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Effect of coronary arterial bypass surgery on exercise-induced ventricular arrhythmias. Long-term follow-up of a
Insights
Coronary bypass surgery improves exercise performance but does not reduce ventricular arrhythmias in stable angina patients. Ventricular arrhythmias, except tachycardia and fibrillation, are poor predictors of sudden death.
Area of Science:
- Cardiology
- Cardiac Surgery
- Electrophysiology
Background:
- Stable angina pectoris patients often experience exercise-induced ventricular arrhythmias.
- The impact of coronary arterial bypass surgery on these arrhythmias and their link to sudden death requires clarification.
Purpose of the Study:
- To assess the effect of coronary arterial bypass surgery versus medical therapy on exercise-induced ventricular arrhythmias.
- To determine the relationship between ventricular arrhythmias and sudden death in patients with stable angina pectoris.
Main Methods:
- 102 patients with stable angina pectoris were randomized to medical or surgical therapy.
- Symptom-limited treadmill tests were conducted at baseline, 1 year, and 5 years.
- Exercise-induced and resting ventricular arrhythmias were evaluated, alongside exercise performance and sudden death events.
Main Results:
- The surgical group showed improved exercise performance and reduced ischemia at 1 and 5 years compared to the medical group.
- Neither surgical nor medical therapy altered the frequency or severity of exercise-induced or resting ventricular arrhythmias.
- Ventricular arrhythmias, excluding ventricular tachycardia and fibrillation, did not predict sudden death.
Conclusions:
- Coronary bypass grafting does not decrease ventricular arrhythmias in stable angina patients.
- Exercise-induced ventricular arrhythmias, except for ventricular tachycardia and fibrillation, are not reliable predictors of sudden death in this population.
- The study suggests other factors, possibly catecholamine release, may contribute to exercise-induced arrhythmias rather than ischemia.
Abstract:
The effect of coronary arterial bypass surgery on exercise-induced ventricular arrhythmias and their relation to sudden death was examined in 102 patients with stable angina pectoris randomly assigned to medical and surgical therapy (54 and 48 patients, respectively). Symptom-limited treadmill tests were performed at entry and at 1 and 5 years. The surgical group demonstrated significant improvement in exercise performance at 1 year compared with the medical group, and at 5 years exercise-induced ischemia as evidenced by S-T depression and exertional angina remained substantially decreased in the surgical group with little change in the medical group. However, the frequency and severity of exercise-induced ventricular arrhythmias in each group remained unchanged at 1 and 5 years from those at entry. Similar results were obtained from an evaluation of ventricular arrhythmias in the electrocardiogram at rest. With the exception of exercise-induced ventricular tachycardia and fibrillation, no relation was found between ventricular arrhythmias and sudden death. Coronary bypass grafting does not decrease the frequency or severity of exercise-induced or resting ventricular arrhythmias. In patients with stable angina pectoris, with the exception of ventricular tachycardia and fibrillation, exercise-induced ventricular arrhythmias are poor predictors of sudden death. The data suggest that exercise-induced ventricular arrhythmias may not be related to ischemia but to other effects of exercise such as cardiac stimulation by catecholamines or other factors.