Thromboxane receptor blockade with SQ 30,741 improves post-ischemic myocardial function in anesthetized dogs.

This study was conducted to determine whether the thromboxane A2 receptor antagonist SQ 30,741 can improve post-ischemic recovery of cardiac function in anesthetized dogs. Saline or SQ 30,741 was infused throughout a 15-min coronary occlusion and 5 hr of reperfusion. Ischemic regional cardiac function was determined using subendocardial ultrasonic crystals. Despite no differences in collateral blood flow or reperfusion flow, SQ 30,741 significantly improved ventricular segmental shortening at all times measured during reperfusion. At 5 hr after the initiation of reperfusion, segmental shortening was 3 +/- 16 and 44 +/- 10% of baseline values for saline and SQ 30,741 groups, respectively. These results implicate thromboxane receptor activation in the pathogenesis of myocardial stunning, and thromboxane antagonists may be useful in mitigating this functional deficit.