Left Ventricular Diameter and Risk Stratification for Sudden Cardiac Death

Abstract

Background Left ventricular ( LV ) diameter is routinely measured on the echocardiogram but has not been jointly evaluated with the ejection fraction ( EF ) for risk stratification of sudden cardiac death ( SCD ). Methods and Results From a large ongoing community‐based study of SCD (The Oregon Sudden Unexpected Death Study; population ≈1 million), SCD cases were compared with geographic controls. LVEF and LV diameter, measured using the LV internal dimension in diastole (categorized as normal, mild, moderate , or severe dilatation using American Society of Echocardiography definitions) were assessed from echocardiograms prior but unrelated to the SCD event. Cases (n=418; 69.5±13.8 years), compared with controls (n=329; 67.7±11.9 years), more commonly had severe LV dysfunction ( EF ≤35%; 30.5% versus 18.8%; P <0.01) and larger LV diameter (52.2±10.5 mm versus 49.7±7.9 mm; P <0.01). Moderate or severe LV dilatation (16.3% versus 8.2%; P =0.001) and severe LV dilatation (8.1% versus 2.1%; P <0.001) were significantly more frequent in cases. In multivariable analysis, severe LV dilatation was an independent predictor of SCD (odds ratio 2.5 [95% CI 1.03 to 5.9]; P =0.04). In addition, subjects with both EF ≤35% and severe LV dilatation had higher odds for SCD compared with those with low EF only (odds ratio 3.8 [95% CI 1.5 to 10.2] for both versus 1.7 [95% CI 1.2 to 2.5] for low EF only), suggesting that severe LV dilatation additively increased SCD risk. Conclusion LV diameter may contribute to risk stratification for SCD independent of the LVEF . This readily available echocardiographic measure warrants further prospective evaluation.