ICDs may decrease all-cause mortality in patients with nonischemic cardiomyopathy

A meta-analysis of four randomized trials found that using primary prevention implantable cardioverter defibrillators (ICDs) decreased all-cause mortality by 25 percent in patients with nonischemic cardiomyopathy.

Lead researcher Sana M. Al-Khatib, MD, MHS, of Duke University Medical Center, and colleagues published their results online in JAMA Cardiology on March 29.

For this analysis, the researchers searched PubMed as well as bibliographies of pertinent articles and queries of experts. They identified randomized trials that lasted at least 12 months, reported on all-cause mortality and compared ICDs versus medical therapy in at least 100 patients with nonischemic cardiomyopathy. The four studies were published from Jan. 1, 2000, through Oct. 31, 2016.

The four studies were the DEFINITE trial, the Cardiomyopathy Trial (CAT), the SCD-HeFT trial and the DANISH trial.

The researchers examined a total of 1,874 patients, including 937 in the ICD group and 937 in the medical therapy group. When they pooled data with fixed- and random-effects models from the studies, they found there was a statistically significant 25 percent reduction in all-cause mortality.

They also performed two sensitivity analyses, one in which they excluded the CAT trial and one in which they excluded the DANISH trial. The results did not change much in either analysis, according to the researchers. In addition, they conducted a meta-regression accounting for each trial’s year of publication and found that the time of publication did not affect the relationship between the use of an ICD and all-cause mortality.

The researchers mentioned the main limitation of the meta-analysis was that they did not have patient-level data for the CAT and DANISH trials, although the did have patient-level data for the other two studies.

“Based on the totality of evidence, our findings support the 2012 guidelines of the American Heart Association, American College of Cardiology Foundation, and Heart Rhythm Society for ICDs,” the researchers wrote. “The guidelines recommend the use of ICDs in eligible patients with nonischemic cardiomyopathy and a depressed left ventricular ejection fraction.”