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Younis A, Nehoray N, Glikson M, Bodurian C, Nof E, Bragazzi NL, Berger M, Zareba W, Goldenberg I, Beinart R. QTc Dynamics Following Cardioversion for Persistent Atrial Fibrillation. Front Cardiovasc Med 2022; 9:881446. [PMID: 35722129 PMCID: PMC9205203 DOI: 10.3389/fcvm.2022.881446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 05/11/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundCardioversion (CV) for atrial fibrillation (AF) is common. We aimed to assess changes in QTc over time following electrical CV (ECV) for persistent AF, and to compare the benefit of using continuous Holter monitoring vs. conventional follow-up by ECG.MethodsProspective observational cohort study. We comprised 90 patients admitted to our center for elective ECV due to persistent AF who were prospectively enrolled from July 2017 to August 2018. All patients underwent 7-days Holter started prior to ECV. Baseline QTc was defined as median QTc during 1 h post ECV. The primary endpoint was QTc prolongation defined as QTc ≥500 ms, or ≥10% increase (if baseline QTc was >480 ms). Conventional monitoring was defined as 2-h ECG post ECV.ResultsMean age was 67 ± 11 years and 61% were male. Median baseline QTc was 452 ms (IQ range: 431–479 ms) as compared with a maximal median QTc of 474 ms (IQ range: 433–527 ms; p <0.001 for the change in QTc from baseline). Peak median QTc occurred 44 h post ECV. The primary endpoint was met in 3 patients (3%) using conventional monitoring, compared with 39 new patients (43%) using Holter (p <0.001 for comparison). The Holter monitoring was superior to conventional monitoring in detecting clinically significant QTc prolongation (OR = 13; p <0.001).ConclusionsECV of patients with persistent AF was associated with increased transient risk of QTc prolongation in nearly half of the patients. Peak median QTc occurs during end of second day following ECV and prolonged ECG monitoring provides superior detection of significant QTc prolongation compared with conventional monitoring.
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Affiliation(s)
- Arwa Younis
- Cardiac Electrophysiology and Pacing Section, Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, OH, United States
- *Correspondence: Arwa Younis ; orcid.org/0000-0002-2485-5025
| | - Nofrat Nehoray
- Chaim Sheba Medical Center Affiliated to Sackler Medical School, Tel Aviv University, Ramat Gan, Israel
| | - Michael Glikson
- Heart Center, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Christopher Bodurian
- Clinical Cardiovascular Research Center, University of Rochester, Rochester, NY, United States
| | - Eyal Nof
- Chaim Sheba Medical Center Affiliated to Sackler Medical School, Tel Aviv University, Ramat Gan, Israel
| | - Nicola Luigi Bragazzi
- Laboratory for Industrial and Applied Mathematics, Center for Disease Modeling, York University, Toronto, ON, Canada
| | - Michael Berger
- Chaim Sheba Medical Center Affiliated to Sackler Medical School, Tel Aviv University, Ramat Gan, Israel
| | - Wojciech Zareba
- Clinical Cardiovascular Research Center, University of Rochester, Rochester, NY, United States
| | - Ilan Goldenberg
- Clinical Cardiovascular Research Center, University of Rochester, Rochester, NY, United States
| | - Roy Beinart
- Chaim Sheba Medical Center Affiliated to Sackler Medical School, Tel Aviv University, Ramat Gan, Israel
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Khan ZA, LaBreck ME, Luli J, Roberts C, Smith A, El-Zein R, Tyler JD, Fu EY, Billakanty SR, Amin AK, Chopra N. Longitudinal QT c Stability and Impact of Baseline Cardiac Rhythm on Discharge Dose in Dofetilide-treated Patients. J Cardiovasc Electrophysiol 2022; 33:1281-1289. [PMID: 35362175 DOI: 10.1111/jce.15483] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 03/03/2022] [Accepted: 03/30/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND Dofetilide suppresses AF in a dose-dependent fashion. The protective effect of AF against QTc prolongation induced torsades de pointe and transient post-cardioversion QTc prolongation may result in dofetilide under-dosing during initiation. Thus, the optimal timing of cardioversion for AF patients undergoing dofetilide initiation to optimize discharge dose remains unknown as does the longitudinal stability of QTc . OBJECTIVE To evaluate the impact of baseline rhythm on dofetilide dosing during initiation and assess the longitudinal stability of QTc-all (Bazzett, Fridericia, Framingham, and Hodges) over time. METHODS Medical records of patients who underwent pre-planned dofetilide loading at a tertiary care center between January 2016-2019 were reviewed. RESULTS A total of 198 patients (66±10 years, 32% female, CHADS2 -Vasc 3 [2-4]) presented for dofetilide loading in either AF (59%) or SR (41%). Neither presenting rhythm, nor spontaneous conversion to SR impacted discharge dose. The cumulative dofetilide dose prior to cardioversion moderately correlated (r=0.36; p=0.0001) with discharge dose. Post-cardioversion QTc-all prolongation (p<0.0001) prompted discharge dose reduction (890±224mcg vs 552±199mcg; p<0.0001) in 30% patients. QTc-all in SR prolonged significantly during loading (p<0.0001). All patients displayed QTc-all reduction (p<0.0001) from discharge to short-term (46 [34-65] days) that continued at long-term (360 [296-414] days) follow-ups. The extent of QTc-all reduction over time moderately correlated with discharge QTc-all (r=0.54-0.65; p<0.0001). CONCLUSION Dofetilide initiation prior to cardioversion is equivalent to initiation during SR. Significant QTc reduction proportional to discharge QTc is seen over time in all dofetilide-treated patients. QTc returns to pre-loading baseline during follow-up in patients initiated in SR. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Zeryab A Khan
- Department of Internal Medicine, OhioHealth Doctors Hospital, 5100 West Broad Street Columbus, OH, 43228
| | - Megan E LaBreck
- Department of Pharmacy, Riverside Methodist Hospital, 3535 Olentangy River Road, Columbus, OH, 43214
| | - Jordan Luli
- Department of Internal Medicine, OhioHealth Doctors Hospital, 5100 West Broad Street Columbus, OH, 43228
| | - Chelsea Roberts
- Department of Pharmacy, Riverside Methodist Hospital, 3535 Olentangy River Road, Columbus, OH, 43214
| | - Alexander Smith
- Department of Internal Medicine, Riverside Methodist Hospital, 3535 Olentangy River Road, Columbus, OH, 43214, USA
| | - Rayan El-Zein
- Department of Internal Medicine, OhioHealth Doctors Hospital, 5100 West Broad Street Columbus, OH, 43228
| | - Jaret D Tyler
- Section of Cardiac Electrophysiology, Department of Cardiology, OhioHealth Heart and Vascular Physicians, Riverside Methodist Hospital, 3535 Olentangy River Road, Columbus, OH, 43214, USA
| | - Eugene Y Fu
- Section of Cardiac Electrophysiology, Department of Cardiology, OhioHealth Heart and Vascular Physicians, Riverside Methodist Hospital, 3535 Olentangy River Road, Columbus, OH, 43214, USA
| | - Sreedhar R Billakanty
- Section of Cardiac Electrophysiology, Department of Cardiology, OhioHealth Heart and Vascular Physicians, Riverside Methodist Hospital, 3535 Olentangy River Road, Columbus, OH, 43214, USA
| | - Anish K Amin
- Section of Cardiac Electrophysiology, Department of Cardiology, OhioHealth Heart and Vascular Physicians, Riverside Methodist Hospital, 3535 Olentangy River Road, Columbus, OH, 43214, USA
| | - Nagesh Chopra
- Section of Cardiac Electrophysiology, Department of Cardiology, OhioHealth Heart and Vascular Physicians, Riverside Methodist Hospital, 3535 Olentangy River Road, Columbus, OH, 43214, USA
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Lypourlis D, Mundisugih J, Chia YV. EARLY AFTERDEPOLARISTATIONS AND ELECTRICAL STORM AFTER CARIDIOVERSION FOR ATRIAL FIBRILLATION. HeartRhythm Case Rep 2022; 8:254-258. [PMID: 35497487 PMCID: PMC9039098 DOI: 10.1016/j.hrcr.2022.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
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Chikata A, Kato T, Usuda K, Fujita S, Otowa KI, Maruyama M, Hayashi K, Takamura M. Torsade de Pointes Due to QT Prolongation after Pulmonary Vein Isolation for Persistent Atrial Fibrillation. Intern Med 2021; 60:2089-2092. [PMID: 33518578 PMCID: PMC8313932 DOI: 10.2169/internalmedicine.6627-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We herein report a 60-year-old woman with long-standing persistent atrial fibrillation (AF) who developed QT prolongation and torsade de pointes (TdP) after pulmonary vein isolation (PVI). When electrical cardioversion was performed three months before PVI, prominent QT prolongation was not observed. QT prolongation emerged after PVI and was sustained until AF recurrence on the third day after ablation, and TdP disappeared along with AF recurrence. PVI affects the ganglionated plexi around the atrium, leading to modification of the intrinsic cardiac autonomic system. This case indicates that PVI has the potential risk of inducing lethal ventricular arrhythmias due to QT prolongation.
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Affiliation(s)
- Akio Chikata
- Department of Cardiology, Toyama Prefectural Central Hospital, Japan
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Science, Japan
| | - Takeshi Kato
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Science, Japan
| | - Kazuo Usuda
- Department of Cardiology, Toyama Prefectural Central Hospital, Japan
| | - Shuhei Fujita
- Department of Pediatrics, Toyama Prefectural Central Hospital, Japan
| | - Kan-Ichi Otowa
- Department of Cardiology, Toyama Prefectural Central Hospital, Japan
| | - Michiro Maruyama
- Department of Cardiology, Toyama Prefectural Central Hospital, Japan
| | - Kenshi Hayashi
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Science, Japan
| | - Masayuki Takamura
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Science, Japan
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Riddle M, McCallum R, Ojha CP, Paul TK, Gupta V, Baran DA, Prakash BV, Misra A, Mares AC, Abedin M, Kedar A, Mulukutla V, Ibrahim A, Nagarajarao H. Advances in the management of atrial fibrillation with a special focus on non-pharmacological approaches to prevent thromboembolism: a review of current recommendations. J Investig Med 2020; 68:1317-1333. [PMID: 33203786 DOI: 10.1136/jim-2020-001500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2020] [Indexed: 11/04/2022]
Abstract
Atrial fibrillation (AFIB) is the most common heart rhythm abnormality and is associated with significant morbidity and mortality. While the treatment of AFIB involves strategies of rate with or without rhythm control, it is also essential to strategize appropriate therapies to prevent thromboembolic complications arising from AFIB. Previously, anticoagulation was the main treatment option which exposed patients to higher than usual risk of bleeding. However, with the advent of new technology, novel therapeutic options aimed at surgical or percutaneous exclusion or occlusion of the left atrial appendage in preventing thromboembolic complications from AFIB have evolved. This review evaluates recent advances and therapeutic options in treating AFIB with a special focus on both surgical and percutaneous interventions which can reduce and/or eliminate thromboembolic complications of AFIB.
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Affiliation(s)
- Malini Riddle
- Paul L Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, Texas, USA
| | - Richard McCallum
- Internal Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, Texas, USA
| | - Chandra Prakash Ojha
- Internal Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, Texas, USA
| | - Timir Kumar Paul
- Internal Medicine, East Tennessee State University James H Quillen College of Medicine, Johnson City, Tennessee, USA
| | - Vineet Gupta
- Department of Internal Medicine, University of California San Diego, La Jolla, California, USA
| | - David Alan Baran
- Cardiovascular Diseases, Sentara Healthcare Inc, Norfolk, Virginia, USA
| | - Bharat Ved Prakash
- Department of Medicine, Texas Tech University Health Sciences Center El Paso, Transmountain Campus, El Paso, Texas, USA
| | - Amogh Misra
- Department of Biochemistry, The University of Texas at Austin, Austin, Texas, USA
| | - Adriana Camila Mares
- Internal Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, Texas, USA
| | - Moeen Abedin
- Division of Cardiology, University Medical Center of El Paso, El Paso, Texas, USA
| | - Archana Kedar
- Internal Medicine, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | | | - Ahmed Ibrahim
- Internal Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, Texas, USA
| | - Harsha Nagarajarao
- Internal Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, Texas, USA
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6
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Roden DM. A current understanding of drug-induced QT prolongation and its implications for anticancer therapy. Cardiovasc Res 2020; 115:895-903. [PMID: 30689740 DOI: 10.1093/cvr/cvz013] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/18/2018] [Accepted: 01/16/2019] [Indexed: 01/08/2023] Open
Abstract
The QT interval, a global index of ventricular repolarization, varies among individuals and is influenced by diverse physiologic and pathophysiologic stimuli such as gender, age, heart rate, electrolyte concentrations, concomitant cardiac disease, and other diseases such as diabetes. Many drugs produce a small but reproducible effect on QT interval but in rare instances this is exaggerated and marked QT prolongation can provoke the polymorphic ventricular tachycardia 'torsades de pointes', which can cause syncope or sudden cardiac death. The generally accepted common mechanism whereby drugs prolong QT is block of a key repolarizing potassium current in heart, IKr, generated by expression of KCNH2, also known as HERG. Thus, evaluation of the potential that a new drug entity may cause torsades de pointes has relied on exposure of normal volunteers or patients to drug at usual and high concentrations, and on assessment of IKr block in vitro. More recent work, focusing on anticancer drugs with QT prolonging liability, is defining new pathways whereby drugs can prolong QT. Notably, the in vitro effects of some tyrosine kinase inhibitors to prolong cardiac action potentials (the cellular correlate of QT) can be rescued by intracellular phosphatidylinositol 3,4,5-trisphosphate, the downstream effector of phosphoinositide 3-kinase. This finding supports a role for inhibition of this enzyme, either directly or by inhibition of upstream kinases, to prolong QT through mechanisms that are being worked out, but include enhanced inward 'late' sodium current during the plateau of the action potential. The definition of non-IKr-dependent pathways to QT prolongation will be important for assessing risk, not only with anticancer therapies but also with other QT prolonging drugs and for generating a refined understanding how variable activity of intracellular signalling systems can modulate QT and associated arrhythmia risk.
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Affiliation(s)
- Dan M Roden
- Department of Medicine, Vanderbilt University Medical Center, 2215B Garland Avenue, Room 1285B, Nashville, TN, USA.,Department of Pharmacology, Vanderbilt University Medical Center, 2215B Garland Avenue, Room 1285B, Nashville, TN, USA.,Department of Biomedical Informatics, Vanderbilt University Medical Center, 2215B Garland Avenue, Room 1285B, Nashville, TN, USA
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Chagula DB, Rechciński T, Rudnicka K, Chmiela M. Ankyrins in human health and disease - an update of recent experimental findings. Arch Med Sci 2020; 16:715-726. [PMID: 32542072 PMCID: PMC7286341 DOI: 10.5114/aoms.2019.89836] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 02/25/2018] [Indexed: 12/17/2022] Open
Abstract
Ankyrins are adaptor molecules that in eukaryotic cells form complexes with ion channel proteins, cell adhesion and signalling molecules and components of the cytoskeleton. They play a pivotal role as scaffolding proteins, in the structural anchoring to the muscle membrane, in muscle development, neurogenesis and synapse formation. Dysfunction of ankyrins is implicated in numerous diseases such as hereditary spherocytosis, neurodegeneration of Purkinje cells, cardiac arrhythmia, Brugada syndrome, bipolar disorders and schizophrenia, congenital myopathies and congenital heart disease as well as cancers. Detecting either down- or over-expression of ankyrins and ergo their use as biomarkers can provide a new paradigm in the diagnosis of these diseases. This paper provides an outline of knowledge about the structure of ankyrins, and by making use of recent experimental research studies critically discusses their role in several health disorders. Moreover, therapeutic options utilizing engineered ankyrins, designed ankyrin repeat proteins (DARPins), are discussed.
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Affiliation(s)
- Damian B. Chagula
- Laboratory of Gastroimmunology, Department of Immunology and Infectious Biology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Tomasz Rechciński
- Department of Cardiology, Bieganski Regional Speciality Hospital, Medical University of Lodz, Lodz, Poland
| | - Karolina Rudnicka
- Laboratory of Gastroimmunology, Department of Immunology and Infectious Biology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Magdalena Chmiela
- Laboratory of Gastroimmunology, Department of Immunology and Infectious Biology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
- Corresponding author: Prof. Magdalena Chmiela Laboratory of Gastroimmunology, Department of Immmunology and Infectious Biology, Faculty of Biology and Environmental Protection, University of Lodz, 12/16 Banacha St, 90-237 Lodz, Poland, E-mail:
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Luceri RM, Kroll MW, Calkins H, Halperin H. Commentary on: Gibbons J, Mojica A, Peele M. Human electrical muscular incapacitation and effects on QTc interval. J Forensic Sci https://doi.org/10.1111/1556-4029.13490. Epub 2017 April 17. J Forensic Sci 2017; 62:1682-1683. [PMID: 29152803 DOI: 10.1111/1556-4029.13636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Richard M Luceri
- Cardiac Electrophysiology, Holy Cross Hospital, Ft. Lauderdale, FL
| | - Mark W Kroll
- University of Minnesota, Minneapolis, MN.,Cal Poly University, San Luis Obispo, CA
| | - Hugh Calkins
- Nicholas J. Fortuin M.D. Professor of Cardiology and Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.,Cardiac Arrhythmia Services, Baltimore, MD
| | - Henry Halperin
- Johns Hopkins University School of Medicine, Baltimore, MD.,Johns Hopkins Imaging Institute of Excellence, Baltimore, MD
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Riad FS, Razak E, Saba S, Shalaby A, Nemec J. Recent heart rate history affects QT interval duration in atrial fibrillation. PLoS One 2017; 12:e0172962. [PMID: 28273109 PMCID: PMC5342318 DOI: 10.1371/journal.pone.0172962] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 02/13/2017] [Indexed: 11/18/2022] Open
Abstract
QT interval prolongation is associated with a risk of polymorphic ventricular tachycardia. QT interval shortens with increasing heart rate and correction for this effect is necessary for meaningful QT interval assessment. We aim to improve current methods of correcting the QT interval during atrial fibrillation (AF). Digitized Holter recordings were analyzed from patients with AF. Models of QT interval dependence on RR intervals were tested by sorting the beats into 20 bins based on corrected RR interval and assessing ST-T variability within the bins. Signal-averaging within bins was performed to determine QT/RR dependence. Data from 30 patients (29 men, 69.3±7.3 years) were evaluated. QT behavior in AF is well described by a linear function (slope ~0.19) of steady-state corrected RR interval. Corrected RR is calculated as a combination of an exponential weight function with time-constant of 2 minutes and a smaller “immediate response” component (weight ~ 0.18). This model performs significantly (p<0.0001) better than models based on instantaneous RR interval only including Bazett and Fridericia. It also outperforms models based on shorter time-constants and other previously proposed models. This model may improve detection of repolarization delay in AF. QT response to heart rate changes in AF is similar to previously published QT dynamics during atrial pacing and in sinus rhythm.
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Affiliation(s)
- Fady S. Riad
- Department of Internal Medicine, The University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Eathar Razak
- Department of Cardiology, VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania, United States of America
| | - Samir Saba
- Heart and Vascular Institute, The University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Alaa Shalaby
- Department of Cardiology, VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania, United States of America
| | - Jan Nemec
- Heart and Vascular Institute, The University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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Jackobson G, Carmel NN, Lotan D, Kremer A, Justo D. Reckless administration of QT interval-prolonging agents in elderly patients with drug-induced torsade de pointes. Z Gerontol Geriatr 2016; 51:41-47. [DOI: 10.1007/s00391-016-1155-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 10/08/2016] [Accepted: 10/20/2016] [Indexed: 11/28/2022]
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Kirchhof P, Benussi S, Kotecha D, Ahlsson A, Atar D, Casadei B, Castella M, Diener HC, Heidbuchel H, Hendriks J, Hindricks G, Manolis AS, Oldgren J, Popescu BA, Schotten U, Van Putte B, Vardas P. 2016 ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS. Eur Heart J 2016; 37:2893-2962. [PMID: 27567408 DOI: 10.1093/eurheartj/ehw210] [Citation(s) in RCA: 4702] [Impact Index Per Article: 587.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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12
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Kirchhof P, Benussi S, Kotecha D, Ahlsson A, Atar D, Casadei B, Castella M, Diener HC, Heidbuchel H, Hendriks J, Hindricks G, Manolis AS, Oldgren J, Popescu BA, Schotten U, Van Putte B, Vardas P, Agewall S, Camm J, Baron Esquivias G, Budts W, Carerj S, Casselman F, Coca A, De Caterina R, Deftereos S, Dobrev D, Ferro JM, Filippatos G, Fitzsimons D, Gorenek B, Guenoun M, Hohnloser SH, Kolh P, Lip GYH, Manolis A, McMurray J, Ponikowski P, Rosenhek R, Ruschitzka F, Savelieva I, Sharma S, Suwalski P, Tamargo JL, Taylor CJ, Van Gelder IC, Voors AA, Windecker S, Zamorano JL, Zeppenfeld K. 2016 ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS. Eur J Cardiothorac Surg 2016; 50:e1-e88. [DOI: 10.1093/ejcts/ezw313] [Citation(s) in RCA: 602] [Impact Index Per Article: 75.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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Electrocardiographic Predictors of Torsadogenic Risk During Dofetilide or Sotalol Initiation: Utility of a Novel T Wave Analysis Program. Cardiovasc Drugs Ther 2016; 29:433-41. [PMID: 26411977 DOI: 10.1007/s10557-015-6619-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Initiation of class III anti-arrhythmic medications requires telemetric monitoring for ventricular arrhythmias and QT prolongation to reduce the risk of torsades de pointes (TdP). Heart rate-corrected QT interval (QTc) is an indicator of risk, however it is imperfect, and subtle abnormalities of repolarization have been linked with arrhythmogenesis. PURPOSE Identification of electrocardiographic predictors of torsadogenic risk through the application of a novel T wave analysis tool. METHODS Among all patients admitted to Mayo Clinic for initiation of dofetilide or sotalol, we identified 13 cases who developed drug-induced TdP and 26 age and sex matched controls that did not develop TdP. The immediate pre-TdP ECG of those with TdP was compared to the last ECG performed prior to hospital discharge in controls using a novel T wave program that quantified subtle changes in T wave morphology. RESULTS The QTc and 12 T wave parameters successfully distinguished TdP cases from controls. The top performing parameters were the QTc in lead V3 (mean case vs control 480 vs 420 msec, p < 0.001, r = 0.72) and T wave right slope in lead I (mean case vs control -840.29 vs -1668.71 mV/s, p = 0.002, r = 0.45). The addition of T wave right slope to QTc improved prediction accuracy from 79 to 88 %. CONCLUSION Our data demonstrate that, in addition to QTc, the T wave right slope is correlated strongly with TdP risk. This suggests that a computer-based repolarization measurement tool that integrates additional data beyond the QTc may identify patients with the greatest torsadogenic potential.
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Kirchhof P, Benussi S, Kotecha D, Ahlsson A, Atar D, Casadei B, Castella M, Diener HC, Heidbuchel H, Hendriks J, Hindricks G, Manolis AS, Oldgren J, Popescu BA, Schotten U, Van Putte B, Vardas P, Agewall S, Camm J, Baron Esquivias G, Budts W, Carerj S, Casselman F, Coca A, De Caterina R, Deftereos S, Dobrev D, Ferro JM, Filippatos G, Fitzsimons D, Gorenek B, Guenoun M, Hohnloser SH, Kolh P, Lip GYH, Manolis A, McMurray J, Ponikowski P, Rosenhek R, Ruschitzka F, Savelieva I, Sharma S, Suwalski P, Tamargo JL, Taylor CJ, Van Gelder IC, Voors AA, Windecker S, Zamorano JL, Zeppenfeld K. 2016 ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS. Europace 2016; 18:1609-1678. [PMID: 27567465 DOI: 10.1093/europace/euw295] [Citation(s) in RCA: 1305] [Impact Index Per Article: 163.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Stefan Agewall
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - John Camm
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Gonzalo Baron Esquivias
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Werner Budts
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Scipione Carerj
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Filip Casselman
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Antonio Coca
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Raffaele De Caterina
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Spiridon Deftereos
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Dobromir Dobrev
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - José M Ferro
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Gerasimos Filippatos
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Donna Fitzsimons
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Bulent Gorenek
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Maxine Guenoun
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Stefan H Hohnloser
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Philippe Kolh
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Gregory Y H Lip
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Athanasios Manolis
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - John McMurray
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Piotr Ponikowski
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Raphael Rosenhek
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Frank Ruschitzka
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Irina Savelieva
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Sanjay Sharma
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Piotr Suwalski
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Juan Luis Tamargo
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Clare J Taylor
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Isabelle C Van Gelder
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Adriaan A Voors
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Stephan Windecker
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Jose Luis Zamorano
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
| | - Katja Zeppenfeld
- The disclosure forms of all experts involved in the development of these guidelines are available on the ESC website http://www.escardio.org/guidelines
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McCauley M, Vallabhajosyula S, Darbar D. Proarrhythmic and Torsadogenic Effects of Potassium Channel Blockers in Patients. Card Electrophysiol Clin 2016; 8:481-93. [PMID: 27261836 DOI: 10.1016/j.ccep.2016.02.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The most common arrhythmia requiring drug treatment is atrial fibrillation (AF), which affects 2 to 5 million Americans and continues to be a major cause of morbidity and increased mortality. Despite recent advances in catheter-based and surgical therapies, antiarrhythmic drugs continue to be the mainstay of therapy for most patients with symptomatic AF. However, many antiarrhythmics block the rapid component of the cardiac delayed rectifier potassium current (IKr) as a major mechanism of action, and marked QT prolongation and pause-dependent polymorphic ventricular tachycardia (torsades de pointes) are major class toxicities.
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Affiliation(s)
- Mark McCauley
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago, 840 South Wood Street, Suite 920 (MC715), Chicago, IL 60612, USA
| | - Sharath Vallabhajosyula
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago, 840 South Wood Street, Suite 920 (MC715), Chicago, IL 60612, USA
| | - Dawood Darbar
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago, 840 South Wood Street, Suite 920 (MC715), Chicago, IL 60612, USA.
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16
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Lenhoff H, Darpö B, Ferber G, Rosenqvist M, Frick M. Reduction over time of QTc prolongation in patients with sotalol after cardioversion of atrial fibrillation. Heart Rhythm 2015; 13:661-8. [PMID: 26654918 DOI: 10.1016/j.hrthm.2015.11.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Indexed: 11/24/2022]
Abstract
BACKGROUND Sotalol is recommended to prevent relapse of atrial fibrillation after cardioversion (CV). Sotalol prolongs the action potential by blocking the rapid component of the delayed rectifier potassium current, which results in corrected QT (QTc) prolongation on the electrocardiogram. Pronounced QTc prolongation may lead to proarrhythmias and sudden death. OBJECTIVE We investigated the dynamics of the QTc interval during the week after CV in patients treated with sotalol compared with patients treated with a β-blocker. METHODS Patients who underwent elective CV for persistent atrial fibrillation and maintained sinus rhythm for 1 week were included prospectively. All patients were on the highest tolerable stable dose of metoprolol or sotalol. Twelve-lead electrocardiograms were recorded 1 hour and 1 week after CV. RESULTS A total of 104 patients on sotalol and 104 on metoprolol were included; clinical characteristics between groups were comparable. One hour after CV, the QTc interval was significantly longer in sotalol-treated patients than in metoprolol-treated patients (465 ± 25 ms vs 423 ± 30 ms; P ≤ .0001). After 1 week, the QTc interval was reduced by -20.3 ± 24 ms in sotalol-treated patients (P ≤ .001); no such effect was seen in metoprolol-treated patients (-2.5 ± 18 ms; P = 0.28). The heart rate was stable during the week in both groups. In multivariate analysis of sotalol-treated patients, factors contributing to pronounced reduction in the QTc interval were longer QTc interval after CV and renal function. CONCLUSION The QTc interval is significantly reduced during the week after CV to sinus rhythm in sotalol-treated patients. This provides insight into the increased risk of proarrhythmias in the immediate time period after CV.
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Affiliation(s)
- Hanna Lenhoff
- Department of Clinical Science and Education, Division of Cardiology, Karolinska Institute, South Hospital, Stockholm, Sweden.
| | - Börje Darpö
- Statistik Georg Ferber GmbH, Riehen, Switzerland
| | - Georg Ferber
- Statistik Georg Ferber GmbH, Riehen, Switzerland
| | - Mårten Rosenqvist
- Department of Clinical Sciences, Karolinska Institute, Danderyd Hospital, Stockholm, Sweden
| | - Mats Frick
- Department of Clinical Science and Education, Division of Cardiology, Karolinska Institute, South Hospital, Stockholm, Sweden
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17
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Yamaguchi Y, Mizumaki K, Nishida K, Sakamoto T, Kataoka N, Nakatani Y, Inoue H. Time-Dependent Changes in QT Dynamics after Initiation and Termination of Paroxysmal Atrial Fibrillation. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2015; 38:1418-24. [PMID: 26391623 DOI: 10.1111/pace.12746] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Revised: 08/18/2015] [Accepted: 08/18/2015] [Indexed: 11/27/2022]
Abstract
BACKGROUND Little is known about time-dependent changes in QT dynamics after initiation of atrial fibrillation (AF) and after restoration of sinus rhythm (SR) in patients with paroxysmal AF. METHODS Beat-to-beat QT and RR intervals in CM5 lead were measured automatically in 13 patients with both AF and SR on the single 24-hour Holter electrocardiology recording. QT-RR relation was analyzed at six periods of time: 1 hour before AF onset (Pre(0-1h)), 0-1 hour and 4-5 hours after AF onset (AF(0-1h) and AF(4-5h)), and 0-1 hour, 2-3 hours, and 4-5 hours after the restoration of SR (SR(0-1h), SR(2-3h), and SR(4-5h)). RESULTS QT-RR slope was gradually decreased after AF onset and gradually returned to the baseline level after restoration of SR. The slope became greater at SR(4-5h) than at AF(4-5h) and AF(0-1h). In patients receiving antiarrhythmic drugs (AADs; n = 5), QT-RR slope was greater at SR(4-5h) than in those not receiving AADs (n = 8). CONCLUSION In patients with paroxysmal AF, bradycardia-dependent QT prolongation was attenuated during AF, and was corrected and gradually augmented along with continuation of SR, especially in patients receiving AADs. This could increase the risk of developing torsade de pointes.
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Affiliation(s)
- Yoshiaki Yamaguchi
- Second Department of Internal Medicine, Graduate School of Medicine, University of Toyama, Toyama, Japan
| | - Koichi Mizumaki
- Clinical Research and Ethics Center, University of Toyama, Toyama, Japan
| | - Kunihiro Nishida
- Second Department of Internal Medicine, Graduate School of Medicine, University of Toyama, Toyama, Japan
| | - Tamotsu Sakamoto
- Second Department of Internal Medicine, Graduate School of Medicine, University of Toyama, Toyama, Japan
| | - Naoya Kataoka
- Second Department of Internal Medicine, Graduate School of Medicine, University of Toyama, Toyama, Japan
| | - Yosuke Nakatani
- Second Department of Internal Medicine, Graduate School of Medicine, University of Toyama, Toyama, Japan
| | - Hiroshi Inoue
- Second Department of Internal Medicine, Graduate School of Medicine, University of Toyama, Toyama, Japan
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18
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Cheng R, Chan AP, Ehdaie A, Bersohn MM. Heeding the sign: macroscopic T-wave alternans. Am J Med 2015; 128:480-3. [PMID: 25637757 DOI: 10.1016/j.amjmed.2015.01.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 01/13/2015] [Accepted: 01/14/2015] [Indexed: 11/18/2022]
Affiliation(s)
| | - Amy P Chan
- Cedars-Sinai Heart Institute, Los Angeles, Calif; Division of Cardiology, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles
| | - Ashkan Ehdaie
- Cedars-Sinai Heart Institute, Los Angeles, Calif; Division of Cardiology, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles
| | - Malcolm M Bersohn
- Division of Cardiology, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles; David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles.
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19
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Nachimuthu S, Assar MD, Schussler JM. Drug-induced QT interval prolongation: mechanisms and clinical management. Ther Adv Drug Saf 2014; 3:241-53. [PMID: 25083239 DOI: 10.1177/2042098612454283] [Citation(s) in RCA: 188] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The prolonged QT interval is both widely seen and associated with the potentially deadly rhythm, Torsades de Pointes (TdP). While it can occur spontaneously in the congenital form, there is a wide array of drugs that have been implicated in the prolongation of the QT interval. Some of these drugs have either been restricted or withdrawn from the market due to the increased incidence of fatal polymorphic ventricular tachycardia. The list of drugs that cause QT prolongation continues to grow, and an updated list of specific drugs that prolong the QT interval can be found at www.qtdrugs.org. This review focuses on the mechanism of drug-induced QT prolongation, risk factors for TdP, culprit drugs, prevention and monitoring of prolonged drug-induced QT prolongation and treatment strategies.
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Affiliation(s)
- Senthil Nachimuthu
- Baylor University Medical Center, Jack and Jane Hamilton, Heart and Vascular Hospital Dallas, TX, USA
| | - Manish D Assar
- Baylor University Medical Center, Jack and Jane Hamilton, Heart and Vascular Hospital Dallas, TX, USA
| | - Jeffrey M Schussler
- Baylor University Medical Center, Jack and Jane Hamilton, Heart and Vascular Hospital, 621 North Hall Street, Suite 500, Dallas, TX 75226, USA
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20
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Chain ASY, Dieleman JP, van Noord C, Hofman A, Stricker BHC, Danhof M, Sturkenboom MCJM, Della Pasqua O. Not-in-trial simulation I: Bridging cardiovascular risk from clinical trials to real-life conditions. Br J Clin Pharmacol 2014; 76:964-72. [PMID: 23617533 DOI: 10.1111/bcp.12151] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Accepted: 04/04/2013] [Indexed: 01/08/2023] Open
Abstract
AIMS The assessment of heart rate-corrected QT (QTc) interval prolongation relies on the evidence of drug effects in healthy subjects. This study demonstrates the relevance of pharmacokinetic-pharmacodynamic (PKPD) relationships to characterize drug-induced QTc interval prolongation and explore the discrepancies between clinical trials and real-life conditions. METHODS d,l-Sotalol data from healthy subjects and from the Rotterdam Study cohort were used to assess treatment response in a phase I setting and in a real-life conditions, respectively. Using modelling and simulation, drug effects at therapeutic doses were predicted in both populations. RESULTS Inclusion criteria were shown to restrict the representativeness of the trial population in comparison to real-life conditions. A significant part of the typical patient population was excluded from trials due to weight and baseline QTc interval criteria. Relative risk was significantly different between sotalol users with and without heart failure, hypertension, diabetes and myocardial infarction (P < 0.01). Although drug effects do cause an increase in the relative risk of QTc interval prolongation, the presence of diabetes represented an increase from 4.0 [95% confidence interval (CI) 2.7-5.8] to 6.5 (95% CI 1.6-27.1), whilst for myocardial infarction it increased from 3.4 (95% CI 2.3-5.13) to 15.5 (95% CI 4.9-49.3). CONCLUSIONS Our findings show that drug effects on QTc interval do not explain the observed QTc values in the population. The prevalence of high QTc values in the real-life population can be assigned to co-morbidities and concomitant medications. These findings substantiate the need to account for these factors when evaluating the cardiovascular risk of medicinal products.
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Affiliation(s)
- Anne S Y Chain
- Leiden/Amsterdam Center for Drug Research, Division of Pharmacology, Leiden University, 2300 RA, Leiden, The Netherlands; Department of Medical Informatics, Erasmus Medical Centre, 3015 GE, Rotterdam, The Netherlands
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21
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Yang T, Chun YW, Stroud DM, Mosley JD, Knollmann BC, Hong C, Roden DM. Screening for acute IKr block is insufficient to detect torsades de pointes liability: role of late sodium current. Circulation 2014; 130:224-34. [PMID: 24895457 DOI: 10.1161/circulationaha.113.007765] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND New drugs are routinely screened for IKr blocking properties thought to predict QT prolonging and arrhythmogenic liability. However, recent data suggest that chronic (hours) drug exposure to phosphoinositide 3-kinase inhibitors used in cancer can prolong QT by inhibiting potassium currents and increasing late sodium current (INa-L) in cardiomyocytes. We tested the extent to which IKr blockers with known QT liability generate arrhythmias through this pathway. METHODS AND RESULTS Acute exposure to dofetilide, an IKr blocker without other recognized electropharmacologic actions, produced no change in ion currents or action potentials in adult mouse cardiomyocytes, which lack IKr. By contrast, 2 to 48 hours of exposure to the drug generated arrhythmogenic afterdepolarizations and ≥15-fold increases in INa-L. Including phosphatidylinositol 3,4,5-trisphosphate, a downstream effector for the phosphoinositide 3-kinase pathway, in the pipette inhibited these effects. INa-L was also increased, and inhibitable by phosphatidylinositol 3,4,5-trisphosphate, with hours of dofetilide exposure in human-induced pluripotent stem cell-derived cardiomyocytes and in Chinese hamster ovary cells transfected with SCN5A, encoding sodium current. Cardiomyocytes from dofetilide-treated mice similarly demonstrated increased INa-L and afterdepolarizations. Other agents with variable IKr-blocking potencies and arrhythmia liability produced a range of effects on INa-L, from marked increases (E-4031, d-sotalol, thioridazine, and erythromycin) to little or no effect (haloperidol, moxifloxacin, and verapamil). CONCLUSIONS Some but not all drugs designated as arrhythmogenic IKr blockers can generate arrhythmias by augmenting INa-L through the phosphoinositide 3-kinase pathway. These data identify a potential mechanism for individual susceptibility to proarrhythmia and highlight the need for a new paradigm to screen drugs for QT prolonging and arrhythmogenic liability.
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Affiliation(s)
- Tao Yang
- From the Vanderbilt University School of Medicine, Nashville, TN
| | - Young Wook Chun
- From the Vanderbilt University School of Medicine, Nashville, TN
| | - Dina M Stroud
- From the Vanderbilt University School of Medicine, Nashville, TN
| | | | | | - Charles Hong
- From the Vanderbilt University School of Medicine, Nashville, TN
| | - Dan M Roden
- From the Vanderbilt University School of Medicine, Nashville, TN.
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22
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Osadchii OE. Impaired epicardial activation-repolarization coupling contributes to the proarrhythmic effects of hypokalaemia and dofetilide in guinea pig ventricles. Acta Physiol (Oxf) 2014; 211:48-60. [PMID: 24533513 DOI: 10.1111/apha.12259] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 01/09/2014] [Accepted: 02/10/2014] [Indexed: 11/30/2022]
Abstract
AIM Activation-repolarization coupling refers to the inverse relationship between action potential duration and activation time in myocardial regions along the path of ventricular excitation. This study examined whether the activation-repolarization coupling plays a role in coordinating repolarization times between the right ventricular (RV) and left ventricular (LV) chambers, and if impaired coordination contributes to electrical instability produced by hypokalaemia or dofetilide, a blocker of the delayed rectifier K(+) current. METHODS In Langendorff-perfused, isolated guinea pig hearts, six monophasic action potential recording electrodes were attached to RV and LV epicardium. Local activation time and action potential duration (APD90 ) were determined during spontaneous beating, regular pacing and extrasystolic excitation. RESULTS In regularly beating hearts, the RV epicardial sites had longer APD90 , but exhibited earlier activation times, as compared to LV sites, which minimized the interventricular difference in repolarization time. Upon extrasystolic stimulation, the APD90 was reduced to a greater extent in RV compared with LV, which translated to a reversed slope of APD90 -to-activation time relationship, and increased spatial repolarization gradients. Hypokalaemia and dofetilide prolonged APD90 , with the effect being greater in LV compared with RV. In hypokalaemic hearts, LV activation was delayed. These changes contributed to increased asynchrony in repolarization times in the LV and RV in both regular and extrasystolic beats, and enhanced susceptibility to tachyarrhythmia. CONCLUSION Impaired RV-to-LV activation-repolarization coupling is an important determinant of electrical instability in the setting of non-uniformly prolonged epicardial APD90 or slowed interventricular conduction.
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Affiliation(s)
- O. E. Osadchii
- Department of Biomedical Sciences; University of Copenhagen; Copenhagen N Denmark
- Department of Health Science and Technology; University of Aalborg; Aalborg Denmark
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23
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Weeke P, Delaney J, Mosley JD, Wells Q, Van Driest S, Norris K, Kucera G, Stubblefield T, Roden DM. QT variability during initial exposure to sotalol: experience based on a large electronic medical record. Europace 2013; 15:1791-7. [PMID: 23787903 DOI: 10.1093/europace/eut153] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
AIMS A prolonged QT interval is associated with increased risk of Torsades de pointes (TdP) and may be fatal. We sought to investigate the extent to which clinical covariates affect the change in QT interval among 'real-world' patients treated with sotalol and followed in an electronic medical record (EMR) system. METHODS AND RESULTS We used clinical alerts in our EMR system to identify all patients in whom a new prescription for sotalol was written (2001-11). Rate-corrected QT (QTc) was calculated by Bazett's formula. Correlates of sotalol-induced change in the QTc interval and sotalol discontinuation were examined using linear and logistic regression, respectively. Overall, 541 sotalol-exposed patients were identified (n = 200 women, 37%). The mean first sotalol dose was 86 ± 39 mg, age 64 ± 13 years, and BMI 30 ± 7 kg/m(2). Atrial fibrillation/flutter was the predominant indication (92.2%). After initial exposure, the change in the QTc interval from baseline was highly variable: ΔQTc after 2 h = 3 ± 42 ms (P = 0.17) and 11 ± 37 ms after ≥48 h (P < 0.001). Multivariable linear regression analysis identified female gender and age, reduced left ventricular ejection fraction, high sotalol dose, hypertrophic cardiomyopathy, and loop diuretic co-administration as correlates of increased ΔQTc at ≥48 h (P < 0.05 for all). Within 3 days of initiation, 12% discontinued sotalol of which 31% were because of exaggerated QTc prolongation. One percent developed TdP. CONCLUSION In this EMR-based cohort, the increase in QTc with sotalol initiation was highly variable, and multiple clinical factors contributed. These data represent an important step in ongoing work to identify real-world patients likely to tolerate long-term therapy and reinforces the utility of EMR-based cohorts as research tools.
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Affiliation(s)
- Peter Weeke
- Department of Medicine and Clinical Pharmacology, Vanderbilt University, 1285 Medical Research Building IV, Nashville, TN 37232, USA
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24
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Abstract
PURPOSE Dofetilide is class III antiarrhythmic agent which prolongs cardiac action potential duration because of selective inhibition of I (Kr), the rapid component of the delayed rectifier K(+) current. Although clinical studies reported on proarrhythmic risk associated with dofetilide treatment, the contributing electrophysiological mechanisms remain poorly understood. This study was designed to determine if dofetilide-induced proarrhythmia may be attributed to abnormalities in ventricular repolarization and refractoriness. METHODS The monophasic action potential duration and effective refractory periods (ERP) were assessed at distinct epicardial and endocardial sites along with volume-conducted ECG recordings in isolated, perfused guinea-pig heart preparations. RESULTS Dofetilide was found to produce the reverse rate-dependent prolongation of ventricular repolarization, increased the steepness of action potential duration rate adaptation, and amplified transepicardial variability in electrical restitution kinetics. Dofetilide also prolonged the T peak-to-end interval on ECG, and elicited a greater prolongation of endocardial than epicardial ERP, thereby increasing transmural dispersion of refractoriness. At epicardium, dofetilide prolonged action potential duration to a greater extent than ERP, thus extending the critical interval for ventricular re-excitation. This change was associated with triangulation of epicardial action potential because of greater dofetilide-induced prolonging effect at 90 % than 30 % repolarization. Premature ectopic beats and spontaneous short-lasting episodes of monomorphic ventricular tachycardia were observed in 44 % of dofetilide-treated heart preparations. CONCLUSIONS Proarrhythmic potential of dofetilide in guinea-pig heart is attributed to steepened electrical restitution, increased transepicardial variability in electrical restitution kinetics, amplified transmural dispersion of refractoriness, increased critical interval for ventricular re-excitation, and triangulation of epicardial action potential.
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Affiliation(s)
- Oleg E Osadchii
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark.
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25
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Morley SR. Drug-Induced Long QT Syndrome - Clinical and Analytical Aspects for Medical Examiners. Acad Forensic Pathol 2012. [DOI: 10.23907/2012.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The long QT syndrome may occur due to genetic aberrations of cardiac transcellular ionic transporters, but also occurs secondary to a wide range of therapeutic and illicit drugs. This review will outline how the interaction of the blockade of the cardiac ion channels with drugs may lead to death from the long QT syndrome. Toxicology laboratories have a role, although somewhat limited, in supporting the investigation of sudden adult death and the contribution to the etiology of the long QT syndrome.
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Affiliation(s)
- Stephen R. Morley
- Sheffield Teaching Hospitals and an honorary senior lecturer at Sheffield University and Kings College London, all in the United Kingdom
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Affiliation(s)
- Andrew J Sauer
- Center for Human Genetic Research, Cardiovascular Research Center, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA
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Kallergis EM, Goudis CA, Simantirakis EN, Kochiadakis GE, Vardas PE. Mechanisms, risk factors, and management of acquired long QT syndrome: a comprehensive review. ScientificWorldJournal 2012; 2012:212178. [PMID: 22593664 PMCID: PMC3347892 DOI: 10.1100/2012/212178] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 12/22/2011] [Indexed: 12/19/2022] Open
Abstract
Long QT syndrome is characterized by prolongation of the corrected QT (QTc) interval on the surface electrocardiogram and is associated with precipitation of torsade de pointes (TdP), a polymorphic ventricular tachycardia that may cause sudden death. Acquired long QT syndrome describes pathologic excessive prolongation of the QT interval, upon exposure to an environmental stressor, with reversion back to normal following removal of the stressor. The most common environmental stressor in acquired long QT syndrome is drug therapy. Acquired long QT syndrome is an important issue for clinicians and a significant public health problem concerning the large number of drugs with this adverse effect with a potentially fatal outcome, the large number of patients exposed to these drugs, and our inability to predict the risk for a given individual. In this paper, we focus on mechanisms underlying QT prolongation, risk factors for torsades de pointes and describe the short- and long-term treatment of acquired long QT syndrome.
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Affiliation(s)
- Eleftherios M Kallergis
- Department of Cardiology, University Hospital of Heraklion, 711 10 Heraklion, Crete, Greece.
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Dunnink A, van Opstal JM, Oosterhoff P, Winckels SKG, Beekman JDM, van der Nagel R, Cora Verduyn S, Vos MA. Ventricular remodelling is a prerequisite for the induction of dofetilide-induced torsade de pointes arrhythmias in the anaesthetized, complete atrio-ventricular-block dog. Europace 2011; 14:431-6. [DOI: 10.1093/europace/eur311] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Abstract
The drug-induced long QT syndrome is a distinct clinical entity that has evolved from an electrophysiologic curiosity to a centerpiece in drug regulation and development. This evolution reflects an increasing recognition that a rare adverse drug effect can profoundly upset the balance between benefit and risk that goes into the prescription of a drug by an individual practitioner as well as the approval of a new drug entity by a regulatory agency. This review will outline how defining the central mechanism, block of the cardiac delayed-rectifier potassium current I(Kr), has contributed to defining risk in patients and in populations. Models for studying risk, and understanding the way in which clinical risk factors modulate cardiac repolarization at the molecular level are discussed. Finally, the role of genetic variants in modulating risk is described.
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Affiliation(s)
- Prince Kannankeril
- Oates Institute for Experimental Therapeutics, Vanderbilt University School of Medicine, Nashville, TN 37232-0575, USA
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Fujiki A, Yoshioka R, Sakabe M, Kusuzaki S. QT/RR relation during atrial fibrillation based on a single beat analysis in 24-h Holter ECG: the role of the second and further preceding RR intervals in QT modification. J Cardiol 2011; 57:269-74. [PMID: 21382691 DOI: 10.1016/j.jjcc.2011.01.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Revised: 01/08/2011] [Accepted: 01/24/2011] [Indexed: 11/29/2022]
Abstract
BACKGROUND During atrial fibrillation (AF) irregularity of RR intervals may modify QT/RR relation differently from sinus rhythm. The purpose of this study was to compare QT/RR relation based on a single-beat analysis using the first preceding RR interval with the modified RR interval reflecting not only the first preceding but also the second and further preceding RR intervals during AF. METHODS QT and RR intervals were measured using an automatic QT analyzing system in 32 patients who had both AF and sinus rhythm on the same 24-h Holter ECG recording. In 12 patients antiarrhythmic drugs (AADs) were administered. To reflect irregularity of the preceding RR intervals during AF, a modified RR (mRR) using a weighted average of five successive RR intervals: (5RR(1)+2RR(2)+RR(3)+RR(4)+RR(5))/10 was adopted. Linear regression analyses between QT and RR intervals were performed using the preceding RR(1) (QT/RR) and the modified RR (QT/mRR) during AF. RESULTS During AF the slope of QT/RR was lower than that of QT/mRR and was also lower than that of QT/RR during sinus rhythm in patients with and without AAD. Slopes of regression line in QT/RR during sinus rhythm, QT/RR and QT/mRR during AF were steeper in patients with AAD than those in patients without. Slopes of QT/RR during sinus rhythm correlated with those of QT/mRR (r=0.79, p<0.01) better than those of QT/RR (r=0.64, p<0.05) during AF. QT interval at an RR interval of 1.20s or 1.00 s obtained from QT/RR during AF was significantly smaller than that during sinus rhythm in patients with and without AAD. CONCLUSIONS The slope of QT/mRR during AF became closer to that of QT/RR during sinus rhythm compared with that of QT/RR during AF. QT interval during sinus rhythm could be estimated better using QT/mRR than using QT/RR during AF.
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Affiliation(s)
- Akira Fujiki
- Division of Cardiology, Shizuoka Red Cross Hospital, 8-2 Otemachi Aoiku, Shizuoka 420-0853, Japan.
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Gottfridsson C, Karlsson T, Edvardsson N. The signal-averaged electrocardiogram before and after electrical cardioversion of persistent atrial fibrillation—implications of the sudden change in rhythm. J Electrocardiol 2011; 44:242-50. [DOI: 10.1016/j.jelectrocard.2010.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Indexed: 11/16/2022]
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Fujiki A, Sakabe M. Comparison of QT/RR relation based on a 15-s averaged ECG and a single beat ECG during atrial fibrillation. Circ J 2010; 75:274-9. [PMID: 21178289 DOI: 10.1253/circj.cj-10-0654] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND The aim of this study was to compare QT/RR relation based on a 15-s averaged beat ECG with a single beat ECG during atrial fibrillation (AF) and to determine which was better to estimate the QT interval after sinus restoration. METHODS AND RESULTS QT and RR intervals were measured using an automatic QT analyzing system in 33 patients who had both AF and sinus rhythm on the same 24-h Holter ECG recording. In 14 patients, antiarrhythmic drugs (AAD) were administered. QT/RR relations were analyzed from ECG waves obtained by the summation of consecutive QRS-T complexes during each 15-s period (QT/RR-average) and a single beat QRS-T (QT/RR-single). During sinus rhythm, the slope of QT/RR-average did not differ from that of QT/RR-single in patients with and without AAD. On the other hand, during AF, the slope of QT/RR-average was significantly greater than that of QT/RR-single (without AAD: 0.12±0.06 vs. 0.06±0.03, P<0.001; with AAD: 0.15±0.05 vs. 0.08±0.04, P<0.001). During AF, the QT interval at an RR interval of 1.2-s (QT-1.2) determined from QT/RR-average was significantly greater than QT-1.2 from QT/RR-single in patients with and without AAD. QT-1.2 in QT/RR-single during AF was significantly smaller than that during sinus rhythm but QT-1.2 in QT/RR-average during AF was not. CONCLUSIONS The QT interval after sinus restoration could be estimated better using QT/RR-average than using QT/RR-single during AF.
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Affiliation(s)
- Akira Fujiki
- Division of Cardiology, Shizuoka Red Cross Hospital, Shizuoka, Japan.
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Haraoka K, Morita H, Saito Y, Toh N, Miyoshi T, Nishii N, Nagase S, Nakamura K, Kohno K, Kusano KF, Kawaguchi K, Ohe T, Ito H. Fragmented QRS is associated with torsades de pointes in patients with acquired long QT syndrome. Heart Rhythm 2010; 7:1808-14. [DOI: 10.1016/j.hrthm.2010.09.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Accepted: 09/07/2010] [Indexed: 10/19/2022]
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Farkas AS, Nattel S. Minimizing Repolarization-Related Proarrhythmic Risk in Drug Development and Clinical Practice. Drugs 2010; 70:573-603. [DOI: 10.2165/11535230-000000000-00000] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Mitamura H. Prevention of Torsade de Pointes during the Pharmacologic Treatment of Atrial Fibrillation. J Arrhythm 2010. [DOI: 10.1016/s1880-4276(10)80030-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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DAY GEOFFREYA, PADANILAM BENZYJ, FOGEL RICHARDI, PRYSTOWSKY ERICN. Pacing Threshold Testing Induced Ventricular Fibrillation Following Acute Rate Control of Atrial Fibrillation. J Cardiovasc Electrophysiol 2009; 20:1405-7. [DOI: 10.1111/j.1540-8167.2009.01505.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Drolet B, Simard C, Gailis L, Daleau P. Ischemic, genetic and pharmacological origins of cardiac arrhythmias: the contribution of the Quebec Heart Institute. Can J Cardiol 2009; 23 Suppl B:15B-22B. [PMID: 17932583 DOI: 10.1016/s0828-282x(07)71006-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Research in the field of basic electrophysiology at the Quebec Heart Institute (Laval Hospital, Quebec City, Quebec) has evolved since its beginning in the 1990s. Interests were focused on cardiac arrhythmias induced by drugs, allelic variants and metabolic factors produced during ischemia. The results have contributed to the creation of new standards in drug development, more specifically, testing all new drugs for their potential effects on cardiac potassium currents, which could produce life-threatening proarrhythmic effects. In a French-Canadian population, three heterozygous single nucleotide polymorphisms in hK(v)1.5, a gene encoding for a major atrial repolarizing current, were found. These variants affect the expression level of the hK(v)1.5 channel and change the inactivation process in the presence of its accessory beta subunit. Because these effects could shorten atrial action potential, their presence was tested in postcoronary bypass patients and a higher prevalence was found in patients with postoperative atrial fibrillation. Finally, three potentially proarrhythmic factors characteristic of ischemia were identified: pH decrease; oxygen free radicals, which both increase the flow of K(+) ions through human ether-a-go-go-related gene and hK(v)1.5, producing a reduction in action potential duration, frequently leading to cardiac arrhythmias; and lysophosphatidylcholine, a metabolite involved in the production of cardiac arrhythmias early during ischemia that was shown to be a major cause of electrical uncoupling. Over the past decade, the Quebec Heart Institute has provided a significant amount of original data in the field of basic cardiac electrophysiology, specifically concerning arrhythmias originating from pharmacological agents, genetic background and cardiac ischemia.
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Watanabe H, Kaiser DW, Makino S, MacRae CA, Ellinor PT, Wasserman BS, Kannankeril PJ, Donahue BS, Roden DM, Darbar D. ACE I/D polymorphism associated with abnormal atrial and atrioventricular conduction in lone atrial fibrillation and structural heart disease: implications for electrical remodeling. Heart Rhythm 2009; 6:1327-32. [PMID: 19648063 DOI: 10.1016/j.hrthm.2009.05.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2008] [Accepted: 05/11/2009] [Indexed: 12/19/2022]
Abstract
BACKGROUND The angiotensin-converting enzyme (ACE) gene contains a common polymorphism based on the insertion (I) or deletion (D) of a 287-bp intronic DNA fragment. The D allele is associated with higher ACE activity and thus higher angiotensin II levels. Angiotensin II stimulates cardiac fibrosis and conduction heterogeneity. OBJECTIVE The purpose of this study was to determine whether the ACE I/D polymorphism modulates cardiac electrophysiology. METHODS Three different cohorts of patients were studied: 69 patients with paroxysmal lone atrial fibrillation (AF), 151 patients with structural heart disease and no history of AF, and 161 healthy subjects without cardiovascular disease or AF. Patients taking drugs that affect cardiac conduction were excluded from the study. ECG parameters during sinus rhythm were compared among the ACE I/D genotypes. RESULTS The ACE I/D polymorphism was associated with the PR interval and heart block in the lone AF cohort. In multivariable linear regression models, the D allele was associated with longer PR interval in the lone AF and heart disease cohorts (12.0-ms and 7.1-ms increase per D allele, respectively). P-wave duration showed a similar trend, with increase in PR interval across ACE I/D genotypes in the lone AF and heart disease cohorts. CONCLUSION The ACE D allele is associated with electrical remodeling in patients with lone AF and in those with heart disease, but not in control subjects. ACE activity may play a role in cardiac remodeling after the development of AF and heart disease.
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Affiliation(s)
- Hiroshi Watanabe
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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Abstract
Striking QT prolongation and the morphologically distinctive ventricular tachycardia torsades de pointes can occur in up to 5% of patients treated with certain antiarrhythmic drugs. This adverse drug reaction also occurs, albeit far less frequently, during therapy with a range of drugs not used for cardiovascular indications; examples include certain antibiotics, antipsychotics and antihistamines. The common mechanism for drug-induced torsades de pointes is inhibition of a specific repolarizing potassium current, I(Kr). The key question facing clinicians, regulators and those who develop drugs is why torsades de pointes only occurs in some patients exposed to I(Kr) block. This paper reviews the clinical, cellular, molecular and genetic features of the arrhythmia that may provide an answer to this question and proposes future studies in this area.
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Kannankeril PJ. Understanding drug-induced torsades de pointes: a genetic stance. Expert Opin Drug Saf 2008; 7:231-9. [PMID: 18462182 DOI: 10.1517/14740338.7.3.231] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Drugs may produce a variety of arrhythmias, but drug-induced QT prolongation and the risk of the polymorphic ventricular tachycardia torsades de pointes (drug-induced long QT syndrome) has garnered the most attention. The wide array of drugs with potential for QT prolongation, the correspondingly large number of patients exposed to such drugs, the difficulty in predicting an individual's risk, and the potentially fatal outcome, make drug-induced long QT syndrome an important public health problem for clinicians, researchers, drug development programs, and regulatory agencies. This review focuses on the genetic risk factors and mechanisms underlying QT prolongation and proarrhythmia. The post-genomic era hints at an improved understanding (and prediction) of how the gene-environment interaction produces this particular adverse drug response.
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Affiliation(s)
- Prince J Kannankeril
- Vanderbilt Children's Hospital, Division of Cardiology, 2200 Children's Way, Suite 5230, Nashville, TN 37232-9119, USA.
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Saluja D, Guyotte JA, Reiffel JA. An Improved QT Correction Method for use in Atrial Fibrillation and a Comparison with the Assessment of QT in Sinus Rhythm. J Atr Fibrillation 2008; 1:9. [PMID: 28496565 DOI: 10.4022/jafib.9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 02/28/2008] [Accepted: 04/07/2008] [Indexed: 01/18/2023]
Abstract
BACKGROUND Conventional QT corrections may be inappropriate inatrial fibrillation (AF) due to RR variability and QT lag. Existing formulashave been modified by the formula RRmod to account for this lag. Wedeveloped a novel correction formula for use in AF (QTAF) based onthe slope ∆QT/∆RRmod and report its performance in AF.We also compare QTAF obtained in AF with rate-independentcorrections in NSR. MATERIALS AND METHODS A total of 3063 RR/QT pairs from 28 patients with AFwere measured, 22 of whom also had measurements during sinus rhythm. QTc (theBazett equation), QTLC (the Framingham linear correction), and QTAFwere calculated utilizing RRmod, and the rate-independence of eachformula in AF tested. Mean QTAF values in AF were compared to QTintervals corrected with QTLC in normal sinus rhythm. RESULTS ∆QTc/∆RRmod and∆QTLC/∆RRmod slopes were significantlynon-zero whereas ∆QTAF/∆RRmod was not. QTLCand QTc corrections were imperfect at extremes of RRmod whileQTAF was constant. QTAF corrections in AF were shorterthan QTc or QTLC corrections in NSR. CONCLUSIONS QTAF is a novel QT correction with adefined relationship to correction in NSR that performs better than existingstrategies.
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Affiliation(s)
- Deepak Saluja
- Columbia University, College of Physicians and Surgeons, New York, NY
| | | | - James A Reiffel
- Columbia University, College of Physicians and Surgeons, New York, NY
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Darbar D, Kimbrough J, Jawaid A, McCray R, Ritchie MD, Roden DM. Persistent atrial fibrillation is associated with reduced risk of torsades de pointes in patients with drug-induced long QT syndrome. J Am Coll Cardiol 2008; 51:836-42. [PMID: 18294569 DOI: 10.1016/j.jacc.2007.09.066] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Revised: 09/14/2007] [Accepted: 09/19/2007] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The goal of this study was to identify markers of torsades de pointes (TdP) in patients with drug-associated long QT syndrome (LQTS). BACKGROUND Drug-induced LQTS includes individuals developing marked prolongation of ventricular repolarization on exposure to an offending drug. Under these conditions, TdP develops in some but not all patients. METHODS This was a case-control study of 123 adults with drug-associated LQTS. Patients were divided into LQTS only (LQTS; n = 40, QT >500 ms on drug) and LQTS + TdP (TdP; n = 83). RESULTS Baseline QT intervals were similar in the 2 groups (381 +/- 38 ms [LQTS] vs. 388 +/- 43 ms [TdP]). Clinical variables associated with risk of TdP included hypokalemia and female gender; by contrast, persistent atrial fibrillation (AF) at the time of drug discontinuation for QT prolongation was protective despite similar heart rates in AF and sinus rhythm (n = 20, 71 +/- 13 beats/min vs. 69 +/- 13 beats/min). Electrocardiographic variables that significantly increased the risk for TdP included absolute and rate-corrected QT intervals (QTc) on drug therapy, the magnitude of QT and QTc interval prolongation, and the change in T(peak) to T(end) (DeltaT(p)-T(e)), a relatively new index of transmural dispersion of repolarization and potential arrhythmogenicity. Multivariable logistic regression analysis revealed that only gender was predictive for TdP, whereas persistent AF at the time of drug discontinuation for QT prolongation (odds ratio 0.14, 95% confidence interval 0.03 to 0.63, p = 0.01) was negatively associated with the arrhythmia. CONCLUSIONS This study strongly suggests that despite ongoing rate irregularity, AF reduces the likelihood of developing TdP after the administration of drugs that prolong cardiac repolarization.
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Affiliation(s)
- Dawood Darbar
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37323-6602, USA.
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Roden DM, Kannankeril P, Darbar D. On the relationship among QT interval, atrial fibrillation, and torsade de pointes. Europace 2008; 9 Suppl 4:iv1-3. [PMID: 17766319 PMCID: PMC2599908 DOI: 10.1093/europace/eum165] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Dan M Roden
- Department of Medicine, Pediatrics, and Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Identifying genetic risk factors for serious adverse drug reactions: current progress and challenges. Nat Rev Drug Discov 2007; 6:904-16. [PMID: 17971785 DOI: 10.1038/nrd2423] [Citation(s) in RCA: 251] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Serious adverse drug reactions (SADRs) are a major cause of morbidity and mortality worldwide. Some SADRs may be predictable, based upon a drug's pharmacodynamic and pharmacokinetic properties. Many, however, appear to be idiosyncratic. Genetic factors may underlie susceptibility to SADRs and the identification of predisposing genotypes may improve patient management through the prospective selection of appropriate candidates. Here we discuss three specific SADRs with an emphasis on genetic risk factors. These SADRs, selected based on wide-sweeping clinical interest, are drug-induced liver injury, statin-induced myotoxicity and drug-induced long QT and torsades de pointes. Key challenges for the discovery of predictive risk alleles for these SADRs are also considered.
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Darbar D, Hardin B, Harris P, Roden DM. A rate-independent method of assessing QT-RR slope following conversion of atrial fibrillation. J Cardiovasc Electrophysiol 2007; 18:636-41. [PMID: 17488270 DOI: 10.1111/j.1540-8167.2007.00817.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Following conversion of atrial fibrillation (AF), QT interval transiently and variably prolongs and can trigger torsades de pointes (TdP). However, quantitative analysis of risk in this setting is difficult because cycle length variability during AF makes rate-corrected QT impossible to calculate. In this study, a newly developed method to study heart rate dependence of the QT interval during AF was applied to assess the QT-RR relationships prior to and following cardioversion in patients with AF. METHODS AND RESULTS Cardiac rhythm was digitized for > or = 30 minutes prior to and following elective cardioversion to sinus rhythm (SR) in 12 patients. Each QT interval was placed in a "bin" (50 ms), according to the preceding RR interval. All QT intervals within a bin were averaged and RR bin-specific QT values were derived. The slope of the QT-RR relationship was much flatter in AF (0.058 +/- 0.02) compared with that predicted by conventionally used QT rate corrections (0.130 [Bazett], 0.096 [Fridericia]) and much steeper after cardioversion (0.238 +/- 0.14, P < 0.01 compared with AF). The method also allowed us to establish that QT at any given RR interval prolonged when SR was restored (e.g., at RR interval 800 ms: QT = 0.38 +/- 0.03 second [AF] vs 0.46 +/- 0.05 second [SR], P < 0.01). The longest QT values were in patients receiving sotalol or quinidine. CONCLUSIONS The results of this study demonstrate that QT interval can be reliably measured in AF using a method that is independent of heart rate. We also showed that cardioversion of AF acutely increases the QT interval and the steepness of the QT-RR slope.
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Affiliation(s)
- Dawood Darbar
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tenneessee 37323-6602, USA.
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Abstract
PURPOSE OF REVIEW A wide array of drugs can cause marked QT prolongation with the associated risk of torsade de pointes. The large number of drugs with this potential, the correspondingly large number of patients exposed to such drugs, and the potentially fatal outcome make drug-induced long QT syndrome an important public health problem. This review focuses on mechanisms underlying QT prolongation and proarrhythmia, risk factors, including the role of genetic variants, and the unifying framework of reduced repolarization reserve. RECENT FINDINGS While most drugs that prolong the QT block a specific potassium channel, novel mechanisms altering protein trafficking have been discovered. The progression to torsade de pointes may be less related to degree of QT prolongation than to drug effects on transmural dispersion or variability of repolarization. Our understanding of certain predisposing risk factors has been further refined. SUMMARY Ongoing research continues to elucidate the mechanisms underlying drug-induced long QT syndrome. Importantly, studies are establishing improved predictors of risk for progression to torsade de pointes, in addition to the degree of QT prolongation, which is an imperfect predictor. Nonetheless, drug-induced long QT syndrome and torsade de pointes pose unique challenges for clinicians, researchers, drug-development programs, and regulatory agencies.
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Affiliation(s)
- Prince J Kannankeril
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
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47
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Abstract
This review summarizes the mechanistic properties and the recent experience in the development of a new antiarrhythmic agent, RSD1235 (recently named vernakalant), for the acute conversion of atrial fibrillation to sinus rhythm. Atrial fibrillation is the most common sustained cardiac arrhythmia that is observed in clinical practice and is associated with increased morbidity and mortality, resulting from stroke and exacerbation of heart failure. At present, there is a lack of pharmacologic agents that are able to safely and effectively convert the arrhythmia back to sinus rhythm. Vernakalant has the electrophysiologic properties of a multiple ion channel blocker, developed using a novel approach to target potassium channels that are selectively present in human atria rather than ventricles, and using a rate-dependent blocking strategy for its additional sodium channel block. This paper reviews the mechanism of action of this drug, its performance in preclinical models of efficacy and human disease, and its actions on patients in the completed and published preregistration clinical trials for vernakalant. Overall, vernakalant converted 51.5% of patients who had < 7 days duration of atrial fibrillation and it did this without significantly more cardiovascular adverse events than placebo. Therefore, it must be considered as an important new agent for the treatment of this growing health problem.
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Affiliation(s)
- David Fedida
- University of British Columbia, Department of Anesthesiology, Vancouver, British Columbia, Canada
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48
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Darpo B, Agin M, Kazierad DJ, Layton G, Muirhead G, Gray P, Jorkasky DK. Man versus machine: is there an optimal method for QT measurements in thorough QT studies? J Clin Pharmacol 2006; 46:598-612. [PMID: 16707406 DOI: 10.1177/0091270006286900] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Electrocardiographic (ECG) recordings from 3 placebo-controlled thorough QT healthy volunteer studies were used to compare QT intervals obtained by manual measurement with those generated by ECG machines. The effect of the positive control was compared to placebo at each time point for data obtained from both sources. Both manual and automated techniques consistently demonstrated statistically significant prolongation of QTcF with the positive controls. The proportion of outlier values was small for both methods. The pairwise comparison between manual and automated uncorrected QT intervals demonstrated clear differences, with intervals derived from one machine on average 16 to 19 milliseconds shorter and from the other 7 milliseconds longer than the manually measured QT intervals, but these differences disappeared when analyzing QT change from baseline. Both manual and automated, commercially available QT algorithms demonstrated small statistically significant effects on the QTc interval induced by positive controls.
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Affiliation(s)
- Borje Darpo
- MSc, Clinical Statistics, Clinical R and D, Pfizer Global Research and Development, Ramsgate Road, Sandwich, Kent, CT13 9NJ, United Kingdom
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Abstract
Individuals vary widely in their responses to therapy with most drugs. Indeed, responses to antiarrhythmic drugs are so highly variable that study of the underlying mechanisms has elucidated important lessons for understanding variable responses to drug therapy in general. Variability in drug response may reflect variability in the relationship between a drug dose and the concentrations of the drug and metabolite(s) at relevant target sites; this is termed pharmacokinetic variability. Another mechanism is that individuals vary in their response to identical exposures to a drug (pharmacodynamic variability). In this case, there may be variability in the target molecule(s) with which a drug interacts or, more generally, in the broad biological context in which the drug-target interaction occurs. Variants (polymorphisms and mutations) in the genes that encode proteins that are important for pharmacokinetics or for pharmacodynamics have now been described as important contributors to variable drug actions, including proarrhythmia, and these are described in this review. However, the translation of pharmacogenetics into clinical practice has been slow. To this end, the creation of large, well-characterised DNA databases and appropriate control groups, as well as large prospective trials to evaluate the impact of genetic variation on drug therapy, may hasten the impact of pharmacogenetics and pharmacogenomics in terms of delivering personalised drug therapy and to avoid therapeutic failure and serious side effects.
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Affiliation(s)
- Dawood Darbar
- Vanderbilt Arrhythmia Service, Vanderbilt University School of Medicine, Room 1285A, MRB IV, Nashville, TN 37323-6602, USA.
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50
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Abstract
The concept that antiarrhythmic drugs can exacerbate the cardiac rhythm disturbance being treated, or generate entirely new clinical arrhythmia syndromes, is not new. Abnormal cardiac rhythms due to digitalis or quinidine have been recognized for decades. This phenomenon, termed "proarrhythmia," was generally viewed as a clinical curiosity, since it was thought to be rare and unpredictable. However, the past 20 years have seen the recognition that proarrhythmia is more common than previously appreciated in certain populations, and can in fact lead to substantially increased mortality during long-term antiarrhythmic therapy. These findings, in turn, have moved proarrhythmia from a clinical curiosity to the centerpiece of antiarrhythmic drug pharmacology in at least two important respects. First, clinicians now select antiarrhythmic drug therapy in a particular patient not simply to maximize efficacy, but very frequently to minimize the likelihood of proarrhythmia. Second, avoiding proarrhythmia has become a key element of contemporary new antiarrhythmic drug development. Further, recognition of the magnitude of the problem has led to important advances in understanding basic mechanisms. While the phenomenon of proarrhythmia remains unpredictable in an individual patient, it can no longer be viewed as "idiosyncratic." Rather, gradations of risk can be assigned based on the current understanding of mechanisms, and these will doubtless improve with ongoing research at the genetic, molecular, cellular, whole heart, and clinical levels.
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Affiliation(s)
- D M Roden
- Division of Clinical Pharmacology, Vanderbilt University School of Medicine, 532 Medical Research Building I, Nashville, TN 37232, USA.
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