Differentiation of Ischemic and Dilated Cardiomyopathy on Electrocardiograms

Abstract

Differentiating coronary artery disease with left ventricular dysfunction from dilated cardiomyopathy is important prognostically and therapeutically. To provide a diagnostic algorithm to distinguish these conditions using a standard 12-lead electrocardiogram, all 105 patients with left ventricular ejection fraction < 50% who underwent angiography between January 2004 and December 2006 were studied prospectively. Coronary artery disease was defined as ≥ 50% stenosis of the left main coronary artery or ≥ 70% stenosis of 1 or more of the 3 major epicardial arteries. Normal coronary angiography findings with left ventricular ejection fraction < 50% was defined as dilated cardiomyopathy. The most specific finding for differentiation of these diseases was pathologic Q waves in lead II, aVF, V3 or V4. The most sensitive parameter was a ratio ≥ 5 of R-wave amplitudes in lead V6 and lead III (94% sensitive). The 12-lead electrocardiogram provides a useful noninvasive method for differentiation of dilated cardiomyopathy from coronary artery disease with left ventricular systolic dysfunction.