Key result
LVEF ≤20% linked to ~23% higher VT/VF risk and increased mortality versus LVEF >20%.
Why the study?
Patients with heart failure and low LVEF face competing risks of death from VT/VF, pump failure, or non-cardiac causes, prompting assessment of LVEF and VT/VF risk considering non-arrhythmic mortality as a competing factor.
Does very low LVEF (≤20%) increase the risk of ventricular tachyarrhythmias and appropriate ICD shocks compared to higher LVEF (>20%) in primary prevention ICD recipients, accounting for competing mortality?
Does very low LVEF (≤20%) increase the risk of ventricular tachyarrhythmias and appropriate ICD shocks compared to higher LVEF (>20%) in primary prevention ICD recipients, accounting for competing mortality?
In primary prevention ICD recipients, very low LVEF (≤20%) is associated with a significantly higher risk of VT/VF and appropriate ICD shocks compared to LVEF >20%, even after accounting for the competing risk of non-arrhythmic mortality.
LVEF ≤20% was associated with higher VT/VF and shock rates in primary-prevention ICD recipients; extends prior associations but leaves optimal thresholds for risk stratification open.
Background Patients with heart failure and low left ventricular ejection fraction (LVEF) are at higher risk of death from ventricular tachycardia or ventricular fibrillation (VT/VF), pump failure, or non-cardiac causes. This study aimed to assess the association between LVEF and VT/VF risk, considering non-arrhythmic mortality as a competing factor. Methods The study comprised 5,168 primary prevention implantable cardioverter defibrillator (ICD) recipients from five major trials (MADIT-II, MADIT-CRT, MADIT-RIT, MADIT-RISK, RAID), categorized by LVEF tertiles (EF ≤20%, EF 21-29%, EF 30-35%). Outcomes included VT/VF, VT over 200 BPM or VF, appropriate ICD shocks, and mortality, with Fine and Gray regression models used to adjust for death as a competing risk in arrhythmia outcomes. Results At 3 years of follow-up, the cumulative incidence of VT/VF was 28% in patients with LVEF ≤20% (n=1504), 23% in those with LVEF 21–29% (n=2011), and 20% in the LVEF 30-35% (n=1653) group (Gray’s test, p<0.001, Figure). Multivariate analysis revealed that compared to patients with EF >20%, patients with EF ≤20% had significant 23% increased risk of VT/VF (p=0.004), 33% increased risk of fast VT/VF (p=0.001), and 31% increased risk of appropriate ICD shocks (p=0.003), even after accounting for competing risks of death. This increased VT/VF risk in lower EF patients was consistent across different subgroups, including age, sex, presence of CRT-D, and non-ischemic cardiomyopathy. Additionally, patients with EF ≤20% had a 1.5-fold higher risk of all-cause mortality compared to those with EF >20% (p<0.001). Conclusions Patients with very low LVEF show a markedly increased risk of VT/VF and ICD shocks, even when considering the competing risk of non-arrhythmic mortality, confirming the potential benefit of ICD therapy in this high-risk population.
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Barsheshet et al. (2025) studied this question. Patients with LVEF ≤20% had 23% higher VT/VF risk, 33% higher fast VT/VF risk, 31% higher ICD shock risk, and 1.5-fold increased mortality versus EF >20% at 3 years.
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