Protective effects of pretreatment with intracoronary nifedipine on myocardial ischemia and dysfunction.

To assess whether pretreatment with intracoronary nifedipine protects the myocardium against acute ischemia induced by coronary occlusion, 18 patients were studied during coronary angioplasty of the left anterior coronary artery. After a control occlusion of 60 seconds, 0.1 mg nifedipine was injected and occlusion was repeated for 60 seconds. Before and during the occlusion period, pulmonary capillary pressure was measured and the intracoronary epicardial ECG was recorded. After intracoronary administration of nifedipine, the onset of the rise in diastolic filling pressure was delayed from 23 to 38 seconds (p less than 0.01) and the changes at 60 seconds of occlusion were reduced from 14 to 11 mmHg (p less than 0.05). Nifedipine delayed the appearance of ischemic ST-segment elevation in the intracoronary ECG from 11 to 21 seconds (p less than 0.01) and diminished the changes at 60 seconds of occlusion from 1.8 to 1.2 mV (p less than 0.05). These findings suggest that pretreatment with intracoronary nifedipine protects the myocardium against some of the mechanical and electrocardiographic consequences of regional ischemia during acute coronary occlusion.