Heart failure patients with left ventricular ejection fraction (LVEF) between 30 and 35 percent do better with an implantable cardioverter-defibrilators (ICD) than without, a study published June 4 in JAMA confirmed. The findings also support guideline recommendations for use of ICDs in patients with LVEF of less than 30.

Utilizing the National Cardiovascular Data Registries ICD registry, the American Heart Association Get With the Guidelines-Heart Failure database and Medicare files, Sana M. Al-Khatib, MD, MHS, of Duke Clinical Research Institute in Durham, N.C., and colleagues analyzed 3,120 cases with LVEF between 30 and 35 percent and 2,176 cases with LVEF below 30 percent.

According to their results, survival at three years was better with the ICD. Patients with LVEF between 30 and 35 percent with an ICD had a three-year mortality rate of 51.4 percent. A similar cohort who did not have an ICD intervention had a rate of 55 percent. In patients with LVEF with less than 30 percent, the three-year mortality rates were significant: patients with ICDs had a rate of 45 percent as opposed to 57.6 percent for those who didn’t.

Al-Khatib et al stated, “Although the difference in absolute risk by 3 years was not large (3.6 percent at 3 years), it was significant and close in magnitude to what was observed in the clinical trials of prophylactic ICDs (5.3 percent at 3 years in the Sudden Cardiac Death in Heart Failure Trial and 5.6 percent at about 2 years in the Multicenter Automatic Defibrillator Implantation Trial II).”

Previous studies included ICD implantations in patients with LVEF of less than 35 percent but were under powered in the groups of patents with LVEF between 30 and 35 percent. Despite this, guidelines were based largely off of what is implied by those results.

This study, instead, focused predominantly on this population as they are also the largest group being currently given ICDs. “The Centers for Medicare & Medicaid Services have designated patients with an LVEF between 30 percent and 35 percent as an important subgroup for whom more data on ICD effectiveness are needed,” wrote Al-Khatib et al. “Therefore, our findings in the current study fill an important gap in knowledge.”