Heart HealthAfternoon Heart Surgery May Reduce Muscle Injury But Evidence Remains Thin
This Cochrane systematic review examined whether scheduling on-pump cardiac surgery in the afternoon versus the morning improves patient outcomes, based on the idea that circadian rhythms affect how well the heart tolerates surgical stress. After searching major databases through January 2025, researchers found only one eligible randomized controlled trial — an 88-person French study comparing morning versus afternoon aortic valve replacement. The afternoon group showed lower cumulative troponin release over 72 hours, suggesting less heart muscle injury. However, no differences were found in heart attacks, atrial fibrillation, ejection fraction, or hospital stay. No deaths occurred in either group. The overall evidence quality was rated very low, and the authors concluded that much larger, well-designed trials are urgently needed before surgical scheduling changes can be recommended.
