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Lancini D, Samuel M, Smith C, Wells G, Tang A, Parkash R. Delta QRS and outcomes post CRT in the Resynchronization-Defibrillation for Ambulatory Heart Failure Trial. Heart Rhythm 2024:S1547-5271(24)03426-X. [PMID: 39393749 DOI: 10.1016/j.hrthm.2024.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2024] [Revised: 09/30/2024] [Accepted: 10/04/2024] [Indexed: 10/13/2024]
Abstract
BACKGROUND Amongst patients with left ventricular systolic dysfunction and prolonged QRS duration, cardiac resynchronization therapy (CRT) can improve cardiac electromechanical synchrony, and prevent adverse clinical outcomes. OBJECTIVES To investigate the role of delta QRS duration (ΔQRSd) in predicting clinical response to CRT. METHODS The RAFT (Resynchronization-Defibrillation for Ambulatory Heart Failure Trial) study randomized 1798 patients to CRT with defibrillator or implantable cardioverter-defibrillator (ICD) alone. Those who received CRT and had electrocardiograms available at baseline and post CRT implantation were included in this analysis. ΔQRSd was calculated as the absolute difference between QRS duration at baseline and with CRT pacing. The primary outcome was the composite of death and heart failure hospitalization. RESULTS There were 813 patients included in this analysis. The median age was 67 years, and 125 patients (15.2%) were female. The median ΔQRSd was -2 ms (-20 to 18ms), and 447 (55%) of patients had a ΔQRSd ≤ 0 post implant. ΔQRSd was an independent predictor of the composite outcome amongst patients with CRT (HR = 1.012, 95% CI 1.008-1.017). CRT recipients with ΔQRSd > 0 had higher rates of the composite outcome than patients randomized to ICD alone. CONCLUSION Amongst patients receiving CRT for heart failure with left ventricular systolic dysfunction and QRS prolongation, ΔQRSd was an independent predictor of long-term mortality and heart failure hospitalization.
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Affiliation(s)
- Daniel Lancini
- Heart Rhythm Service, QEII Health Sciences Centre, Nova Scotia
| | | | - Corey Smith
- Heart Rhythm Service, QEII Health Sciences Centre, Nova Scotia
| | - George Wells
- University of Ottawa Heart Institute, Ottawa, Ontario
| | | | - Ratika Parkash
- Heart Rhythm Service, QEII Health Sciences Centre, Nova Scotia.
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2
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Shabtaie SA, Sehrawat O, Lee JZ, Cha Y, Mulpuru SK, Kowlgi NG, Siontis KC, Rosenbaum AN, Bois JP, AbouEzzeddine OF, Noseworthy PA, Asirvatham SJ, DeSimone CV, Deshmukh AJ. Cardiac Resynchronization Therapy Response in Cardiac Sarcoidosis. J Cardiovasc Electrophysiol 2022; 33:2072-2080. [DOI: 10.1111/jce.15631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/25/2022] [Accepted: 05/11/2022] [Indexed: 12/01/2022]
Affiliation(s)
- Samuel A. Shabtaie
- Department of Cardiovascular MedicineMayo Clinic200 First Street SWRochesterMN55905USA
| | - Ojasav Sehrawat
- Department of Cardiovascular MedicineMayo Clinic200 First Street SWRochesterMN55905USA
| | - Justin Z. Lee
- Department of Cardiovascular MedicineMayo Clinic200 First Street SWRochesterMN55905USA
| | - Yong‐Mei Cha
- Department of Cardiovascular MedicineMayo Clinic200 First Street SWRochesterMN55905USA
| | - Siva K. Mulpuru
- Department of Cardiovascular MedicineMayo Clinic200 First Street SWRochesterMN55905USA
| | - Narayan G. Kowlgi
- Department of Cardiovascular MedicineMayo Clinic200 First Street SWRochesterMN55905USA
| | | | - Andrew N. Rosenbaum
- Department of Cardiovascular MedicineMayo Clinic200 First Street SWRochesterMN55905USA
| | - John P. Bois
- Department of Cardiovascular MedicineMayo Clinic200 First Street SWRochesterMN55905USA
| | - Omar F. AbouEzzeddine
- Department of Cardiovascular MedicineMayo Clinic200 First Street SWRochesterMN55905USA
| | - Peter A. Noseworthy
- Department of Cardiovascular MedicineMayo Clinic200 First Street SWRochesterMN55905USA
| | - Samuel J. Asirvatham
- Department of Cardiovascular MedicineMayo Clinic200 First Street SWRochesterMN55905USA
| | | | - Abhishek J. Deshmukh
- Department of Cardiovascular MedicineMayo Clinic200 First Street SWRochesterMN55905USA
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3
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Lapidot D, Rav-Acha M, Bdolah-Abram T, Farkash R, Glikson M, Hasin T. QRS Narrowing Following CRT Implantation: Predictors, Dynamics, and Association with Improved Long-Term Outcome. J Clin Med 2022; 11:1279. [PMID: 35268370 PMCID: PMC8911497 DOI: 10.3390/jcm11051279] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 02/21/2022] [Accepted: 02/24/2022] [Indexed: 02/05/2023] Open
Abstract
Background: Heart failure (HF) patients with wide QRS often benefit from cardiac resynchronization therapy (CRT), although QRS narrowing does not always occur. The current study investigates the incidence and predictors for QRS narrowing following CRT and its long-term impact on clinical outcomes. Methods: Among individuals undergoing clinically indicated CRT, pre-and post-implantation electrocardiographs were meticulously analyzed for QRS duration change. All-cause mortality and the composite of mortality and HF hospitalizations were retrieved. Results: For 104 patients, mean age 67 years, 25% females, QRS narrowed within days by 20.2 ± 24.7 ms. In 55/104 (53%) QRS narrowed by ≥20 ms (“acute narrowing”). Female gender and baseline QRS predicted acute narrowing. Acute narrowing persisted for 1−6 weeks in 18/20 (90%) and 3−12 months in 21/31 (68%) of patients. During the average follow-up of 41 months, 29/104 (28%) died and 50/104 (48%) met the composite outcome. In a multivariable analysis including comorbidities and cardiac history, prolonged baseline PR interval (HR 1.015, CI 1.008−1.021, p < 0.001) and acute narrowing < 20 ms (HR 3.243, CI 1.593−6.603, p = 0.001) were significant and independent predictors for the composite outcome. Conclusions: Post-CRT acute QRS narrowing ≥ 20 ms is independently associated with favorable long-term outcomes and might be considered as a novel measure for procedural success.
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Affiliation(s)
- Daniel Lapidot
- Faculty of Medicine, Hebrew University, Jerusalem 9103102, Israel; (D.L.); (M.R.-A.); (T.B.-A.); (M.G.)
| | - Moshe Rav-Acha
- Faculty of Medicine, Hebrew University, Jerusalem 9103102, Israel; (D.L.); (M.R.-A.); (T.B.-A.); (M.G.)
- Jesselson Integrated Heart Center, Shaare Zedek Medical Center (SZMC), Jerusalem 9103102, Israel;
| | - Tali Bdolah-Abram
- Faculty of Medicine, Hebrew University, Jerusalem 9103102, Israel; (D.L.); (M.R.-A.); (T.B.-A.); (M.G.)
| | - Rivka Farkash
- Jesselson Integrated Heart Center, Shaare Zedek Medical Center (SZMC), Jerusalem 9103102, Israel;
| | - Michael Glikson
- Faculty of Medicine, Hebrew University, Jerusalem 9103102, Israel; (D.L.); (M.R.-A.); (T.B.-A.); (M.G.)
- Jesselson Integrated Heart Center, Shaare Zedek Medical Center (SZMC), Jerusalem 9103102, Israel;
| | - Tal Hasin
- Faculty of Medicine, Hebrew University, Jerusalem 9103102, Israel; (D.L.); (M.R.-A.); (T.B.-A.); (M.G.)
- Jesselson Integrated Heart Center, Shaare Zedek Medical Center (SZMC), Jerusalem 9103102, Israel;
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4
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Ma J, Liu Y, Dong Y, Chen M, Xia L, Xu M. Association between changes in QRS width and echocardiographic responses to cardiac resynchronization therapy: A systematic review and meta-analysis. Medicine (Baltimore) 2020; 99:e18684. [PMID: 31914066 PMCID: PMC6959877 DOI: 10.1097/md.0000000000018684] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Numerous studies have illustrated the association of QRS width with the incidence of echocardiographic response to cardiac resynchronization therapy (CRT). This study aimed to summarize the observational studies regarding the magnitude of change in QRS width between responders and nonresponders to CRT. METHODS The PubMed, Embase, and the Cochrane Library were systematically searched for relevant studies investigating the changes of QRS width with the incidence of echocardiographic response to CRT from inception till May 2019. The pooled weighted mean difference (WMD) with 95% confidence interval (CI) was calculated through random-effects model. RESULTS Five prospective and 6 retrospective studies with a total of 1524 patients were selected for final analysis. The reduction of QRS width in responders was significantly greater than nonresponders (WMD: -20.54 ms; 95% CI: -26.78 to -14.29; P < .001). Moreover, responders were associated with greater percentage reduction in QRS width when compared with nonresponders (WMD: -8.80%; 95% CI: -13.08 to -4.52; P < .001). Finally, the mean change in QRS width between responders and nonresponders differed when stratified by country, study design, mean age, percentage male, ejection fraction, measuring time of postimplanted QRS, ischemic cardiomyopathy, atrial fibrillation, and study quality. CONCLUSIONS These findings indicated that shortening QRS width after CRT device implantation showed association with greater incidence of echocardiographic responses to CRT. Further prospective studies should be conducted to evaluate the prognostic values of QRS width on the incidence of echocardiographic response to CRT.
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Affiliation(s)
- Jing Ma
- Division of Cardiology, Xuhui Central Hospital, Zhongshan-Xuhui Hospital, Fudan University
| | - Yi Liu
- Department of Ultrasonography, Shuguang Hospital, University of Traditional Chinese Medicine
| | - Yun Dong
- Department of Ultrasonography, East Hospital, Tongji University, Shanghai, China
| | - Ming Chen
- Department of Ultrasonography, East Hospital, Tongji University, Shanghai, China
| | - Lianghua Xia
- Department of Ultrasonography, East Hospital, Tongji University, Shanghai, China
| | - Min Xu
- Department of Ultrasonography, East Hospital, Tongji University, Shanghai, China
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5
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Harb SC, Toro S, Bullen JA, Obuchowski NA, Xu B, Trulock KM, Varma N, Rickard J, Grimm R, Griffin B, Flamm SD, Kwon DH. Scar burden is an independent and incremental predictor of cardiac resynchronisation therapy response. Open Heart 2019; 6:e001067. [PMID: 31354957 PMCID: PMC6615837 DOI: 10.1136/openhrt-2019-001067] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 05/01/2019] [Accepted: 05/30/2019] [Indexed: 01/07/2023] Open
Abstract
Objective Determine the prognostic impact of scar quantification (scar %) by cardiac magnetic resonance (CMR) in predicting heart failure admission, death and left ventricular (LV) function improvement following cardiac resynchronisation therapy (CRT), after controlling for the presence of left bundle branch block (LBBB), QRS duration (QRSd) and LV lead tip location and polarity. Methods Consecutive patients who underwent CMR between 2002 and 2014 followed by CRT were included. The primary endpoint was death or heart failure admission. The secondary endpoint was change in ejection fraction (EF) ≥3 months after CRT. Cox proportional hazards, linear regression models and change in the area under the receiver operating characteristic curve (AUC) were used. Results A total of 84 patients were included (63% male, 51% with ischaemic cardiomyopathy). After adjusting for clinical factors, presence of LBBB and QRSd and LV lead tip location and polarity, greater scar % remained associated with a higher risk for clinical events (HR=1.06; 95% CI 1.02 to 1.10; p<0.001) and a smaller improvement in EF (slope: −0.61%; 95% CI −0.93% to 0.29%; p<0.001). When adding scar % to QRSd and LBBB, there was significant improvement in predicting clinical events at 3 years (AUC increased to 0.831 from 0.638; p=0.027) and EF increase ≥10% (AUC 0.869 from 0.662; p=0.007). Conclusion Scar quantification by CMR has an incremental value in predicting response to CRT, in terms of heart failure admission, death and EF improvement, independent of the presence of LBBB, QRSd, LV lead tip location and polarity.
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Affiliation(s)
- Serge C Harb
- Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Saleem Toro
- Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Jennifer A Bullen
- Quantitative Health Sciences, Cleveland Clinic, Cleveland, Ohio, USA
| | | | - Bo Xu
- Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Kevin M Trulock
- Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Niraj Varma
- Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - John Rickard
- Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Richard Grimm
- Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Brian Griffin
- Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA.,Quantitative Health Sciences, Cleveland Clinic, Cleveland, Ohio, USA
| | - Scott D Flamm
- Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Deborah H Kwon
- Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio, USA
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6
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Jastrzębski M, Baranchuk A, Fijorek K, Kisiel R, Kukla P, Sondej T, Czarnecka D. Cardiac resynchronization therapy-induced acute shortening of QRS duration predicts long-term mortality only in patients with left bundle branch block. Europace 2018; 21:281-289. [DOI: 10.1093/europace/euy254] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 10/11/2018] [Indexed: 11/14/2022] Open
Affiliation(s)
- Marek Jastrzębski
- First Department of Cardiology, Interventional Electrocardiology and Hypertension, Jagiellonian University, Medical College, Kopernika str. 17, Krakow 31-052, Poland
| | - Adrian Baranchuk
- Heart Rhythm Service, Kingston Heart Sciences Center, Kingston, ON, Canada
| | - Kamil Fijorek
- Department of Statistics, Cracow University of Economics, Krakow, Poland
| | - Roksana Kisiel
- First Department of Cardiology, Interventional Electrocardiology and Hypertension, Jagiellonian University, Medical College, Kopernika str. 17, Krakow 31-052, Poland
| | - Piotr Kukla
- Department of Cardiology, H. Klimontowicz Specialistic Hospital, Gorlice, Poland
| | - Tomasz Sondej
- First Department of Cardiology, Interventional Electrocardiology and Hypertension, Jagiellonian University, Medical College, Kopernika str. 17, Krakow 31-052, Poland
| | - Danuta Czarnecka
- First Department of Cardiology, Interventional Electrocardiology and Hypertension, Jagiellonian University, Medical College, Kopernika str. 17, Krakow 31-052, Poland
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7
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Abstract
PURPOSE OF REVIEW This review focuses on the current advancements in optimizing patient response to cardiac resynchronization therapy (CRT). RECENT FINDINGS It has been well known that not every patient will derive benefit from CRT, and of those that do, there are varying levels of response. Optimizing CRT begins well before device implant and involves appropriate patient selection and an understanding of the underlying substrate. After implant, there are different CRT device programming options that can be enabled to help overcome barriers as to why a patient may not respond. Given the multifaceted components of optimizing CRT and the complex patient population, multi-subspecialty clinics have been developed bringing together specialists in heart failure, electrophysiology, and imaging. Data as to whether this results in better response rates and outcomes shows promise.
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8
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Daubert C, Behar N, Martins RP, Mabo P, Leclercq C. Avoiding non-responders to cardiac resynchronization therapy: a practical guide. Eur Heart J 2018; 38:1463-1472. [PMID: 27371720 DOI: 10.1093/eurheartj/ehw270] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 06/02/2016] [Indexed: 01/14/2023] Open
Abstract
Over two decades after the introduction of cardiac resynchronization therapy (CRT) into clinical practice, ∼30% of candidates continue to fail to respond to this highly effective treatment of drug-refractory heart failure (HF). Since the causes of this non-response (NR) are multifactorial, it will require multidisciplinary efforts to overcome. Progress has, thus far, been slowed by several factors, ranging from a lack of consensus regarding the definition of NR and technological limitations to the delivery of therapy. We critically review the various endpoints that have been used in landmark clinical trials of CRT, and the variability in response rates that has been observed as a result of these different investigational designs, different sample populations enrolled and different means of therapy delivered, including new means of multisite and left ventricular endocardial simulation. Precise recommendations are offered regarding the optimal device programming, use of telemonitoring and optimization of management of HF. Potentially reversible causes of NR to CRT are reviewed, with emphasis on loss of biventricular stimulation due to competing arrhythmias. The prevention of NR to CRT is essential to improve the overall performance of this treatment and lower its risk-benefit ratio. These objectives require collaborative efforts by the HF team, the electrophysiologists and the cardiac imaging experts.
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Affiliation(s)
- Claude Daubert
- School of medicine, Rennes 1 University, Rennes, France.,LTSI INSERM U1099, Rennes, France
| | - Nathalie Behar
- Cardiology and vascular diseases Division, Rennes University Hospital, Rennes, France
| | - Raphaël P Martins
- School of medicine, Rennes 1 University, Rennes, France.,LTSI INSERM U1099, Rennes, France.,Cardiology and vascular diseases Division, Rennes University Hospital, Rennes, France
| | - Philippe Mabo
- School of medicine, Rennes 1 University, Rennes, France.,LTSI INSERM U1099, Rennes, France.,Cardiology and vascular diseases Division, Rennes University Hospital, Rennes, France
| | - Christophe Leclercq
- School of medicine, Rennes 1 University, Rennes, France.,LTSI INSERM U1099, Rennes, France.,Cardiology and vascular diseases Division, Rennes University Hospital, Rennes, France
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9
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Varma N, O'Donnell D, Bassiouny M, Ritter P, Pappone C, Mangual J, Cantillon D, Badie N, Thibault B, Wisnoskey B. Programming Cardiac Resynchronization Therapy for Electrical Synchrony: Reaching Beyond Left Bundle Branch Block and Left Ventricular Activation Delay. J Am Heart Assoc 2018; 7:e007489. [PMID: 29432133 PMCID: PMC5850248 DOI: 10.1161/jaha.117.007489] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 11/30/2017] [Indexed: 11/16/2022]
Abstract
BACKGROUND QRS narrowing following cardiac resynchronization therapy with biventricular (BiV) or left ventricular (LV) pacing is likely affected by patient-specific conduction characteristics (PR, qLV, LV-paced propagation interval), making a universal programming strategy likely ineffective. We tested these factors using a novel, device-based algorithm (SyncAV) that automatically adjusts paced atrioventricular delay (default or programmable offset) according to intrinsic atrioventricular conduction. METHODS AND RESULTS Seventy-five patients undergoing cardiac resynchronization therapy (age 66±11 years; 65% male; 32% with ischemic cardiomyopathy; LV ejection fraction 28±8%; QRS duration 162±16 ms) with intact atrioventricular conduction (PR interval 194±34, range 128-300 ms), left bundle branch block, and optimized LV lead position were studied at implant. QRS duration (QRSd) reduction was compared for the following pacing configurations: nominal simultaneous BiV (Mode I: paced/sensed atrioventricular delay=140/110 ms), BiV+SyncAV with 50 ms offset (Mode II), BiV+SyncAV with offset that minimized QRSd (Mode III), or LV-only pacing+SyncAV with 50 ms offset (Mode IV). The intrinsic QRSd (162±16 ms) was reduced to 142±17 ms (-11.8%) by Mode I, 136±14 ms (-15.6%) by Mode IV, and 132±13 ms (-17.8%) by Mode II. Mode III yielded the shortest overall QRSd (123±12 ms, -23.9% [P<0.001 versus all modes]) and was the only configuration without QRSd prolongation in any patient. QRS narrowing occurred regardless of QRSd, PR, or LV-paced intervals, or underlying ischemic disease. CONCLUSIONS Post-implant electrical optimization in already well-selected patients with left bundle branch block and optimized LV lead position is facilitated by patient-tailored BiV pacing adjusted to intrinsic atrioventricular timing using an automatic device-based algorithm.
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Affiliation(s)
| | | | | | | | - Carlo Pappone
- Department of Electrophysiology, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | | | | | | | - Bernard Thibault
- Electrophysiology Service, Montreal Heart Institute, Montreal, Canada
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10
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De Pooter J, El Haddad M, Stroobandt R, De Buyzere M, Timmermans F. Accuracy of computer-calculated and manual QRS duration assessments: Clinical implications to select candidates for cardiac resynchronization therapy. Int J Cardiol 2017; 236:276-282. [DOI: 10.1016/j.ijcard.2017.01.129] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 01/24/2017] [Accepted: 01/27/2017] [Indexed: 12/28/2022]
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11
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Linde C, Abraham WT, Gold MR, Daubert JC, Tang ASL, Young JB, Sherfesee L, Hudnall JH, Fagan DH, Cleland JG. Predictors of short-term clinical response to cardiac resynchronization therapy. Eur J Heart Fail 2017; 19:1056-1063. [PMID: 28295869 DOI: 10.1002/ejhf.795] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 01/24/2017] [Accepted: 01/30/2017] [Indexed: 12/28/2022] Open
Abstract
AIMS Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in patients with symptomatic heart failure and QRS prolongation but there is uncertainty about which patient characteristics predict short-term clinical response. METHODS AND RESULTS In an individual patient meta-analysis of three double-blind, randomized trials, clinical composite score (CCS) at 6 months was compared in patients assigned to CRT programmed on or off. Treatment-covariate interactions were assessed to measure likelihood of improved CCS at 6 months. MIRACLE, MIRACLE ICD, and REVERSE trials contributed data for this analysis (n = 1591). Multivariable modelling identified QRS duration and left ventricular ejection fraction (LVEF) as predictors of CRT clinical response (P < 0.05). The odds ratio for a better CCS at 6 months increased by 3.7% for every 1% decrease in LVEF for patients assigned to CRT-on compared to CRT-off, and was greatest when QRS duration was between 160 and 180 ms. CONCLUSIONS In symptomatic chronic heart failure patients (NYHA class II-IV), longer QRS duration and lower LVEF independently predict early clinical response to CRT.
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Affiliation(s)
- Cecilia Linde
- Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden
| | - William T Abraham
- Division of Cardiovascular Medicine and the Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Michael R Gold
- Medical University of South Carolina, Charleston, SC, USA
| | | | - Anthony S L Tang
- The Island Medical Program, University of British Columbia, Vancouver, Canada
| | - James B Young
- Cleveland Clinic Lerner College of Medicine, Cleveland, OH, USA
| | | | | | | | - John G Cleland
- National Heart and Lung Institute, Imperial College London, London, UK
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12
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DE Pooter J, El Haddad M, DE Buyzere M, Aranda HA, Cornelussen R, Stegemann B, Rinaldi CA, Sterlinski M, Sokal A, Francis DP, Jordaens L, Stroobandt RX, VAN Heuverswyn F, Timmermans F. Biventricular Paced QRS Area Predicts Acute Hemodynamic CRT Response Better Than QRS Duration or QRS Amplitudes. J Cardiovasc Electrophysiol 2016; 28:192-200. [PMID: 27885752 DOI: 10.1111/jce.13132] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 10/20/2016] [Accepted: 11/14/2016] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Vectorcardiographic (VCG) QRS area of left bundle branch block (LBBB) predicts acute hemodynamic response in cardiac resynchronization therapy (CRT) patients. We hypothesized that changes in QRS area occurring with biventricular pacing (BV) might predict acute hemodynamic CRT response (AHR). METHODS AND RESULTS VCGs of 624 BV paced electrocardiograms (25 LBBB patients with 35 different pacing configurations) were calculated according to Frank's orthogonal lead system. Maximum QRS vector amplitudes (XAmpl , YAmpl , ZAmpl , and 3DAmp ) and QRS areas (XArea , YArea , ZArea , and 3DArea ) in the orthogonal leads (X, Y, and Z) and in 3-dimensional projection were measured. Volume of the 3D vector loop and global QRS duration (QRSD) on the surface electrocardiogram were assessed. Differences (Δ) in VCG parameters between BV paced and LBBB QRS complexes were calculated. An increase of 10% in dP/dt max was considered as AHR. LBBB conduction is characterized by a large ZArea (109 μVs, interquartile range [IQR]:75;135), significantly larger than XArea (22 μVs, IQR:10;57) and YArea (44 μVs, IQR:32;62, P < 0.001). Overall, QRS duration, amplitudes, and areas decrease significantly with BV pacing (P < 0.001). Of all VCG parameters, 3DAmpl , Δ3DAmpl , ZArea, ΔZArea , Δ3DArea , and ΔQRSD differentiate AHR response from nonresponse (P < 0.05). ΔZArea predicted best positive AHR (area under the curve = 0.813) and outperformed any other VCG parameter or QRSD measurement. CONCLUSION Of all VCG parameters, reduction in QRS area, calculated in Frank's Z lead, predicts acute hemodynamic response best. This method might be an easy, noninvasive tool to guide CRT implantation and optimization.
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Affiliation(s)
- Jan DE Pooter
- Ghent University Hospital, Heart Center, Ghent, Belgium
| | | | | | | | | | | | | | - Maciej Sterlinski
- The Second Department of Coronary Artery Disease, Institute of Cardiology, Warsaw, Poland
| | - Adam Sokal
- Department of Cardiology, Congenital Heart Diseases and Electrotherapy Silesian Center of Heart Disease, Zabrze, Poland
| | - Darrel P Francis
- Faculty of Medicine, Imperial College Healthcare NHS Trust, London, England, UK
| | - Luc Jordaens
- Ghent University Hospital, Heart Center, Ghent, Belgium
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13
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Korantzopoulos P, Zhang Z, Li G, Fragakis N, Liu T. Meta-Analysis of the Usefulness of Change in QRS Width to Predict Response to Cardiac Resynchronization Therapy. Am J Cardiol 2016; 118:1368-1373. [PMID: 27634027 DOI: 10.1016/j.amjcard.2016.07.070] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/28/2016] [Accepted: 07/28/2016] [Indexed: 10/21/2022]
Abstract
The existing data regarding the role of QRS duration (QRSd) change on cardiac resynchronization therapy (CRT) response show some inconsistent results. We conducted a meta-analysis of data obtained from observational studies to examine the impact of QRS change after CRT device implantation on the clinical and/or echocardiographic response. We searched the PubMed and EMBASE databases for relevant studies published before January 2016. Twenty-seven studies were retrieved for detailed evaluation of which 12 studies with a total population of 1,545 patients met our eligibility criteria. The analysis demonstrated that QRSd narrowing was a positive predictor of response to CRT (mean difference [MD] = -19.24 ms, 95% CI = -24.00 to -14.48 ms, p <0.00001). This effect was consistent in the studies using clinical criteria (MD = -19.91 ms, 95% CI = -27.20 to -12.62 ms, p <0.00001) and in those that used echocardiographic criteria (MD = -19.51 ms, 95% CI = -25.78 to -13.25 ms, p <0.00001). The heterogeneity test showed moderate differences among the individual studies (I2 = 42%). Subgroup analysis showed that QRSd change was more pronounced in studies having a follow-up ≤6 months. We did not find significant differences in studies measuring postimplantation QRSd after a certain follow-up period compared with studies measuring QRSd immediately after CRT device implantation. Further studies should clarify the exact timing of QRSd assessments during follow-up. In conclusion, QRSd shortening after CRT device implantation is associated with a favorable clinical and echocardiographic response.
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Magnitude of QRS duration reduction after biventricular pacing identifies responders to cardiac resynchronization therapy. Int J Cardiol 2016; 221:450-5. [PMID: 27414720 DOI: 10.1016/j.ijcard.2016.06.203] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 05/12/2016] [Accepted: 06/25/2016] [Indexed: 11/21/2022]
Abstract
BACKGROUND Several studies have investigated the association between native QRS duration (QRSd) or QRS narrowing and response to biventricular pacing. However, their results have been conflicting. The aim of our study was to determine the association between the relative change in QRS narrowing index (QI) and clinical outcome and prognosis in patients who undergo cardiac resynchronization therapy (CRT) implantation. METHODS AND RESULTS We included 311 patients in whom a CRT device was implanted in accordance with current guidelines for CRT. On implantation, the native QRS, the QRSd and the QI during CRT were measured. After 6months, 220 (71%) patients showed a 10% reduction in LVESV. The median [25th-75th] QI was 14.3% [7.2-21.4] and was significantly related to reverse remodeling (r=+0.22; 95%CI: 0.11-0.32, p=0.0001). The cut-off value of QI that best predicted LV reverse remodeling after 6months of CRT was 12.5% (sensitivity=63.6%, specificity=57.1%, area under the curve=0.633, p=0.0002). The time to the event death or cardiovascular hospitalization was significantly longer among patients with QI>12.5% (log-rank test, p=0.0155), with a hazard ratio (HR) of 0.3 [95%CI: 0.11-0.78]. In the multivariate regression model adjusted for baseline parameters, a 10% increment in QI (HR=0.61[0.44-0.83], p=0.002) remained significantly associated with CRT response. CONCLUSIONS Patients with a larger decrease in QRSd after CRT initiation showed greater echocardiographic reverse remodeling and better outcome from death or cardiovascular hospitalization. QI is an easy-to-measure variable that could be used to predict CRT response at the time of pacing site selection or pacing configuration programming.
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De Pooter J, El Haddad M, Timmers L, Van Heuverswyn F, Jordaens L, Duytschaever M, Stroobandt R. Different Methods to Measure QRS Duration in CRT Patients: Impact on the Predictive Value of QRS Duration Parameters. Ann Noninvasive Electrocardiol 2015; 21:305-15. [PMID: 26391903 DOI: 10.1111/anec.12313] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Measurements of QRS duration (QRSD) in patients undergoing cardiac resynchronization therapy (CRT) are not standardized. We hypothesized that both the measurement of QRSD and its predictive value on CRT response are sensitive to the method by which QRSD is measured. METHODS Electrocardiograms (ECGs) pre- and post-CRT from 52 CRT patients (66 ± 12 years, 65% male) were retrospectively analyzed. Custom-made software was developed to measure global QRSD (QRSDglobal ) and lead-specific QRSD (QRSDI,II,III,aVR,aVL,aVF,V1,V2,V3,V4,V5,V6 ). QRSD was also assessed automatic by a routinely used ECG device. For each method we measured QRSD pre- and post-CRT and shortening of QRSD (∆QRSD). Response to CRT at 6 months was defined as an improvement of ≥1 class in New York Heart Association classification and an increase by >7.5% in left ventricular ejection fraction. RESULTS The CRT response rate was 77% (n = 40). Different methods to measure QRSD show divergent nominal values before (median range 152-172 ms, P < 0.001) and after CRT (130-152 ms, P < 0.001). The predictive value of QRSD measurements for CRT response also varies significantly according to the method used (range AUC pre-CRT QRSD 0.400-0.580, P < 0.05; AUC post-CRT QRSD 0.447-0.768, P < 0.05; AUC ΔQRSD 0.540-0.858, P < 0.05). Global QRSD measurements revealed lower variability compared to lead-specific QRSD. CONCLUSION Different methods to measure QRSD yield not only different nominal values but also influence the value of QRSD in predicting CRT response. Measuring QRSD by a global method can help to standardize QRSD measurements in future studies.
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Affiliation(s)
- Jan De Pooter
- Ghent University Hospital, Heart Center, Ghent, Belgium
| | | | | | | | - Luc Jordaens
- Ghent University Hospital, Heart Center, Ghent, Belgium
| | - Mattias Duytschaever
- Ghent University Hospital, Heart Center, Ghent, Belgium.,Department of Cardiology, Sint-Jan Hospital, Bruges, Belgium
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Varma N. Left ventricular electrical activation during right ventricular pacing in heart failure patients with LBBB: Visualization by electrocardiographic imaging and implications for cardiac resynchronization therapy. J Electrocardiol 2015; 48:53-61. [DOI: 10.1016/j.jelectrocard.2014.09.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Indexed: 11/16/2022]
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17
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Progressive ventricular dysfunction among nonresponders to cardiac resynchronization therapy: Baseline predictors and associated clinical outcomes. Heart Rhythm 2014; 11:1991-8. [DOI: 10.1016/j.hrthm.2014.08.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Indexed: 11/24/2022]
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Yang XW, Hua W, Wang J, Liu ZM, Ding LG, Chen KP, Zhang S. Native QRS narrowing reflects electrical reversal and associates with anatomical reversal in cardiac resynchronization therapy. J Interv Card Electrophysiol 2014; 41:161-8. [DOI: 10.1007/s10840-014-9936-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 07/01/2014] [Indexed: 10/24/2022]
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Yang XW, Hua W, Wang J, Liu ZM, Ding LG, Chen KP, Zhang S. Regression of fragmented QRS complex: a marker of electrical reverse remodeling in cardiac resynchronization therapy. Ann Noninvasive Electrocardiol 2014; 20:18-27. [PMID: 25040593 DOI: 10.1111/anec.12172] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Fragmented QRS (fQRS) marks inhomogeneous activation and asynchronous cardiac contraction. It has been proved that cardiac resynchronization therapy (CRT) could reverse geometrical remodeling as well as correct electrical dyssynchrony. We aimed to investigate whether fQRS changed corresponding to the therapeutic response to CRT. METHODS Patients who underwent de novo CRT implantation previously and had ≥1 follow-up between August 2012 and September 2013 in our hospital were investigated. Intrinsic electrocardiogram was recorded and fQRS in any lead was calculated. Response to CRT was defined as absolute improvement in left ventricular ejection fraction by ≥10% or by improvement >1 New York Heart Association class and without heart failure hospitalization. RESULTS A total of 75 patients (48 male, mean ages, 61 ± 9 years) were included in this study. At a median follow-up of 13 months, 57 patients had response to CRT. Responders had narrowed QRS (from 167 ± 23 ms to 158 ± 19 ms, P = 0.003) and reduced fQRS post-CRT. Nonresponders had QRS prolonging (from 151 ± 26 ms to 168 ± 16 ms, P = 0.033) and increase in fQRS. Eleven of 12 patients with reduced fQRS were responders and 8 of 12 with increased fQRS were nonresponders. Both changes in QRS and fQRS correlated strongly with CRT response (r = 0.389, P = 0.001 and r = 0.403, P = 0.000, respectively). Reduction of fQRS in ≥1 leads had high specificity (95%) in association to responders, though in low sensitivity (19%). CONCLUSIONS The changes in fQRS associated with therapeutic response to CRT. Regression of fQRS could be a maker of electrical reverse remodeling following CRT.
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Affiliation(s)
- Xin-wei Yang
- Center of Arrhythmia Diagnosis and Treatment, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Stabile G, Iuliano A, La Rocca V, Solimene F, Fazio R, De Simone A. Geometrical and electrical predictors of cardiac resynchronization therapy response. Expert Rev Cardiovasc Ther 2014; 12:873-84. [PMID: 24849323 DOI: 10.1586/14779072.2014.921117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Giuseppe Stabile
- Laboratorio di Elettrofisiologia, Clinica Mediterranea, Via Orazio 2, 80122, Napoli, Italy
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Periprocedural Management of Cardiac Resynchronization Therapy. CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2014; 16:298. [DOI: 10.1007/s11936-014-0298-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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22
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Varma N. Variegated left ventricular electrical activation in response to a novel quadripolar electrode: Visualization by non-invasive electrocardiographic imaging. J Electrocardiol 2014; 47:66-74. [DOI: 10.1016/j.jelectrocard.2013.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Indexed: 10/26/2022]
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Cleland JG, Abraham WT, Linde C, Gold MR, Young JB, Claude Daubert J, Sherfesee L, Wells GA, Tang AS. An individual patient meta-analysis of five randomized trials assessing the effects of cardiac resynchronization therapy on morbidity and mortality in patients with symptomatic heart failure. Eur Heart J 2013; 34:3547-56. [PMID: 23900696 PMCID: PMC3855551 DOI: 10.1093/eurheartj/eht290] [Citation(s) in RCA: 385] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 06/24/2013] [Accepted: 07/04/2013] [Indexed: 12/25/2022] Open
Abstract
AIMS Cardiac resynchronization therapy (CRT) with or without a defibrillator reduces morbidity and mortality in selected patients with heart failure (HF) but response can be variable. We sought to identify pre-implantation variables that predict the response to CRT in a meta-analysis using individual patient-data. METHODS AND RESULTS An individual patient meta-analysis of five randomized trials, funded by Medtronic, comparing CRT either with no active device or with a defibrillator was conducted, including the following baseline variables: age, sex, New York Heart Association class, aetiology, QRS morphology, QRS duration, left ventricular ejection fraction (LVEF), and systolic blood pressure. Outcomes were all-cause mortality and first hospitalization for HF or death. Of 3782 patients in sinus rhythm, median (inter-quartile range) age was 66 (58-73) years, QRS duration was 160 (146-176) ms, LVEF was 24 (20-28)%, and 78% had left bundle branch block. A multivariable model suggested that only QRS duration predicted the magnitude of the effect of CRT on outcomes. Further analysis produced estimated hazard ratios for the effect of CRT on all-cause mortality and on the composite of first hospitalization for HF or death that suggested increasing benefit with increasing QRS duration, the 95% confidence bounds excluding 1.0 at ∼140 ms for each endpoint, suggesting a high probability of substantial benefit from CRT when QRS duration exceeds this value. CONCLUSION QRS duration is a powerful predictor of the effects of CRT on morbidity and mortality in patients with symptomatic HF and left ventricular systolic dysfunction who are in sinus rhythm. QRS morphology did not provide additional information about clinical response. CLINICALTRIALSGOV NUMBERS NCT00170300, NCT00271154, NCT00251251.
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Affiliation(s)
- John G. Cleland
- National Heart and Lung Institute, Imperial College London (Royal Brompton & Harefield Hospitals) and Department of Cardiology, Castle Hill Hospital, University of Hull, Kingston-upon-Hull, UK
| | - William T. Abraham
- Division of Cardiovascular Medicine and the Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Cecilia Linde
- Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden
| | | | - James B. Young
- Cleveland Clinic Lerner College of Medicine, Cleveland, OH, USA
| | | | | | | | - Anthony S.L. Tang
- The Island Medical Program, University of British Columbia, Vancouver, Canada
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Chen Z, Hanson B, Sohal M, Sammut E, Child N, Shetty A, Boucher R, Bostock J, Gill J, Carr-White G, Rinaldi CA, Taggart P. Left Ventricular Epicardial Electrograms Show Divergent Changes in Action Potential Duration in Responders and Nonresponders to Cardiac Resynchronization Therapy. Circ Arrhythm Electrophysiol 2013; 6:265-71. [DOI: 10.1161/circep.112.000148] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Zhong Chen
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Ben Hanson
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Manav Sohal
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Eva Sammut
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Nick Child
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Anoop Shetty
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Ryan Boucher
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Julian Bostock
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Jaswinder Gill
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Gerald Carr-White
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - C. Aldo Rinaldi
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Peter Taggart
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
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Jastrzebski M, Wiliński J, Fijorek K, Sondej T, Czarnecka D. Mortality and morbidity in cardiac resynchronization patients: impact of lead position, paced left ventricular QRS morphology and other characteristics on long-term outcome. ACTA ACUST UNITED AC 2012; 15:258-65. [DOI: 10.1093/europace/eus340] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Daubert JC, Martins RP, Leclercq C. Predictive value of QRS changes after cardiac resynchronization therapy. Heart Rhythm 2012; 9:1679-80. [DOI: 10.1016/j.hrthm.2012.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Indexed: 11/25/2022]
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