Sustained clinical benefit of cardiac resynchronization therapy in non-LBBB patients with prolonged PR-interval: MADIT-CRT long-term follow-up.
OBJECTIVE
In MADIT-CRT, patients with non-LBBB (right bundle branch block or nonspecific ventricular conduction delay) and a prolonged PR-interval derived significant clinical benefit from cardiac resynchronization therapy with defibrillator (CRT-D) compared to an implantable cardioverter defibrillator (ICD)-only. We aimed to study the long-term outcome of non-LBBB patients by baseline PR-interval with CRT-D versus ICD-only.


METHODS
Non-LBBB patients (n = 534) were dichotomized based on baseline PR-interval: normal PR (PR < 230 ms), and markedly prolonged PR (PR ≥ 230 ms). The primary end point was heart failure (HF) or death. Secondary end points were HF only and all-cause death.


RESULTS
In patients with a prolonged PR-interval, CRT-D treatment related to a 67 % significant reduction in the risk of HF/death (HR = 0.33, 95 % CI 0.16-0.69, p = 0.003), 69 % decrease in HF (HR = 0.31, 95 % CI 0.14-0.68, p = 0.003), and 76 % reduction in the risk of death (HR = 0.24, 95 % CI 0.07-0.80, p = 0.020) compared to ICD-only (median follow-up 5.8 years). In normal PR-interval patients, CRT-D therapy was associated with a trend towards increased risk of HF/death (HR = 1.49, 95 % CI 0.98-2.25, p = 0.061), and significantly increased mortality (HR = 2.27, 95 % CI 1.16-4.44, p = 0.014). Significant statistical interaction with the PR-interval was demonstrated for all end points. Results were consistent for QRS 130-150 ms and QRS > 150 ms.


CONCLUSIONS
In MADIT-CRT, non-LBBB patients with a prolonged PR-interval derive sustained long-term clinical benefit with reductions in heart failure or death from CRT-D implantation, compared to an ICD-only. Our findings support implantation of CRT-D in non-LBBB patients with prolonged PR-interval irrespective of baseline QRS duration.
Department Cardiology & Angiology, Charité University Hospital, Berlin, Germany.|Department of Cardiology, Havelland Kliniken, Nauen, Germany.
Martin
M
Stockburger
Heart Research Follow-Up Program, University of Rochester Medical Center, Rochester, NY, USA.
Arthur J
AJ
Moss
Heart Research Follow-Up Program, University of Rochester Medical Center, Rochester, NY, USA.
Helmut U
HU
Klein
Heart Research Follow-Up Program, University of Rochester Medical Center, Rochester, NY, USA.
Wojciech
W
Zareba
Heart Research Follow-Up Program, University of Rochester Medical Center, Rochester, NY, USA.
Ilan
I
Goldenberg
Heart Research Follow-Up Program, University of Rochester Medical Center, Rochester, NY, USA.
Yitschak
Y
Biton
Heart Research Follow-Up Program, University of Rochester Medical Center, Rochester, NY, USA.
Scott
S
McNitt
Heart Research Follow-Up Program, University of Rochester Medical Center, Rochester, NY, USA. Valentina.Kutyifa@heart.rochester.edu.
Valentina
V
Kutyifa
D000200:Action Potentials; D000368:Aged; D054537:Atrioventricular Block / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D002037:Bundle-Branch Block / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000401:mortality; D058409:Cardiac Resynchronization Therapy Devices; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000009:adverse effects / Q000295:instrumentation / Q000401:mortality; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000209:etiology; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D012042:Registries; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
Cardiac resynchronization therapy; First-degree AV block; Left bundle branch block; MADIT-CRT; Non-left bundle branch block; PR-interval