It has been shown that brief episodes of myocardial ischemia can render the heart more resistant to a prolonged subsequent ischemic episode. This phenomenon, called "preconditioning," has been described in human beings during coronary angioplasty with the use of clinical, electrocardiographic (ECG), or metabolic parameters. The goal of this study was to assess this phenomenon further with the use of echocardiographic and metabolic parameters in addition to clinical and ECG parameters. Eighteen patients with isolated stenosis of the left anterior descending coronary artery and a normal left ventricular function were included. Angioplasty consisted of four consecutive balloon inflations. Sequential changes in clinical, ECG (intracoronary ECG), echocardiographic, and metabolic parameters of myocardial ischemia were compared between the first and the fourth balloon inflations. Improved tolerance to myocardial ischemia with repeated coronary occlusions was demonstrated by a significant reduction in the severity of angina, ST-segment elevation, wall motion abnormalities, and lactate production. This study confirms the adaptation of myocardial ischemia to repeated coronary occlusions through measurement of clinical, ECG, echocardiographic, and metabolic parameters.