Evaluation of left ventricular contractility indexes for the detection of symptomatic and silent myocardial ischemia

Abstract

This study evaluated the role of left ventricular (LV) ejection fraction and systolic blood pressure (BP) to end-systolic volume ratio to detect symptomatic and silent myocardial ischemia. The sensitivity and diagnostic accuracy of these contractility indexes were compared with angina and ST depression during exercise. Thirty consecutive patients referred for chest pain performed symptom-limited bicycle exercise and had coronary angiography within 3 months. Twenty-two had angiographically significant coronary artery disease and 8 had normal coronary anatomy. Systolic BP was measured by sphygmomanometry; LV ejection fraction and end-systolic volume were obtained by nuclear ventriculography. Normal values for contractility indexes were defined as LV ejection fraction >52% at rest and increment of ≥5% during exercise, and systolic BP to end-systolic volume ratio >2.2 mm Hg/ml at rest and >3.0 mm Hg/ml during exercise. The sensitivity of systolic BP to end-systolic volume ratio to identify patients with coronary artery disease at rest was 71 vs 33% for LV ejection fraction. During exercise, each contractility index had a sensitivity of 95% and there was a combined sensitivity of 100%. This compares with 71% for ST depression and 48% for exercise-induced angina. Thus, 52% had no angina and 36% of them were also silent by electrocardiography. Among the patients with symptomatic ischemia, 20% had no ST-segment depression. Measurement of contractility indexes enhanced the detection of silent myocardial ischemia and provided information on LV function vital to prognosis and management of patients with coronary artery disease.