The relative contributions of left ventricular structural changes, dysfunction, and subendocardial ischemia in determining electrocardiographic repolarization abnormalities were assessed in 53 patients with chronic, pure aortic regurgitation and no evidence of coronary artery disease. Thirty-six patients with an abnormal electrocardiographic pattern of repolarization showed larger end-diastolic (154 +/- 46 vs 120 +/- 32 mL/m2; P < .001) and end-systolic (80 +/- 40 vs 52 +/- 30 mL/m2; P = .016) volumes, higher end-diastolic pressure (22 +/- 11 vs 15 +/- 10 mmHg; P = .021), lower ejection fraction (52 +/- 12 vs 59 +/- 13%; P < .05) and greater mass (168 +/- 48 vs 140 +/- 44 g/m2; P < .05) of the left ventricle compared to 17 patients with normal repolarization. Furthermore, patients with repolarization abnormalities also showed higher peak meridian (217 +/- 68 vs 153 +/- 92 Kdyne/cm2; P < .001) and circumferential (358 +/- 110 vs 259 +/- 153 Kdyne/cm2; P < .001) stress and a more spherical shape (end-diastolic shape: 1.4 +/- 0.1 vs 1.5 +/- 0.2, P = .046; end-systolic shape: 1.7 +/- 0.3 vs 1.9 +/- 0.3, P = .026) of the left ventricle. Patients with secondary repolarization abnormalities were also older than patients with normal repolarization (56 +/- 10 vs 40 +/- 11 years; P < .001). However, the diastolic pressure-time index/systolic pressure-time index, which is an estimate of the myocardial oxygen supply-to-demand ratio, was similar in both groups of patients (0.74 +/- 0.3 vs 0.8 +/- 0.2; P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)