, 200 patients have undergone a CMIV procedure for lone AF (n=101) or concomitantly with MV operations (n=99). Preoperative, perioperative, and late outcomes between these groups were compared. Data were collected prospectively and reported at 3, 6, and 12 months. RESULTS Lone AF patients had AF of longer duration; patients with AF and MV disease were older, with larger left atria and worse New York Heart Association classification (p<0.05). Operative mortality (1% vs 4%, p>0.05, respectively) was similar between both groups. Perioperative atrial tachyarrhythmias were more prevalent in patients with concomitant MV operations (57% vs 41%, p=0.03); however, freedom from AF and antiarrhythmics was similar for both groups at 12 months (76% and 77%). The only predictor for atrial tachyarrhythmia recurrence or arrhythmic drug dependence was failure to isolate the posterior left atrium (p<0.01). CONCLUSIONS Patients with AF and MV disease have distinct comorbidities compared with patients with lone AF. However, the CMIV is safe and effective in both groups and should be considered for patients with AF undergoing MV operations. Patients with MV disease had more atrial tachyarrhythmias at 3 months, but freedom from AF and antiarrhythmics was similar to patients with lone AF at 1 year. The posterior left atrium should be isolated in every patient, because this was the only predictor for failure of the CMIV for either group.
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Affiliation(s)
- Lindsey L Saint
- Washington University School of Medicine, Barnes-Jewish Hospital, Saint Louis, Missouri 63110, USA
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Harling L, Athanasiou T, Ashrafian H, Nowell J, Kourliouros A. Strategies in the surgical management of atrial fibrillation. Cardiol Res Pract 2011; 2011:439312. [PMID: 21747988 PMCID: PMC3130973 DOI: 10.4061/2011/439312] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 03/07/2011] [Accepted: 03/10/2011] [Indexed: 12/24/2022] Open
Abstract
Atrial fibrillation (AF) is associated with substantial morbidity, mortality, and economic burden and confers a lifetime risk of up to 25%. Current medical management involves thromboembolism prevention, rate, and rhythm control. An increased understanding of AF pathophysiology has led to enhanced pharmacological and medical therapies; however this is often limited by toxicity, variable symptom control, and inability to modulate the atrial substrate. Surgical AF ablation has been available since the original description of the Cox Maze procedure, either as a standalone or concomitant intervention. Advances in novel energy delivery systems have allowed the development of less technically demanding procedures potentially eliminating the need for median sternotomy and cardiopulmonary bypass. Variations in the definition, duration, and reporting of AF have produced methodological limitations impacting on the validity of interstudy comparisons. Standardization of these parameters may, in future, allow us to further evaluate clinical endpoints and establish the efficacy of these techniques.
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Affiliation(s)
- Leanne Harling
- Department of Surgery and Cancer, Imperial College London, London, W2 1NY, UK
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Damiano RJ, Schwartz FH, Bailey MS, Maniar HS, Munfakh NA, Moon MR, Schuessler RB. The Cox maze IV procedure: predictors of late recurrence. J Thorac Cardiovasc Surg 2011; 141:113-21. [PMID: 21168019 DOI: 10.1016/j.jtcvs.2010.08.067] [Citation(s) in RCA: 183] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 07/13/2010] [Accepted: 08/02/2010] [Indexed: 01/14/2023]
Abstract
OBJECTIVES The Cox maze III procedure achieved high cure rates and became the surgical gold standard for the treatment of atrial fibrillation. Because of its invasiveness, a more simplified ablation-assisted procedure, the Cox maze IV procedure, has been performed at our institution since January 2002. The study examined multiple preoperative and perioperative variables to determine predictors of late recurrence. METHODS Data were collected prospectively on 282 patients who underwent the Cox maze IV procedure from January 2002 through December 2009. Forty-two percent of patients had paroxysmal and 58% had either persistent or long-standing persistent atrial fibrillation. All patients were available for follow-up. Follow-up included electrocardiograms in all patients. Since 2006, 24-hour Holter monitoring was obtained in 94% of patients at 3, 6, and 12 months. Data were analyzed by means of logistic regression analysis at 12 months, with 13 preoperative and perioperative variables used as covariates. RESULTS Sixty-six percent of patients had a concomitant procedure. After an ablation-assisted Cox maze procedure, the freedom from atrial fibrillation was 89%, 93%, and 89% at 3, 6, and 12 months, respectively. The freedom from both atrial fibrillation and antiarrhythmic drugs was 63%, 79%, and 78% at 3, 6, and 12 months, respectively. The risk factors for atrial fibrillation recurrence at 1 year were enlarged left atrial diameter (P = .027), failure to isolate the entire posterior left atrium (P = .022), and early atrial tachyarrhythmias (P = .010). CONCLUSIONS The Cox maze IV procedure has a high success rate at 1 year, even with improved follow-up and stricter definitions of failure. In patients with large left atria, there might be a need for more extensive size reduction or expanded lesion sets.
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Affiliation(s)
- Ralph J Damiano
- Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, Saint Louis, Mo 63110, USA.
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Abstract
Atrial fibrillation (AF) is an emerging public health problem. The most important risk factor for developing chronic AF is uncontrolled hypertension. Uncontrolled hypertension promotes the initiation and perpetuation of AF through atrial remodeling. Experimental evidence has demonstrated the important role of the renin-angiotensin system in atrial remodeling. Retrospective analysis of several large clinical trials and small prospective trials suggests the beneficial role of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in preventing the onset and recurrence of AF in different populations. Several large prospective trials with longer follow-up periods are in progress. These trials may provide definitive evidence for the use of these agents in the prevention of AF.
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Osadchii OE, Olesen SP. Electrophysiological determinants of hypokalaemia-induced arrhythmogenicity in the guinea-pig heart. Acta Physiol (Oxf) 2009; 197:273-87. [PMID: 19656123 DOI: 10.1111/j.1748-1716.2009.02028.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM Hypokalaemia is an independent risk factor contributing to arrhythmic death in cardiac patients. In the present study, we explored the mechanisms of hypokalaemia-induced tachyarrhythmias by measuring ventricular refractoriness, spatial repolarization gradients, and ventricular conduction time in isolated, perfused guinea-pig heart preparations. METHODS Epicardial and endocardial monophasic action potentials from distinct left ventricular (LV) and right ventricular (RV) recording sites were monitored simultaneously with volume-conducted electrocardiogram (ECG) during steady-state pacing and following a premature extrastimulus application at progressively reducing coupling stimulation intervals in normokalaemic and hypokalaemic conditions. RESULTS Hypokalaemic perfusion (2.5 mm K(+) for 30 min) markedly increased the inducibility of tachyarrhythmias by programmed ventricular stimulation and rapid pacing, prolonged ventricular repolarization and shortened LV epicardial and endocardial effective refractory periods, thereby increasing the critical interval for LV re-excitation. Hypokalaemia increased the RV-to-LV transepicardial repolarization gradients but had no effect on transmural dispersion of APD(90) and refractoriness across the LV wall. As determined by local activation time recordings, the LV-to-RV transepicardial conduction and the LV transmural (epicardial-to-endocardial) conduction were slowed in hypokalaemic heart preparations. This change was attributed to depressed diastolic excitability as evidenced by increased ventricular pacing thresholds. CONCLUSION These findings suggest that hypokalaemia-induced arrhythmogenicity is attributed to shortened LV refractoriness, increased critical intervals for LV re-excitation, amplified RV-to-LV transepicardial repolarization gradients and slowed ventricular conduction in the guinea-pig heart.
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Affiliation(s)
- O E Osadchii
- Department of Biomedical Sciences, The Danish National Research Foundation Centre for Cardiac Arrhythmia, The Panum Institute, University of Copenhagen, Copenhagen N, Denmark.
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Chevalier P, Leizorovicz A, Maureira P, Carteaux JP, Corbineau H, Caus T, DeBreyne B, Mabot P, Dechillou C, Deharo JC, Barry S, Touboul P, Villemot JP, Obadia JF. Left atrial radiofrequency ablation during mitral valve surgery: a prospective randomized multicentre study (SAFIR). Arch Cardiovasc Dis 2009; 102:769-75. [PMID: 19944393 DOI: 10.1016/j.acvd.2009.08.010] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 07/05/2009] [Accepted: 08/21/2009] [Indexed: 12/15/2022]
Abstract
BACKGROUND Randomized studies evaluating left atrial radiofrequency ablation (RFA) in patients with persistent atrial fibrillation undergoing mitral valve surgery are scarce and monocentric. AIM To evaluate the efficacy of left atrial RFA concomitant with mitral valve surgery to restore and maintain sinus rhythm. METHODS The SAFIR is a multicentre, double-blinded, centrally randomized study involving four university hospitals. Between December 2002 and September 2005, 43 patients with mitral valve disease and long-standing, persistent atrial fibrillation (duration>6 months) were included. We compared valvular surgery alone (n=22) or with left atrial RFA (n=21). The main endpoint was sinus rhythm at 12 months without recurrence of arrhythmia during follow-up. Secondary endpoints were surgical adverse events, atrial fibrillation relapses, stroke and echocardiographic measurements after three and 12 months' follow-up. Analyses of the efficacy criteria were performed on an intention-to-treat basis. RESULTS The primary endpoint occurred significantly more often in the RFA group than in the control group (respectively, 12/21 patients [57%] vs 1/22 patients [4%]; p=0.004). There were more patients with sinus rhythm in the RFA group than in the control group at discharge (72.7% vs 4.8%; p<0.005), 3-month follow-up (85.7% vs 23.8%; p<0.01) and 12-month follow-up (95.2% vs 33.3%; p<0.005). The patients in the RFA group had similar rates of postoperative complications and stroke during follow-up as those in the control group. CONCLUSIONS This multicentre study suggests that left atrial RFA is effective and safe in patients with chronic atrial fibrillation and mitral valve disease.
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Affiliation(s)
- Philippe Chevalier
- Department of Cardiology/Rythmology, hospices civils de Lyon, hôpital cardiologique Louis-Pradel, CHU Louis-Pradel, avenue du Doyen-Lépine, Lyon cedex 03, France.
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Lee AM, Melby SJ, Damiano RJ. The surgical treatment of atrial fibrillation. Surg Clin North Am 2009; 89:1001-20, x-xi. [PMID: 19782848 DOI: 10.1016/j.suc.2009.06.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Atrial fibrillation is a complex disease affecting a significant portion of the general population. Although medical therapy is the mainstay of treatment, intervention plays an important role in selected patients. The Cox-Maze procedure is the gold standard for the surgical treatment of atrial fibrillation and has more than 90% success in eliminating atrial fibrillation. Ablation technologies have played a key role in simplifying this technically demanding procedure and making it available to more patients. A myriad of new lesion sets and approaches were introduced over the last decade which has made the operative treatment of atrial fibrillation less invasive and more confusing.
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Affiliation(s)
- Anson M Lee
- Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, 660 South Euclid, Campus Box 8234, St. Louis, MO 63110, USA
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Surgery for Lone Atrial Fibrillation: Present State-of-the-Art. INNOVATIONS-TECHNOLOGY AND TECHNIQUES IN CARDIOTHORACIC AND VASCULAR SURGERY 2009; 4:248-255. [PMID: 20473355 DOI: 10.1097/imi.0b013e3181bb370f] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
For two decades, the cut-and-sew Cox-Maze III procedure was the gold standard for the surgical treatment of atrial fibrillation (AF), and proved to be effective at curing lone AF and preventing its most dreaded complication, stroke. However, this procedure was not widely adopted due to its complexity and technical difficulty. Over the last 5-10 years, the introduction of new ablation technology has led to the development of the Cox-Maze IV procedure, as well as, more limited lesion sets, with the ultimate goal of performing a minimally-invasive lesion set on the beating heart, without the need for cardiopulmonary bypass. This review summarizes the current state of the art and future directions in the surgical treatment of lone atrial fibrillation. The hope is that as we learn more about the mechanisms of AF and develop preoperative diagnostic technologies capable of precisely locating the areas responsible for AF, it will become possible to tailor specific lesion sets and ablation modalities to individual patients, making the surgical treatment of lone AF available to a larger population of patients.
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Abstract
For two decades, the cut-and-sew Cox-maze III procedure was the gold standard for the surgical treatment of atrial fibrillation (AF) and has proven to be effective at eliminating AF. The incidence of late stroke was also very low. However, this procedure was not widely adopted owing to its complexity and technical difficulty. Over the last 5-10 years, the introduction of new ablation technology has led to the development of the Cox-maze IV procedure as well as more limited lesion sets, with the ultimate goal of performing a minimally invasive lesion set on the beating heart without the need for cardiopulmonary bypass. This review summarizes the current state of the art and future directions in the stand-alone surgical treatment of AF. The hope is that as more is learned about the mechanisms of AF and with better preoperative diagnostic technologies capable of precisely locating the areas responsible for AF, it will become possible to tailor specific lesion sets and ablation modalities to individual patients, making the surgical treatment of AF available to a larger population of patients.
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Affiliation(s)
- Jeanne Shen
- Washington University School of Medicine, Barnes-Jewish Hospital, Division of Cardiothoracic Surgery, Saint Louis, Missouri 63110, USA
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Oliveira M, da Silva MN, Timoteo AT, Feliciano J, Sousa L, Santos S, Silva-Carvalho L, Ferreira R. Inducibility of atrial fibrillation during electrophysiologic evaluation is associated with increased dispersion of atrial refractoriness. Int J Cardiol 2008; 136:130-5. [PMID: 18676037 DOI: 10.1016/j.ijcard.2008.04.097] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Revised: 03/20/2008] [Accepted: 04/23/2008] [Indexed: 11/26/2022]
Abstract
UNLABELLED The impact of atrial dispersion of refractoriness (Disp_A) in the inducibility and maintenance of atrial fibrillation (AF) has not been fully resolved. AIM To study the Disp_A and the vulnerability (A_Vuln) for the induction of self-limited (<60 s) and sustained episodes of AF. METHODS AND RESULTS Forty-seven patients with paroxysmal AF (PAF): 29 patients without structural heart disease and 18 with hypertensive heart disease. Atrial effective refractory period (ERP) was assessed at five sites--right atrial appendage and low lateral right atrium, high interatrial septum, proximal and distal coronary sinus. We compared three groups: group A - AF not inducible (n=13); group B - AF inducible, self-limited (n=18); group C - AF inducible, sustained (n=16). Age, lone AF, hypertension, left atrial and left ventricular (LV) dimensions, LV systolic function, duration of AF history, atrial flutter/tachycardia, previous antiarrhythmics, and Disp_A were analysed with logistic regression to determine association with A_Vuln for AF inducibility. The ERP at different sites showed no differences among the groups. Group A had a lower Disp_A compared to group B (47+/-20 ms vs 82+/-65 ms; p=0.002), and when compared to group C (47+/-20 ms vs 80+/-55 ms; p=0.008). There was no significant difference in Disp_A between groups B and C. By means of multivariate regression analysis, the only predictor of A_Vuln was Disp_A (p=0.04). CONCLUSION In patients with PAF, increased Disp_A represents an electrophysiological marker of A_Vuln. Inducibility of both self-limited and sustained episodes of AF is associated with similar values of Disp_A. These findings suggest that the maintenance of AF is influenced by additional factors.
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Affiliation(s)
- Mario Oliveira
- Cardiology Department, Santa Marta Hospital, Lisbon, Portugal
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Melby SJ, Lee AM, Zierer A, Kaiser SP, Livhits MJ, Boineau JP, Schuessler RB, Damiano RJ. Atrial fibrillation propagates through gaps in ablation lines: implications for ablative treatment of atrial fibrillation. Heart Rhythm 2008; 5:1296-301. [PMID: 18774106 DOI: 10.1016/j.hrthm.2008.06.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2006] [Accepted: 06/07/2008] [Indexed: 11/29/2022]
Abstract
BACKGROUND It has been hypothesized that atrial lesions must be transmural to successfully cure atrial fibrillation (AF). However, ablation lines often do not extend completely across the atrial wall. OBJECTIVE The purpose of this study was to determine the effect of residual gaps on conduction properties of atrial tissue. METHODS Canine right atria (n = 13) were isolated, perfused, and mounted on a 250-lead electrode plaque. The atria were divided with a bipolar radiofrequency ablation clamp, leaving a gap that was progressively narrowed. Conduction velocities at varying pacing rates and AF frequencies were measured before and after ablations. AF was induced with an extra stimulus and acetylcholine. RESULTS Gap widths from 11.2 to 1.1 mm were examined. Conduction velocities through gaps were dependent cycle length (P = .002) and gap size (P <.001). Overall, 253 (97%) of a total of 260 gaps allowed paced propagation; 51 (91%) of 56 gaps 1-3 mm in width permitted paced propagation, as did 202 (99%) of 204 gaps >or=3.0 mm. Similarly, 253 (97%) of a total of 260 gaps allowed propagation of AF. For AF, 51 (93%) of 55 gaps 1-3 mm allowed AF to pass through, as did 202 (99%) of 205 gaps >or=3.0 mm. Gaps as small as 1.1 mm conducted paced and AF impulses. CONCLUSIONS Conduction velocities were slowed through residual gaps. However, propagation of wave fronts during pacing and AF occurred through the majority of residual gaps, down to sizes as small as 1.1 mm. Leaving viable tissue in ablation lines for the treatment of AF could account for failures.
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Affiliation(s)
- Spencer J Melby
- Department of Surgery, Division of Cardiothoracic Surgery, Washington University in St. Louis School of Medicine and Barnes Jewish Hospital, St. Louis, Missouri 63110, USA
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Petrutiu S, Sahakian AV, Swiryn S. Abrupt changes in fibrillatory wave characteristics at the termination of paroxysmal atrial fibrillation in humans. Europace 2007; 9:466-70. [PMID: 17540663 DOI: 10.1093/europace/eum096] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS We investigated the process of spontaneous termination of atrial fibrillation (AF) to determine its time course from the surface ECG. METHODS AND RESULTS We studied fibrillatory waves in Holter recordings of paroxysmal and sustained AF. Following QRS-T cancellation dominant frequencies (DFs) were computed and the relationship of DF to termination was scrutinized. For 57 episodes of paroxysmal AF (PAF) in 24 patients, DF ranged from 4.4 to 6.5 Hz (5.2 +/- 0.4 Hz) compared to 5.8 to 7.4 Hz (6.6 +/- 0.6 Hz) for sustained AF recordings. Comparison of the atrial frequency of the ultimate to the penultimate second demonstrated a drop in frequency in 51 of 57 episodes, P < 0.00001. No comparable change was seen at longer time periods. Moments of comparably low frequency without termination were only occasionally seen in patients with PAF but not in patients with sustained AF. CONCLUSION Low frequency fibrillation was found to be much more likely to terminate. Frequency changes preceding spontaneous termination were abrupt, in contrast to the gradual frequency drop reported with drug-induced termination. The analysis of fibrillatory wave characteristics and their change over time might be used to target specific moments for pacing therapy in patients with AF.
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Affiliation(s)
- Simona Petrutiu
- Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL, USA
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Yang Y, Liu Y, Dong X, Kuang Y, Lin J, Su X, Peng L, Jin Q, He Y, Liu B, Pan Z, Li L, Zhu Q, Lin X, Zhou Q, Pan Q, Eurlings PMH, Fei J, Wang Z, Chen YH. Human KCNQ1 S140G mutation is associated with atrioventricular blocks. Heart Rhythm 2007; 4:611-8. [PMID: 17467630 DOI: 10.1016/j.hrthm.2007.01.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2006] [Accepted: 01/22/2007] [Indexed: 11/24/2022]
Abstract
BACKGROUND We recently reported that an S140G mutation in human KCNQ1, an alpha subunit of potassium channels, was involved in the pathogenesis of familial atrial fibrillation (AF), but it is not clear whether the mutation is associated with other cardiac arrhythmias. OBJECTIVE The purpose of this study was to further explore the association of the KCNQ1 S140G mutation with cardiac arrhythmias. METHODS We produced a transgenic mouse model with myocardium-specific expression of the human KCNQ1 S140G mutation under the control of an alpha-cardiac myosin heavy chain promoter by standard transgenic procedure and evaluated the relationship between the KCNQ1 mutation and its phenotypes in a human family. RESULTS Four lines of transgenic mice were established with a high level of human KCNQ1 S140G expression in the heart. Frequent episodes of first-, second-, advanced-, or third-degree atrioventricular block (AVB) occurred in at least 65% of transgenic descendants from the four lines. However, none of the five wild-type transgenic lines presented with AVBs. HMR1556, a KCNQ1-specific blocker, can terminate the AVBs. With the exception of at most three AF individuals, at least 13 AF patients were found to show obviously slow ventricular response, which may be one manifestation of AVBs. Interestingly, AF was not detected in these transgenic mice. CONCLUSION The results suggest that human KCNQ1 S140G is also likely to be a causative mutation responsible for AVBs. The transgenic mouse model is a potential tool to explore mechanisms of AVBs.
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Affiliation(s)
- Yiqing Yang
- Department of Cardiology, Tongji Hospital, Shanghai, China
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