BETA-BLOCKER INFUSION DID NOT IMPROVE LEFT-VENTRICULAR DIASTOLIC FUNCTION IN MYOCARDIAL-INFARCTION - A DOPPLER-ECHOCARDIOGRAPHY AND CARDIAC-CATHETERIZATION STUDY

Left ventricular (LV) diastolic function changes after myocardial infa rction. It has been suggested that beta blockers may improve diastolic function in hypertensive and heart failure patients. Doppler echocard iographic filling patterns and invasive hemodynamic indices have been used to analyze LV diastolic function. To determine the effect of beta blockers on LV diastolic function, we studied 32 patients with anteri or wall myocardial infarction with a mean age of 53 years. Peak early and late flow velocities, peak early-to-late flow velocities ratio, pr essure half time, diastolic filling period, isovolumic relaxation time , cardiac index, mean arterial pressure, wedge pressure, and systemic and pulmonary vascular resistance indices were obtained simultaneously before and after an intravenous infusion of 10 mg of atenolol. Cardia c index decreased from 4.27 +/- 0.97 to 3.19 +/- 0.91 l/min/m2 (p = 0. 0001); mean arterial pressure decreased from 85 +/- 10 to 80 +/- 11 mm Hg (p = 0.004); wedge pressure increased from 11 +/- 5 to 13 +/- 4 mmH g (p = 0.002); systemic vascular resistance index increased from 1586 +/- 409 to 1980 +/- 634 dyn.m2.s/cm5 (p = 0.0002); pulmonary vascular resistance index increased from 115 +/- 58 to 163 +/- 72 dyn.m2.s/cm5 (p = 0.0004); peak late flow velocity decreased from 64 +/- 15 to 49 /- 14 cm/s (p = 0.0001); early-to-late ratio increased from 0.95 +/- 0 .35 to 1.29 +/- 0.36 (p = 0.0001); diastolic filling period increased from 300 +/- 108 to 400 +/- 110 ms (p = 0.0001) and isovolumic relaxat ion time increased from 133 +/- 29 to 143 +/- 29 ms (p = 0.009). No si gnificant changes were observed for peak early flow velocity and press ure half-time. Multivariate regression analysis suggests that signific ant changes observed on Doppler echocardiographic parameters can be at tributed in part to beta-blocker effect on heart rate analyzed as dias tolic filing period. We concluded that beta blocker infusion changes L V diastolic function analyzed by Doppler echocardiography in patients with anterior wall myocardial infarction. Moreover, the increase obser ved on wedge pressure suggests deterioration in cardiac function.