Left Ventricular Ejection Fraction during Exercise in Coronary Arterial Disease

Myocardial ischemia should be associated with an altera- tion of left ventricular performance. A first-transit mdi- onuclide method (collimated scintillation probe; radioac- tivemtechnetium) was used to measure left ventricular ejection fraction at rest and during supine bicycle exer- cise in iS men with coronary arterial disease and in 15 normal men. All normal men had an increased left ventricular ejection fraction during exercise (mean ± SE, 0.66 ± 0.01 to 0.79 ± 0.02; P < 0.001). During exercise in the men with coronary arterial disease, the left ven- tricular ejection fraction decreased (0.49 ± 0.03 to 0.44 ± 0.03; not significant). Sublingual administration of 5 mg of isosorbide dinitmate increased the left ven- tricular ejection fraction both at rest (0.60 ± 0.03; P < 0.001) and during exercise (0.64 ± 0.04; P <0.001) sosorbide dinitrate is a drug which appears to have effects on the cardiovascular system that are qualitatively similar to those of nitroglycerin. Iso- sorbide dinitrate decreases the left ventricular filling pressure, end-diastolic volume, and systemic arterial pressure and increases the left ventricular ejection fraction at rest in patients with coronary arterial disease.'' In addition, this drug has been shown to improve abnormal left ventricular segmental wall motion in patients with coronary arterial disease and myocardial infarction.4 Battock and associates5 ob- served increased performance of treadmill exercise with administration of isosorbide dinitrate in pa- tients with coronary arterial disease. A distinct ad- vantage of isosorbide dinitrate over nitroglycerin is the prolonged duration of action of isosorbide dini- trate following either oral or sublingual administra- tion."4 In several recent studies the left ventricular ejec- tion fraction during exercise either failed to increase normally or actually decreased in patients with coro- nary arterial disease, even in those with a normal ejection fraction at rest.�8 In the present study the in the men with coronary arterial disease. ST-segment depression (more than 1 mm) was observed in aD men during exercise in the control period. With administra- tion of isosorbide dinitrate and exercise to the same work- load, S-T segments were normal in ten of the men with coronary arterial disease. Following administration of isosorbide dinitrate in the men with coronary arterial disease, exercise was associated with a decreased heart rate (107 ± 5 vs 119 ± 5 beats per minute; P <0.01) and decreased systemic arterial blood pressure (148 ± 7 mm Hg/80 ±2 mm Hg vs 167 ± 9 mm Hg/85 ± 2 mm Hg; P < 0.05). The effects of administration of isosorbide dinitrate on left ventricular ejection fraction, heart rate, systemic blood pressure, and ST-segment depression at rest and during exercise were sustained for three hours.