Changes in LVEF and Outcomes in ICD and CRT-D Patients

Study Questions:

How does implantable cardioverter-defibrillator (ICD) implantation affect left ventricular ejection fraction (LVEF), mortality, and ICD shocks?

Methods:

PROSE-ICD (Prospective Observational Study of Implantable Cardioverter Defibrillators) was a multicenter study of patients with systolic heart failure eligible for primary prevention ICDs, conducted from 2003 to 2014. The primary endpoint was appropriate ICD shock (defined as shock for ventricular tachyarrhythmias). The secondary endpoint was all-cause mortality.

Results:

The average age of study patients was 58.9 ± 12.2 years. The mean duration between the first measured LVEF and last was 4.9 years; 13% of patients had a lower LVEF at follow-up, 47% had an unchanged LVEF, and 40% had an improved LVEF. Patients with worsened LVEF were more likely to have a higher baseline LVEF, ischemic cardiomyopathy, and diabetes compared to others with unchanged or improved LVEF. Patients with an improved LVEF were more likely to have a cardiac resynchronization therapy-defibrillator (CRT-D) device. A multivariate Cox model comparing patients with an improved LVEF to those with an unchanged LVEF showed hazard ratios were 0.33 (95% confidence interval [CI], 0.18-0.59) for mortality and 0.29 (95% CI, 0.11-0.78) for appropriate shocks.

Conclusions:

Changes in LVEF during follow-up were inversely related to all-cause mortality and appropriate ICD shock with an improved LVEF associated with reduced risk of death and appropriate shocks. Risk of appropriate shock was decreased, but still present in 25% of patients with improved LVEFs.

Perspective:

Although arrhythmic burden still persists despite improvement in LVEF, appropriate ICD therapy can improve LVEF and affect long-term outcomes.

Keywords: Arrhythmias, Cardiac, Cardiac Resynchronization Therapy, Cardiac Resynchronization Therapy Devices, Cardiomyopathies, Defibrillators, Implantable, Heart Failure, Heart Failure, Systolic, Primary Prevention, Risk, Risk Reduction Behavior, Shock, Cardiogenic, Stroke Volume, Tachycardia, Ventricular Function, Left


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