High incidence of ventricular arrhythmias in patients with left ventricular enlargement and moderate left ventricular dysfunction

BackgroundLeft ventricular ejection fraction (LVEF) 35% is the cutoff value used to identify patients at high risk of sudden cardiac death. However, whether patients who have moderate left ventricular dysfunction and left ventricular enlargement (LVE) have a high risk of ventricular arrhythmias (VAs) and cardiac death is unclear. HypothesisPatients with moderate left ventricular dysfunction and LVE may have a high risk of VAs. MethodsThis study retrospectively analyzed the data of 853 patients who have an implantable cardioverter-defibrillator/cardiac resynchronization therapy cardioverter-defibrillator equipped with home monitoring. The patients were divided into 4 groups: group A, 35% < LVEF 45% and left ventricular end-diastolic dimension (LVEDD) 60mm; group B, LVEF 35% and LVEDD <60mm; group C, 35% < LVEF 45% and LVEDD <60mm; and group D, LVEF 35% and LVEDD 60mm. ResultsDuring a mean follow-up period of 3013months, 324 patients (38%) experienced VAs and 125 patients (14.7%) experienced cardiac death. Based on multivariate Cox regression modeling, group A had an increased risk of VAs (A vs B, hazard ratio [HR]: 1.563, 95% confidence interval [CI]: 1.029-2.375, P = 0.036; A vs C, HR: 1.661, 95% CI: 1.204-2.294, P = 0.002) and cardiac death (A vs B, HR: 1.845, 95% CI: 1.013-3.356; A vs C, HR: 2.041, 95% CI: 1.136-3.731, P = 0.021). Conclusions Patients with moderate left ventricular dysfunction and LVE have a high risk of VAs and cardiac death.