SQ-31765 is a benzazepine calcium channel blocker. SQ-31765 (SQ 31,765) can reduce the severity of ischemia in a manner which is independent of changes in myocardial blood flow or hemodynamic alterations. Anesthetized dogs are given saline (n=6), SQ-31765 (n=6; 0.2 mg/kg) or SQ 32,189 (n=6; 0.2 mg/kg) i.v. 10 min before ischemia. The effect on pacing-induced ST-segment elevation (pacing+left anterior descending coronary artery stenosis) and myocardial blood flow are determined. SQ-31765 reduces ST-elevation (P<0.05) compared to saline at 10, 40 and 70 min after infusion (5.9±1.4 and 12.0±1.4 mV, respectively, at 70 min). Left anterior descending coronary artery stenosis during atrial pacing resulted in a significant reduction in subendocardial flow in all groups before drug infusion (41±7, 44±7 and 35±9 mL/min/100 g for saline, SQ-31765 and SQ 32,189, respectively).