Risk of Appropriate Implantable Cardioverter-Defibrillator Therapies and
Sudden Cardiac Death in Patients With Heart Failure With Improved Left
Ventricular Ejection Fraction
Abstract
Background The benefit of implantable cardioverter
defibrillator (ICD) therapy in patients who have heart failure with
improved left ventricular ejection fraction (LVEF) to >35%
after implantation (HFimpEF) is controversial. Methods
Databases (Ovid MEDLINE, EMBASE, Web of Science, and Google Scholar)
were queried for studies of ICD patients that reported the association
between HFimpEF and arrhythmic events (AEs), defined as the combined
incidence of ventricular arrhythmias, appropriate ICD intervention and
sudden cardiac death (primary composite endpoint). Results A
total of 41 studies and 38,572 patients (11,135 with HFimpEF, 27,437
with persistent EF <35%) were included; mean follow up was 43
months. HFimpEF was associated with decreased AEs (OR 0.39, 95% CI
0.32-0.47; annual rate (AR) 4.1% vs. 8%; P<0.01).
Super-responders (EF >50%) had a lower risk of AEs than
patients with more modest reverse remodeling (EF>35% and
<50%, OR 0.25, 95% CI 0.14-0.46; AR 2.7% vs. 6.2%;
P<0.01). HFimpEF patients who had an initial primary
prevention indication had a lower risk of AEs (OR 0.43, 95% CI
0.3-0.61; AR 5.1% vs. 10.3%; P<0.01). Among primary
prevention patients who had never received appropriate ICD therapy at
the time of generator change, HFimpEF was associated with decreased
subsequent AEs (OR 0.26, 95% CI 0.12-0.59; AR 1.6% vs. 4.8%;
P<0.01). Conclusion HFimpEF is associated with
reduced, but not eliminated, risk for AEs in patients with ICDs. The
decision for replacing an ICD in lower risk subgroups should incorporate
shared decision making based on risks for subsequent AEs and procedural
complications.