Cardiac arrhythmias during exercise-induced myocardial ischaemia in patients with coronary artery disease.

Exercise may induce ventricular arrhythmias (VA) in patients with coronary artery disease. Exercise-induced VA can identify a subset of patients at higher risk of cardiac sudden death. The role of myocardial ischaemia and/or left ventricular disease in the appearance of VA during exercise is not completely understood. The incidence of VA during exercise-induced myocardial ischaemia was investigated in patients with suspected CAD or those undergoing a stress exercise test after a previous myocardial infarction (MI). Patients were divided in four groups. Group A, 836 patients without a previous MI showing exercise-induced myocardial ischaemia associated with ST-segment depression--group B, 72 patients without a previous MI and exercise-induced ST-segment elevation--group C, 50 patients survivors of a recent (1 month) MI and exercise-induced ST-segment depression--group D, 580 patients with an old MI (greater than 3 months) and a positive exercise test associated with ST-segment depression. Exercise-induced VA were found to be significantly more frequent in patients of groups C (40.0%) and B (23.6%) as compared with groups A (5.1%) and D (7.06%) (P less than 0.001). Furthermore VA in groups B and C were more frequently complex (couplets, triplets, ventricular tachycardia and fibrillation). In all groups the appearance of VA during exercise-induced myocardial ischaemia did not appear to be related to exercise duration, maximal heart rate, maximal work capacity, left ventricular end diastolic pressure, ejection fraction or extent of coronary artery lesions.(ABSTRACT TRUNCATED AT 250 WORDS)