Abstract 11960: Right Ventricular Diameter in Risk Stratification of Sudden Cardiac Death

Abstract

Introduction: Right ventricular (RV) abnormalities have been linked with the risk of sudden cardiac death (SCD) in general population. This study was designed to evaluate the additional value of right ventricular diameter (RVD) in predicting life-threatening ventricular tachycardia (VT)/ventricular fibrillation (VF) in patients with implantable cardioverter-defibrillators (ICD). Hypothesis: We hypothesized that higher value of RVD would be an easily accessible predictor in decision-making of ICD implantation. Methods and Results: We enrolled 954 chronic heart failure patients, with quantitative measurements of echocardiograms obtained before ICD implantation, and then divided them according to the median level of RVD. Fine-Gray subdistribution and Cox proportional hazard regression analyses were performed to estimate the predictive value of RVD in sustained VT/VF vs. non-arrhythmic mortality (defined as death without prior sustained VT/VF), respectively. Patients with higher median level of RVD had a significantly higher incidence of VT/VF (32.9% versus 26.7%; P=0.041) over the median follow-up of 2.83 years (interquartile range: 1.33-5.27 years). After adjustment for multiple clinically relevant variables, high RVD levels were significantly associated with an increased risk of VT/VF (per 1 SD increase, hazard ratio=1.16; 95% CI, 1.05-1.27; P=0.003), but not non-arrhythmic mortality (per 1 SD increase, hazard ratio=0.97; 95% CI, 0.82-1.14; P=0.680). When adding RVD to the Seattle Proportional Risk Model (SPRM) and the MADIT-ICD VT/VF risk score, the combined models yielded significant improvement in discrimination for VT/VF. Elevated RVD also contributed to residual risk beyond left ventricular parameters including left ventricular end-diastolic diameter (LVEDD) and left ventricular ejection fraction (LVEF). The restricted mean survival time measure indicated that life gained with ICD implantation in RVD higher group were 11.0, 28.4 and 29.1 days more than their lower counterparts in one, two, and three years’ time. Conclusions: RVD is associated with a significantly increased risk of sustained VT/VF in chronic heart failure patients, and provides greater prognostic power when combined with current risk assessment tools.