Calcium Antagonist Verapamil and Reperfusion Injury of the Heart

Objective: An experimental study to examine the effect of verapamil, given into a coronary artery, on reperfusion injury.Design: The study was randomized but not blinded.Setting: This study was conducted in the animal laboratory of the Department of Anesthesiology and Critical Care in an academic institution.Participants: The study was performed in an anesthetized open-chest pig model.Interventions: Left anterior coronary artery (LAD) occlusion for 15 minutes followed by 90 minutes of reperfusion. Verapamil or saline was given into the LAD artery either at the time the coronary artery was occluded (ie, during acute severe ischemia or during the reperfusion period).Measurements: LAD artery blood flow, regional myocardial function, and metabolism were assessed by the end-systolic pressure length relationship, regional systolic shortening, postsystolic shortening, regional myocardial oxygen consumption, and local cardiac vein lactate.Conclusions: Verapamil given during ischemia resulted in a shorter period of regional myocardial stunning when compared with saline or verapamil during reperfusion. The difference in the verapamil strategies (ie, verapamil administered during ischemia versus verapamil during the reperfusion period) can probably be explained by a difference in the effective dose of the drug present in the heart at the time reperfusion started rather than the period of administration per se.