INFLUENCE OF EXERCISE-INDUCED MYOCARDIAL-ISCHEMIA ON THE PATTERN OF LEFT-VENTRICULAR DIASTOLIC FILLING - A DOPPLER ECHOCARDIOGRAPHIC STUDY

Previous studies using Doppler echocardiography to evaluate left ventricular diastolic filling have shown that myocardial ischemia induced by coronary balloon angioplasty or atrial pacing results in a decrease in the left ventricular inflow peak early (E) to peak atrial (A) velocity ratio. To investigate the effects of exercise-induced ischemia on Doppler-derived filling variables, 20 patients with coronary artery disease and exercise-induced electrocardiographic changes and regional wall motion abnormalities determined by two-dimensional echocardiography were evaluated and compared with 20 patients without evidence of exercise-induced ischemia. Doppler echocardiography was performed at rest and immediately after exercise before the resolution of exercise-induced wall motion abnormalities. Peak E and A velocities increased from rest to postexercise in both the ischemic and nonischemic groups, although the ischemic group demonstrated a greater increase in peak E velocity (from 68 +/- 15 cm/s at rest to 88 +/- 22 cm/s after exercise) than the nonischemic group (70 +/- 13 to 77 +/- 18 cm/s) (p < 0.05 for the difference in response between groups). Accompanying these changes was a slight increase in the peak E/A velocity ratio in the ischemic group (1.04 +/- 0.28 at rest to 1.13 +/- 0.42 after exercise) versus a decrease in the nonischemic group (1.07 +/- 0.30 to 0.90 +/- 0.28) (p < 0.05 intergroup difference). Within the ischemic group, the change from rest to postexercise in peak E/A velocity ratio was related to changes in left ventricular wall motion score (r = 0.61, p = 0.004) and inversely to changes in left ventricular ejection fraction (r = -0.61, p = 0.004) but not to changes in heart rate (r = -0.30, p = NS). This study demonstrates that during exercise-induced ischemia, early diastolic filling is not blunted but is instead maintained. This observation correlates with changes in left ventricular systolic function, suggesting that exercise-induced ischemia may lead to greater increases in left atrial pressure, which augments peak E velocity and results in pseudonormalization of the diastolic Doppler velocity profile.