MADIT-CRT: CRT-D linked to long-term survival benefit in patients with LBBB

Issue: May 2014

WASHINGTON — Seven-year follow-up data of patients from the MADIT-CRT study show a long-term survival benefit for patients with mild HF who receive a cardiac resynchronization therapy defibrillator early.

The study of patients with mild HF symptoms and left ventricular dysfunction (n=1,820) had previously produced favorable short-term morbidity outcomes, driven by a reduction in HF, for those with left bundle-branch block (LBBB) receiving a cardiac resynchronization therapy defibrillator (CRT-D) early (HR=0.66). Seven-year survival outcomes for MADIT-CRT were presented at the American College of Cardiology Scientific Sessions.

Ilan Goldenberg, MD, and colleagues hypothesized that the reduction in HF in the short-term study would correspond with a reduction in mortality over time.

Ilan Goldenberg

They found that at 7 years, those with LBBB in the CRT-D group had a cumulative probability of all-cause mortality of 18% compared with 29% of those with LBBB who received an implantable cardioverter defibrillator only (adjusted HR=0.59; 95% CI, 0.43-0.8).

“The mortality benefit appeared after 1 year of follow-up and continued out to 7 years; this corresponded to nine patients needed to treat with [CRT-D] to save one life during this time period,” Goldenberg, of Sheba Medical Center and Tel Aviv University, Israel, said at a press conference. “We also saw that treatment with [CRT-D] was associated with more than 60% reduction in the risk for a first HF event over 7 years of follow-up.”

The researchers found that the survival benefit in CRT-D patients did not vary by sex, disease etiology or QRS duration.

In patients without LBBB, there was no benefit and possibly harm associated with CRT-D (all-cause mortality adjusted HR=1.57; 95% CI, 1.03-2.39; P for interaction of treatment with QRS morphology<.001), according to the researchers.

“Currently, there is no evidence for any clinical benefit associated with [CRT-D] therapy in those without LBBB,” Goldenberg said.

Enrollment criteria were LV ejection fraction ≤30%, QRS ≥130 ms and NYHA Class I or II. The final follow-up visits for the long-term survival outcome were conducted in September 2013. – by Erik Swain

For more information:

Goldenberg I. Late-Breaking Clinical Trials III. Presented at: American College of Cardiology Scientific Sessions ; March 29-31, 2014; Washington, D.C.

Goldenberg I. New Engl J Med. 2014;doi:10.1056/NEJMoa1401426.

Disclosure: The study was supported by an unrestricted research grant from Boston Scientific. Goldenberg reports no relevant financial disclosures.