The Effect of Remote Ischemic Preconditioning on Atrial Fibrillation Recurrence after Successful Electrical Cardioversion - The Prospective Randomised PRECON-AF Trial

Atrial fibrillation (AF) is the most common arrhythmia in Germany and is associated with increased morbidity, mortality and reduced quality of life. Electrical cardioversion (ECV) is a common treatment to restore sinus rhythm (SR) in AF patients. Although ECV has a high initial success rate in restoring SR, it often fails to achieve long-term rhythm control. The potential cardioprotective and antiarrhythmic effects of remote ischaemic preconditioning (RIPC) may improve the overall success rate of ECV, reduce AF recurrence after initial ECV success, and influence cardioversion parameters.

This randomized, prospective, single-blind, single-centre study evaluated the influence of RIPC on early AF recurrence (within 30 days after ECV). The power calculation was based on an assumed 50% reduction in the AF recurrence rate within 30 days, from an initial rate of 30% to 15%. To achieve a statistical power of at least 80% at a significance level of α = 5%, a sample size of 240 patients was required. Patients were randomly assigned in a 1:1 ratio to receive either RIPC or sham preconditioning before ECV. RIPC was induced by three standardized cycles of 5-minute forearm ischemia by inflating a sphygmomanometer to 200 mmHg, followed by 5 minutes of reperfusion. Safety and efficacy data were collected during the intervention and at a separate 30-day follow-up visit. The primary endpoint was AF recurrence within 30 days post-ECV. Safety endpoints included death, stroke, and procedure-related complications. Secondary endpoints were initial success of ECV, mean energy applied, and number of shocks needed to achieve SR.

A total of 240 patients were enrolled and randomized. ECV success rates were similar between the RIPC and sham groups, with success rates of 91% (109/120) in the RIPC group and 88% (105/119) in the sham group (P=0.51). At 30-day follow-up, AF recurrence rates were not significantly different between groups (39% in RIPC vs. 36% in sham; P=0.63). An additional subgroup analysis based on recent (<7 days) versus non-recent (>7 days) AF onset similarly yielded no significant reduction in AF recurrence, with rates of 38% for RIPC vs. 25% for sham (P=0.24) in recent onset AF and 40% (RIPC) vs. 43% sham (P=0.75) in for non-recent AF. There were no significant changes in ECV parameters including mean energy (117 ± 34J RIPC vs. 120 ± 31J sham, P=0.46), number of shocks (1.3 ± 0.6 RIPC vs. 1.4 ± 0.6 sham, P=0.38) and cumulative energy (157 ± 107J RIPC vs. 163 ± 104J, P=0.46 sham) to achieve SR.

Based on this prospectively randomized and adequately powered comparison RIPC has no significant effect on short-term rhythm control or the cardioversion procedure in AF patients.