CLINICAL AND DETAILED ANGIOGRAPHIC FINDINGS IN PATIENTS WITH AMBULATORY ELECTROCARDIOGRAPHIC ISCHEMIA WITHOUT CRITICAL CORONARY NARROWING -RESULTS FROM THE ASYMPTOMATIC CARDIAC ISCHEMIA PILOT (ACIP) STUDY

Background: Patients with ambulatory electrocardiographic (AECG) ST-se gment depression and critical coronary narrowing are known to be at in creased risk for adverse outcome, but little is known about patients w ith AECG ST-segment depression without critical coronary narrowing, Hy pothesis: The objectives of this study were to characterize the corona ry angiographic pathology in patients with AECG ST-segment depression but without critical (< 50% diameter stenosis) coronary narrowing and to compare demographic and clinical findings in these patients with th ose enrolled in the Asymptomatic Cardiac Ischemia Pilot Study with AEC G ST-segment depression and critical (greater than or equal to 50% dia meter stenosis) coronary narrowing. Methods: Coronary angiograms from patients with AECG ST-segment depression were reviewed in a central la boratory and quantitative measurement of percent stenosis was performe d. Clinical and angiographic comparisons were made between patients wi th and without critical coronary narrowing. Results: Patients without critical coronary narrowing (n = 64) were younger (p = 0.02), less lik ely to be male (p < 0.001) or to have risk factors for coronary athero sclerosis or a history of myocardial infarction (p < 0.001), and had f ewer ischemic episodes per 24 h on the screening AECG (p = 0.02) than patients with critical coronary narrowing (n = 441). Of patients witho ut critical narrowing, one half had angiographic evidence for coronary artery disease (greater than or equal to 20% stenosis) and 60% had an ejection fraction > 70%. Conclusions: Patients with AECG ST-segment d epression without critical coronary narrowing are heterogeneous, with half having measurable coronary artery disease. Demographically and cl inically, they appear to be different than patients with AECG ST-segme nt depression with critical coronary narrowing.