Atrial pacing in coronary artery disease, including preinfarction angina and postoperative studies

Abstract

Right atrial pacing studies were performed in 58 patients with coronary artery disease and in 15 normal subjects. Angina pectoris was induced in 58 percent of patients with coronary artery disease at an average heart rate of 129 ± 3 beats/min; ischemic S-T segment depression was noted in 63 percent of such patients experiencing angina pectoris and in 31 percent of those without angina. The greater the severity of coronary artery disease, the more frequent the pacing-induced angina. The main hemodynamic difference between the normal subject and the patient with coronary artery disease was the failure of the left ventricular end-diastolic pressure to decrease during pacing in the latter. Pacing ventricular function curves were abnormal in 60 percent of patients with coronary artery disease in the absence of angina pectoris and abnormal in 90 percent during induced chest pain. Pacing studies were safely performed in 8 patients with unstable angina pectoris, with angina induced by pacing in 7. No significant hemodynamic differences were noted between these patients and those with stable coronary artery disease. Significant postoperative hemodynamic abnormalities were noted in 9 patients; preoperative and postoperative studies indicated little improvement in myocardial performance after aortocoronary arteryvein bypass surgery.