Abstract 3238: Synergy Between Severe LV Systolic Dysfunction and LVH for Risk of Sudden Cardiac Death
Background: The Framingham Heart Study reported an association between increased LV mass/hypertrophy (LVH) and sudden death that was independent of coronary risk factors. Severely decreased LV systolic dysfunction (LVEF ≤ 35%) is an established predictor of SCD risk, but the potential for enhancement of SCD risk in combination with LVH has not been evaluated.
Methods: In an ongoing population-based study, adult residents of a metro area (population 1,000,000) who suffered SCD in association with coronary artery disease (CAD) were identified prospectively (2002–2005). The subgroup of consecutive SCDs that had a cardiac echo performed prior to, and remote from cardiac arrest was identified. Echocardio-graphic findings were evaluated and LV mass normalized for body surface area calculated (American Society of Echocardiography modified equation). Comparisons were conducted with a geographically matched control group of subjects with known CAD, but no history of SCD.
Results: LV mass was available for 99 SCD cases with established CAD (mean age 71, 29% female), as well as 100 controls (mean age 68, 32% female). Patients with severe aortic stenosis or hypertrophic cardiomyopathy were excluded (6 SCDs, 2 controls). LV mass was significantly greater in cases vs controls and this was consistent for unadjusted LV mass (247 vs. 215 g, p=0.02) as well as LV mass adjusted for body surface area (124 g/m2 vs. 108 g/m2, p=0.008). Among SCD cases, 40% had LVH vs. 22% in controls (p=0.01). In a logistic regression model controlling for age, LVH was independently associated with SCD (OR 2.3, 95% CI 1.2 – 4.4, p=0.009). In a logistic regression model including both age and LV dysfunction, there was an interaction between LVH and severe LV dysfunction (p =0.05). In the presence of severe LV dysfunction, LVH increased the odds of SCD by 8-fold (OR 8.1, 95% CI 2.4 –28.2).
Conclusions: LVH and severe LV systolic dysfunction combined appear to substantially increase risk for SCD (8-fold). These findings have implications for refinement of SCD risk stratification.