Time-dependent risk reduction of ventricular tachyarrhythmias in cardiac resynchronization therapy patients: a MADIT-RIT sub-study

Document Type

Article

Publication Date

7-1-2015

Publication Title

Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology

Keywords

Age Distribution, Aged, Aged, 80 and over, Cardiac Resynchronization Therapy, Defibrillators, Implantable, Disease-Free Survival, Female, Humans, Male, Middle Aged, Survival Analysis, Tachycardia, Ventricular, Treatment Outcome, United States, Ventricular Fibrillation

Abstract

AIMS: Data on the time-dependent benefit of cardiac resynchronization therapy with defibrillator (CRT-D) compared with a dual-chamber implantable cardioverter-defibrillator (ICD) to reduce death or ventricular tachycardia (VT) or ventricular fibrillation (VF) are limited. We aimed to evaluate the time-related risk of death or sustained VT or VF in patients receiving CRT-D vs. ICD in the MADIT-RIT trial.

METHODS AND RESULTS: Kaplan-Meier survival analyses and multivariate Cox regression models were utilized to compare the incidence and the risk of death or sustained VT/VF in the CRT-D and ICD subgroups by the elapsed time after device implantation (6 months). Of the ICD (n = 742) and CRT-D (n = 757) patients enrolled, the risk of death was lower in CRT-D vs. in ICD early after device implantation [hazard ratio (HR) = 0.42, 95% confidence interval (CI): 0.17-1.03, P = 0.058] and beyond 6 months of follow-up (HR = 0.39, 95% CI: 0.21-0.73, P = 0.004), with the 6-month interaction P = 0.899. The overall risk of sustained VT/VF was reduced in CRT-D vs. ICD patients (HR = 0.73, 95% CI: 0.52-1.03, P = 0.07). However, the risk was similar in the first 6 months (HR = 1.00, 95% CI: 0.62-1.62, P = 0.988), and a lower risk emerged 6 months after CRT-D implantation (HR = 0.58, 95% CI: 0.38-0.88, P = 0.011), with the 6-month interaction P = 0.059.

CONCLUSION: The reduced mortality risk of CRT-D compared with an ICD alone began early after device implantation and was sustained during long-term follow-up; the reduced risk for ventricular tachyarrhythmias did not emerge until 6 months after device implantation.

CLINICAL TRIAL REGISTRATION: http://clinicaltrials.gov/ct2/show/NCT00947310.

Medical Subject Headings

Age Distribution; Aged; Aged, 80 and over; Cardiac Resynchronization Therapy; Defibrillators, Implantable; Disease-Free Survival; Female; Humans; Male; Middle Aged; Survival Analysis; Tachycardia, Ventricular; Treatment Outcome; United States; Ventricular Fibrillation

PubMed ID

25745075

Volume

17

Issue

7

First Page

1085

Last Page

1091

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