Remote Ischemic Preconditioning on New Onset Post-Cardiac Surgery Atrial Fibrillation: A Single-Centre Prospective Clinical Study

Abstract

Background: Remote ischemic preconditioning (RIPC) has been shown to reduce myocardial ischemiareperfusion injury. However, its efficacy in preventing postoperative atrial fibrillation (POAF) remains unsettled. Methods: A total of 97 eligible patients were prospectively randomized to receive either RIPC or shamRIPC (control) prior to coronary artery bypass graft (CABG) surgery. RIPC was performed by applying 3 alternating cycles of a 5-min upper limb ischemia and reperfusion using a blood-pressure cuff. The primary endpoint was the incidence of POAF. Secondary endpoints included cardiac troponin T (cTnT) and H2O2 serum concentration after revascularization, and P-wave duration (PWD) on a 12-lead electrocardiogram. Results: Twelve out of 49 RIPC patients (24.5%) and 18/48 of control patients (37.5%) developed POAF (p=0.165, χ2-test). H2O2 levels were significantly increased 30 min after revascularization in both groups compared to pre-clamping values (8.8±6 vs 25.5±2 and 8.5±5 vs 39±15.5 µM/L in the RIPC and control group, respectively; P<.001, within-group analysis). However, mean differences of H2O2 levels after reperfusion were lower in RIPC patients than in controls (P<.05). cTnT concentrations though increased between 6 and 12 h after operation in both groups, they began to fall later only in the RIPC group. PWD became shorter in RIPC treated patients but not in controls when measured postoperatively (82±13 vs 75±11 ms, P<.01). Conclusion: RIPC did not significantly reduce the incidence of POAF despite decreases in cTnT/H2O2 levels and PWD, indicating that not the extent of myocardial injury but the injury itself triggers the electrophysiologic mechanisms underlying the development of this arrhythmia.