title: Effect of caffeine on ventricular arrhythmia: a systematic review and meta-analysis of experimental and clinical studies.
abstract: OBJECTIVE
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Post-Graduate Program in Health Science: Cardiology and Cardiovascular Sciences, Porto Alegre, RS, Brazil.
authors.forename: Priccila
authors.initials: P
authors.lastname: Zuchinali
authors.affiliation: Post-Graduate Program in Health Science: Cardiology and Cardiovascular Sciences, Porto Alegre, RS, Brazil.
authors.forename: Paula A B
authors.initials: PA
authors.lastname: Ribeiro
authors.affiliation: Cardiovascular Division of Hospital de Clínicas de Porto Alegre, Ramiro Barcelos 2350, room 2061, Porto Alegre, RS 90035-003, Brazil.
authors.forename: Maurício
authors.initials: M
authors.lastname: Pimentel
authors.affiliation: São Lucas Hospital of the Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, RS, Brazil.
authors.forename: Priscila R
authors.initials: PR
authors.lastname: da Rosa
authors.affiliation: Post-Graduate Program in Health Science: Cardiology and Cardiovascular Sciences, Porto Alegre, RS, Brazil Cardiovascular Division of Hospital de Clínicas de Porto Alegre, Ramiro Barcelos 2350, room 2061, Porto Alegre, RS 90035-003, Brazil Department of Internal Medicine, Medical School, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors.forename: Leandro I
authors.initials: LI
authors.lastname: Zimerman
authors.affiliation: Post-Graduate Program in Health Science: Cardiology and Cardiovascular Sciences, Porto Alegre, RS, Brazil Cardiovascular Division of Hospital de Clínicas de Porto Alegre, Ramiro Barcelos 2350, room 2061, Porto Alegre, RS 90035-003, Brazil Department of Internal Medicine, Medical School, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil rohde.le@gmail.com.
authors.forename: Luis E
authors.initials: LE
authors.lastname: Rohde
mesh_terms: D000818:Animals; D002110:Caffeine / Q000008:administration & dosage / Q000009:adverse effects*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000009:adverse effects*; D006329:Heart Conduction System / Q000187:drug effects* / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D016017:Odds Ratio; D018570:Risk Assessment; D012307:Risk Factors; D018879:Ventricular Premature Complexes / Q000139:chemically induced* / Q000503:physiopathology
chemical_list: D000697:Central Nervous System Stimulants; D002110:Caffeine
keywords: Arrhythmias; Caffeine; Coffee