Archive for the ‘Cardiac Resynchronization Therapy’ Category

Journal Club 2 April 2014


Survival with Cardiac-Resynchronization Therapy in Mild Heart Failure





The Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchro-nization Therapy (MADIT-CRT) showed that early intervention with cardiac-resyn-chronization therapy with a defibrillator (CRT-D) in patients with an electrocardio-graphic pattern showing left bundle-branch block was associated with a significant reduction in heart-failure events over a median follow-up of 2.4 years, as compared with defibrillator therapy alone.


We evaluated the effect of CRT-D on long-term survival in the MADIT-CRT popula-tion. Post-trial follow-up over a median period of 5.6 years was assessed among all 1691 surviving patients (phase 1) and subsequently among 854 patients who were enrolled in post-trial registries (phase 2). All reported analyses were performed on an intention-to-treat basis.


At 7 years of follow-up after initial enrollment, the cumulative rate of death from any cause among patients with left bundle-branch block was 18% among patients ran-domly assigned to CRT-D, as compared with 29% among those randomly assigned to defibrillator therapy alone (adjusted hazard ratio in the CRT-D group, 0.59; 95% confidence interval [CI], 0.43 to 0.80; P<0.001). The long-term survival benefit of CRT-D in patients with left bundle-branch block did not differ significantly according to sex, cause of cardiomyopathy, or QRS duration. In contrast, CRT-D was not associ-ated with any clinical benefit and possibly with harm in patients without left bundle-branch block (adjusted hazard ratio for death from any cause, 1.57; 95% CI, 1.03 to 2.39; P = 0.04; P<0.001 for interaction of treatment with QRS morphologic findings).


Our findings indicate that in patients with mild heart-failure symptoms, left ventricular dysfunction, and left bundle-branch block, early intervention with CRT-D was associated with a significant long-term survival benefit.

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