for people ages 21 years and up (full criteria)
at San Francisco, California
study started
completion around
Principal Investigator
by Greg Marcus, MDChris Wong, MD
Headshot of Greg Marcus
Greg Marcus



Given both the increasing population impact of atrial fibrillation (AF) and the widespread consumption of coffee in society, determining an associated benefit or risk of coffee consumption on AF is of great clinical relevance. This pilot study will evaluate the effect of randomly assigning participants undergoing electrical cardioversion to coffee abstinence or coffee consumption over a 6 month period. This pilot study will provide the first, randomized evaluation of coffee on AF outcomes and will provide important information on whether or not coffee has any effect on AF recurrence.

Official Title

A Pilot Randomized Controlled Trial to Assess Abstinence of Coffee Compared to Continued Consumption on Recurrent Atrial Fibrillation Following Electrical Cardioversion


The purpose of this study is to assess how abstinence of coffee compared to continued consumption affects recurrent atrial fibrillation (AF) following electrical cardioversion. As one of the most consumed beverages in the world, whether coffee has any effect on health outcomes is of considerable interest to physicians, scientists, and individual consumers. While significant data exist on the potential impact of coffee on many cardiometabolic parameters, there is conflicting data on any role of coffee on AF.

Most studies so far have been observational in nature, limiting how much insight there is on the role of coffee on AF. This study proposes to directly compare AF outcomes for patients with AF that abstain from coffee versus those that continue coffee consumption.

A total of 200 AF patients undergoing electrical cardioversion will be enrolled in this study (100 per arm), and followed for up to 6 months post cardioversion. Differences in AF recurrence, symptoms, and development/recurrence of other arrhythmias will be compared between the two groups.


Atrial Fibrillation, Coffee, afib, Consume coffee, Avoid coffee, Avoid, Consume


You can join if…

Open to people ages 21 years and up

  • Men and women ≥ 21 years of age
  • Sustained AF
  • Planned/scheduled direct current electrical cardioversion
  • Consumption greater than or equal to one cup of coffee per day sometime in the past 5 years
  • Willing and able to comply with coffee abstinence or continuation
  • Life expectancy of at least 1 year
  • Willing and able to return and comply with scheduled phone follow up visits
  • Willing and able to provide written informed consent

You CAN'T join if...

  • Established allergy or adverse reaction to coffee
  • Stated inability to comply with coffee abstinence or continuation
  • AF ablation in preceding 6 months or planned in next 6 months
  • Recent cardiothoracic surgery in preceding 3 months
  • Cardioversion for atrial flutter rather than AF
  • Pregnancy or desire to get pregnant within next 6 months.
  • Current enrollment in an investigation or study of a cardiovascular device or investigational drug that would interfere with this study
  • Any other criteria, which would make the patient unsuitable to participate in this study as determined by the Principal Investigator (e.g., an uncontrolled drug and/or alcohol addiction)


  • UCSF Parnassus accepting new patients
    San Francisco California 94143 United States

Lead Scientists at UCSF

  • Greg Marcus, MD
    Dr. Gregory Marcus is a specialist in the treatment of arrhythmias, including mapping and catheter ablation for atrial fibrillation, supraventricular tachycardias and ventricular arrhythmias. He is also an expert in pacemaker, biventricular device and defibrillator implantation. RESEARCH Dr. Marcus is Associate Chief of Cardiology for Research at UCSF Health. He is also an Ass…
  • Chris Wong, MD


accepting new patients
Start Date
Completion Date
University of California, San Francisco
Study Type
Expecting 200 study participants
Last Updated