ATTENUATION OF MYOCARDIAL-ISCHEMIA DURING CORONARY-OCCLUSION BY ULTRASHORT-ACTING BETA-ADRENERGIC-BLOCKADE

To assess the effect of the ultrashort-acting beta blocker esmolol on ischemia induced by acute coronary occlusion, we studied 16 patients undergoing coronary angioplasty. Doppler echocardiography and ECG monitoring were performed continuously before, during, and after balloon occlusion in the drug-free state and during esmolol infusion. Fourteen of the 16 patients had ST segment elevation during balloon inflation. However, maximal ST segment elevation (2.1 +/- 1.5 mm vs 1.7 +/- 1.3 mm, p < 0.001) and duration of ST segment elevation (68 +/- 20 seconds vs 54 +/- 19 seconds, p < 0.05) were both significantly reduced during esmolol infusion. Furthermore, the decrease in ejection fraction seen during drug-free balloon occlusions was significantly blunted during esmolol infusion. In the baseline state ejection fraction decreased from 55% to 38% (p < 0.05) during coronary occlusion compared with a decrease from 52% to 49% (p = NS) during esmolol infusion. In addition, esmolol appeared to delay the onset of segmental wall motion abnormalities after coronary occlusion, occurring at a mean of 40 seconds after balloon inflation versus a mean of 31 seconds in the absence of beta blockade (p < 0.05). Thus the use of ultrashort-acting beta blockade appears to diminish the extent and delay the onset of myocardial ischemia during acute coronary occlusion.