Silent Myocardial Ischemia: Safety and Effectiveness of Exercise-Based Cardiac Rehabilitation

BACKGROUND: Silent myocardial ischemia (SMI) predicts adverse outcomes in coronary artery disease, yet the effects of cardiac rehabilitation (CR) in this group are limited. We evaluated the impact of CR on peak exercise capacity, ischemic threshold, training workload progression, medication adherence, depression, and exercise-related adverse events in patients with documented SMI Type I and II. METHODS: This retrospective cohort study includes 966 patients referred to CR. Twenty-nine patients who completed ≥1 session and had valid pre and post exercise tests were included in the final analysis. Main outcomes were changes in peak exercise capacity and ischemic threshold. Rate of adverse events, medication compliance, adverse drug reactions, and cardiac depression scores were also evaluated. Paired t tests were used (α=0.05). RESULTS: Exercise-based CR resulted in a clinically and statistically significant improvement in exercise capacity (MET peak : 8.43 ± 2.51 to 9.14 ± 2.81, P < .001). At ischemic threshold, heart rate increased (123.94 ± 16.08 to 127.82 ± 17.23, P < .001), systolic blood pressure reduced (167.41 ± 33.14 to 164.41 ± 22.59, P = .006), and rate-pressure product increased (21939.53 ± 5362.54 to 22013.88 ± 4203.48, P = .009). The rate of exercise-related adverse events was low (2.23 per 100 sessions), with no major adverse events. Compliance with medications remained above 85% pre-to-post CR, with only 1 reported adverse drug reaction. CONCLUSIONS: Exercise-based CR is safe and effective for patients with SMI, improving exercise capacity and ischemic tolerance with few adverse events. These findings support integrating CR into the management of asymptomatic, high-risk coronary patients.