Authors: Al-Khatib SM et al., JAMA 2014 Jun 4; 311:2209
In a cross-registry cohort of patients with LVEFs between 30% and 35%, mortality was significantly lower in those who received a device than in those who did not.
Randomized controlled trials (RCTs) of implantable cardioverter-defibrillators (ICDs) in patients with cardiomyopathies have generally restricted enrollment to those with left ventricular ejection fractions (LVEFs) of less than 35%. Yet the median LVEF in these trials is typically well below 30%. Do patients with LVEFs between 30% and 35% derive as much benefit from ICDs as those with lower LVEFs?
In a retrospective cohort study, 408 patients enrolled in the National Cardiovascular Data Registry ICD Registry with LVEFs of 30% to 35% were matched with the same number of patients enrolled in the American Heart Association’s Get With The Guidelines–Heart Failure registry who had similar LVEFs but did not undergo ICD implantation. Adjusted 1-year mortality was 22.8% in ICD recipients, compared with 30.0 in nonrecipients, a significant difference. This mortality benefit persisted at 3 years (47.1% vs. 58.0%; P=0.04).
This retrospective analysis suggests that ICD implantation does confer a significant mortality benefit in patients with LVEFs between 30% and 35%. Although clearly not as compelling as data from an RCT, these data may be all we possess for years to come. The findings are reassuring in that they support current guidelines for ICD implantation, but they also show that mortality for these patients in real-world practice remains quite high. We should employ every means at our disposal to reduce it.