Changes in Follow-Up Left Ventricular Ejection Fraction Associated With Outcomes in Primary Prevention Implantable Cardioverter-Defibrillator and Cardiac Resynchronization Therapy Device Recipients

Abstract

BACKGROUND Heart failure patients with primary prevention implantable cardioverter-defibrillators (ICD) may experience an improvement in left ventricular ejection fraction (LVEF) over time. However, it is unclear how LVEF improvement affects subsequent risk for mortality and sudden cardiac death (SCD). OBJECTIVES We sought to assess changes in LVEF after ICD implantation and the implication of these changes on subsequent mortality and ICD shocks. METHODS We conducted a prospective cohort study of 538 patients with repeated LVEF assessments after ICD implantation for primary prevention of SCD. The primary endpoint was appropriate ICD shock, defined as a shock for ventricular tachyarrhythmias. The secondary endpoint was all-cause mortality. RESULTS Over a mean follow-up of 4.9 years, LVEF decreased in 13.0%, improved in 40.0%, and was unchanged in 47.0% of the patients. In the multivariate Cox models comparing patients with an improved LVEF to those with an unchanged LVEF, the hazard ratios were 0.33 (95% confidence interval [CI]: 0.18 to 0.59) for mortality and 0.29 (95% CI: 0.11 to 0.78) for appropriate shock, respectively. During follow-up, 25% of patients showed an improvement in LVEF to >35% and their risk of appropriate shock decreased but was not eliminated. CONCLUSION Among primary prevention ICD patients, 40.0% had an improved LVEF during follow-up and 25% had LVEF improved to >35%. Changes in LVEF were inversely associated with all-cause mortality and appropriate shock for ventricular tachyarrhythmia. In patients whose follow-up LVEF improved to >35%, the risk of an appropriate shock remained but was markedly decreased.

Associations between scar characteristics by cardiac magnetic resonance and changes in left ventricular ejection fraction in primary prevention defibrillator recipients

“…Cumulative evidence suggests that improved LVEF is associated with a decreased risk of mortality and appropriate ICD shock for ventricular tachyarrhythmia, particularly in those whose follow-up LVEF improved to >35%. 2–6 Consistent with previous findings, our study reported a trend toward an inverse association between LVEF changes and the risk of appropriate shock. These findings underscore that even partial functional improvement in LVEF may reduce subsequent arrhythmic risk while the majority of appropriate ICD firings occur in those in whom LVEF is static or declining despite aggressive HF therapy.…”

“…20–24 Among primary prevention ICD patients, 25%–40% improve their LVEF after ICD implantation. 2–6 Despite the high prevalence of LVEF improvement, little is known regarding the determinants of LVEF changes among primary prevention ICD recipients. In a case-control study of 102 dilated cardiomyopathy patients, shorter QRS duration, female sex, non-ischemic etiology, absence of diabetes, and higher blood pressure were associated with improved LVEF to normal or near-normal with medical therapy.…”

“…Recent evidence suggests that improved LVEF is associated with a decrease in all-cause mortality and appropriate ICD shock for ventricular tachyarrhythmia,. 2–6 …”

Outcomes After Implantable Cardioverter-Defibrillator Generator Replacement for Primary Prevention of Sudden Cardiac Death

“…Similar to findings in this study, Zhang et al have reported improvement in EF to >35% in 25% of primary prevention ICD recipients with a reduced incidence of ICD therapies in patients with EF improvement. 21 Kini et al 22 also reported a lower incidence of ICD therapy after ICD replacement in patients with improvement in EF to >40% (2.8% versus 10.7% per person-year). In contrast to these observations, LVEF improvement during follow-up was not predictive of reduced appropriate ICD therapy in primary prevention recipients in the Defibrillators in Non-Ischemic Cardiomyopathy Treatment Evaluation trial (DEFINITE) and in a cohort of ICD replacement patients.…”

Ejection Fraction Improvement After Primary Prevention Defibrillator Implantation

“…In this issue of the Journal, Zhang et al(16) step into this maelstrom to offer an important contribution to arrhythmic risk assessment in the HF population. The authors evaluated the association between changes in LVEF after primary prevention ICD and biventricular-pacemaker ICD on ICD shocks and mortality.…”