Effect of caffeine on ventricular arrhythmia: a systematic review and meta-analysis of experimental and clinical studies

The relationship between caffeine consumption and the occurrence of arrhythmias remains controversial. Despite this lack of scientific evidence, counselling to reduce caffeine consumption is still widely advised in clinical practice. We conducted a systematical review and meta-analysis of interventional studies of the caffeine effects on ventricular arrhythmias. The search was performed on Pubmed, Embase, and Cochrane database, and terms related to coffee, caffeine, and cardiac arrhythmias were used. Methodological quality was assessed based on The Cochrane Collaboration recommendations and the ARRIVE guidelines. There were 2016 citations retrieved on the initial research. After full-text assessment, seven human and two animal studies were included in the meta-analysis. In animal studies, the main outcome reported was the ventricular fibrillation threshold. We observed a significant mean difference of -2.15 mA (95% CI -3.43 to -0.87; I-2 0.0%, P for heterogeneity = 0.37). The main outcome evaluated in human studies was the rate of ventricular premature beats (VPBs). The overall relative risk for occurrence of VPBs in 24 h attributed to caffeine exposure was 1.00 (95% CI 0.94-1.06; I-2 13.5%, P for heterogeneity = 0.32). Sensitivity analysis for caffeine dose, different designs, and subject profile was performed and no major differences were observed. Our meta-analysis demonstrates that data from human interventional studies do not show a significant effect of caffeine consumption on the occurrence of VBPs. The effects observed in animal studies are most probably the result of very high caffeine doses that are not regularly consumed in a daily basis by humans.