title: Caffeine and cardiac arrhythmias.
abstract: OBJECTIVE
  To review the evidence supporting the belief that caffeine causes cardiac arrhythmias.
  
  
  METHODS
  Studies published since 1982 identified through computerized searches of MEDLINE, TOXLINE, and Chemical Abstracts and a review of bibliographies of relevant articles on the subject of caffeine and cardiac arrhythmias.
  
  
  METHODS
  All clinical studies examining caffeine as a cause of cardiac arrhythmias and a selection of basic science experiments to illustrate caffeine's effects in vitro.
  
  
  METHODS
  Study quality was assessed and all available clinical data pertaining to caffeine as a cause of arrhythmias were summarized.
  
  
  RESULTS
  In one electrophysiologic study, caffeine was associated with an increased susceptibility to provoked cardiac arrhythmias. In five placebo-controlled trials, caffeine in doses up to 500 mg daily (equivalent to 5 to 6 cups of coffee) did not increase the frequency or severity of ventricular arrhythmias. One large epidemiologic study reported an increase in the frequency of ventricular extrasystoles in persons consuming 9 or more cups of coffee daily.
  
  
  CONCLUSIONS
  Moderate ingestion of caffeine does not increase the frequency or severity of cardiac arrhythmias in normal persons, patients with ischemic heart disease, or those with pre-existing serious ventricular ectopy.
authors.affiliation: Division of Cardiology, Sunnybrook Health Science Centre, Toronto, Ontario.
authors.forename: M G
authors.initials: MG
authors.lastname: Myers
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000139:chemically induced*; D002110:Caffeine / Q000009:adverse effects* / Q000633:toxicity; D004594:Electrophysiology; D006321:Heart / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques
chemical_list: D002110:Caffeine