Nicorandil, a potent cardioprotective agent, reduces QT dispersion during coronary angioplasty

BACKGROUND: Previous studies have found that ST-segment elevation and QT dispersion are smaller in second coronary occlusions than in first occlusions, a trend that suggests ischemic preconditioning. It has not been established whether nicorandil reduces ST-segment elevation and QT dispersion during coronary angioplasty. METHODS AND RESULTS: Thirty patients with stable angina undergoing coronary angioplasty in the proximal left anterior descending artery were randomly assigned to one of two groups, receiving either 5 mg oral nicorandil 3 times daily (n = 15) or placebo (n = 15). In the control patients, the total ST-segment elevation decreased from 14 +/- 3 mm during the first inflation to 7 +/- 2 mm during the second inflation (P < .01). In contrast, in the nicorandil-treated patients, the total ST-segment elevation during the second inflation was roughly equivalent to that during the first inflation (8 +/- 3 mm vs 8 +/- 3 mm, P = not significant). After the first reperfusion, a significantly smaller increase in QT dispersion was observed in the nicorandil-treated patients than in the control patients (43 +/- 15 ms vs 54 +/- 15 ms, P < .001). However, after the second reperfusion, QT dispersion was similar for the two groups (32 +/- 15 ms vs 34 +/- 13 ms, P = not significant). CONCLUSIONS: Nicorandil may precondition the myocardium and may prevent the occurrence of ventricular arrhythmias after coronary reperfusion by suppressing the increase in QT dispersion.