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Gregory M. Marcus
4.9 out of 5 (113)
Gregory M. Marcus

Gregory M. Marcus, MD

Electrophysiology | Cardiology

Cardiac Electrophysiology and Arrhythmia Service
400 Parnassus Ave., Fifth Floor,
San Francisco, CA 94143
+1 more location
(415) 353-2873
4.9 out of 5 (113)
Virtual visits available
4.9 out of 5 (113)
Virtual visits available
Cardiac Electrophysiology and Arrhythmia Service
400 Parnassus Ave., Fifth Floor,
San Francisco, CA 94143
+1 more location
(415) 353-2873

Dr. Gregory Marcus is a cardiologist and electrophysiologist who specializes in the diagnosis and treatment of arrhythmias, including cardiac mapping and catheter ablation for atrial fibrillation, supraventricular tachycardias and ventricular arrhythmias. He is also an expert in implanting pacemakers, biventricular devices and defibrillators.

In his research, Marcus studies heart rhythm disturbances, and the health effects of common lifestyle factors such as alcohol, caffeine, smoking and other substances, and leads several large projects to use sensors, smart phones and other technologies to conduct clinical research.

Marcus earned his medical degree from George Washington University School of Medicine & Health Sciences. He completed his residency at Stanford Medicine. He then completed his training in cardiovascular medicine and cardiovascular electrophysiology at UCSF.

  • Board Certifications

    American Board of IM/Clinical Cardiac Electrophys, Clinical Cardiac Electrophysiology

  • Fellowships

    UCSF Graduate Medical Education, Cardiac Electrophysiology

    UCSF Graduate Medical Education, Cardiovascular Disease

  • Residencies

    Stanford University Medical Center-GME, Internal Medicine

  • Degree

    MD, George Washington University School of Medicine

Conditions I specialize in

Treatments I provide

Where I see patients (2)

    My reviews

    4.9

    Overall Experience
    113 Ratings
    About our process
    Oct 20, 2025
    Dr Marcus is very friendly, attentive, knowledgeable, and willing to help. He listened carefully and answered my questions thoroughly. He is considerate, encouraging and provided options for the management and helped me to choose at my comfort level. Previously he answered my questions promptly on MyChart. He is wonderful!
    Jul 12, 2025
    Very good and helpful experience
    Mar 19, 2025
    Very satisfied with the care and the service
    Feb 04, 2025
    Dr. Marcus (as always) provided a high-level of professional medical advice which made a difference to me in that it was the basis on which I changed my thinking and resulted in a direction in change of care on my part. The conversation was much appreciated.
    Dec 07, 2024
    I asked the doctor whether it would be safe to stop taking a blood thinner (Eliquis). He discussed the pros and cons and offered to consult with his colleagues as it was a judgment call. He got back to me (through My Chart) that same day with a recommendation. Amazing!
    Nov 02, 2024
    Dr Marcus was so present, answering all my questions with no rush. I felt I was in excellent hands & well cared for.
    Sep 19, 2024
    Care provider knowledgeable and reassuring
    Jul 27, 2024
    Good explanation: Tight and to the point, says this old editor. The whole group did excellently.
    Jul 22, 2024
    The conversation with my doctor addressed all questions about my condition. He did not have access to one the results at the appt but followed up the same day once they had been uploaded to MyChart. I appreciated having the one year follow up appt in person
    Jul 07, 2024
    I am so thankful for the care I received from everyone at UCSF
    May 13, 2024
    Very professional but also somewhat transactional without much empathy. Just stating the facts without much consideration for me as a person.
    May 06, 2024
    Listened answered all my questionsExcellent
    Mar 30, 2024
    Gregory made me part of the decision making with my care

    Selected research

    See all research
    Decorative Caduceus

    Digitally Rendered Interventions And Knowledge To Limit Ethanol-Associated Atrial Fibrillation ...

    The primary outcome will be change in atrial fibrillation severity at one year, defined by a change in the Atrial Fibrillation Effect on Quality-of-Life Questionnaire (AFEQT) score from baseline to one year associated with alcohol...

    Recruiting

    Decorative Caduceus

    Full-Avoidance vs. Permissive/Regulated Drinking & Outcomes On Fibrillation

    Participants will be wearing a continuously recording ECG monitor for two weeks. The primary outcome will be the presence (versus absence) of at least one AFib episode on randomly assigned drinking versus non-drinking days.

    Recruiting

    Decorative Caduceus

    Gauging Outcomes of Total Milk Ingestion on Lipid and gControl

    The primary outcome will be a difference in hemoglobin A1c (HbA1c) with whole-fat milk compared to skim milk during the enrollment period.

    Recruiting

    Decorative Caduceus

    Volunteers to Investigate Best Results for Ablation and Novel Therapies for Atrial Fibrillation

    Time to atrial fibrillation, after employing a 3-month blanking period. Atrial Fibrillation Recurrence includes patient-reported symptoms of AF or Kardia-based ECG evidence of AF.

    Recruiting

    Decorative Caduceus

    Disrupted Sleep and Concurrent Ectopy or Atrial Fibrillation

    Daily number of ectopic beats as recorded with the adhesive heart monitor

    Recruiting

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