Acute myocardial ischemia is known to cause impairment of both left ventricular systolic and diastolic function. To further investigate these changes as well as their relation to common clinical variables (electrocardiographic [ECG] changes and chest pain), 32 patients were evaluated with Doppler echocardiography during coronary angioplasty. Doppler indexes of left ventricular diastolic function included the ratios of peak early to late and peak early to mean diastolic velocities as well as the ratios of early to late and first third to total velocity integral (one-third filling fraction). All diastolic indexes showed significant impairment by 15 seconds after coronary occlusion (ratio peak early to late filling velocity: 1.11 versus 0.96, p less than 0.01; ratio peak early to mean filling velocity: 1.9 versus 1.7, p less than 0.01; ratio early to late velocity integral: 1.58 versus 1.25, p less than 0.01; one-third filling fraction: 41.2 versus 37.7, p less than 0.01). Left ventricular systolic function was evaluated during coronary occlusion both qualitatively, as assessed by the appearance of a new wall motion abnormality on two-dimensional echocardiography (mean 28.8 seconds), and quantitatively by measurement of systolic percent area change on the two-dimensional short-axis view as well as the Doppler echocardiographic stroke integral index. Systolic indexes did not show significant change until 30 seconds after balloon inflation (percent area change: 42.8 versus 29.2, p less than 0.01; stroke integral index: 11.04 versus 9.36, p less than 0.01). ECGs were performed at 15 second intervals.(ABSTRACT TRUNCATED AT 250 WORDS)