RCT: Patients with atrial fibrillation (AF) who continued their usual caffeinated coffee intake after cardioversion experienced less recurrence of AF or atrial flutter compared to those who abstained from coffee and caffeine.

Main Outcomes and Measures The primary end point was clinically detected recurrence of AF or atrial flutter over 6 months.

Results Two hundred patients (mean [SD] age, 69 [11] years; 71% male) were randomized to caffeinated coffee consumption (n = 100) or coffee abstinence (n = 100). Baseline coffee intake was 7 cups (IQR, 7–18) per week in both groups. During follow-up, coffee intake in the consumption and abstinence groups was 7 (IQR, 6–11) and 0 (IQR, 0–2) cups per week, respectively, resulting in a between-group difference of 7 cups (95% CI, 7–7) per week. In the primary analysis, AF or atrial flutter recurrence was less in the coffee consumption (47%) than the coffee abstinence (64%) group, resulting in a 39% lower hazard of recurrence (hazard ratio, 0.61 [95% CI, 0.42–0.89]; P = .01). A comparable benefit of coffee consumption was observed with AF recurrence only. There was no significant difference in adverse events.

Conclusions and Relevance In this clinical trial of coffee drinkers after successful cardioversion, allocation to consumption of caffeinated coffee averaging 1 cup a day was associated with less recurrence of AF or atrial flutter compared with abstinence from coffee and caffeinated products.