Clinical Focus: Cardiovascular Medicine: Atrial Fibrillation; Chronic CAD; ACS;

Research Focus:

My primary research interest is the design and conduct of multicenter clinical trials and analyses of important clinical cardiac issues using large patient databases. My research focuses on novel anticoagulation agents for the treatment of acute coronary syndromes and atrial fibrillation, the study of agents targeted to protect the myocardium during reperfusion therapy for acute myocardial infarction, and the evaluation of cardiovascular safety of diabetic therapies. I am also interested in the methodology of clinical trials. Current research activities include standardization of the definition of myocardial infarction used in clinical trials, the adjudication of suspected clinical endpoint events by Clinical Event Committees (CEC), and the efficient operational conduct of large multinational clinical trials.

Administrative Focus: Associate Dean, Clinical Research School of Medicine; Vice Chair of Clinical Research Department of Medicine; Director Stanford Center for Clinical Research; Member of the Stanford IRB

Professional Training:

1985 Stanford University, BS Chemistry
1989 University of Washington, MD
1993 University of Arizona, Internship/Residency/Chief Residency
1996 Duke University, Fellowship in Cardiology
1996 Duke University, Faculty in Cardiology
2013 Stanford University, Faculty Cardiovascular Medicine

Professional Summary

Education & Certifications
  • Fellowship: Duke University (1996) NC
  • Residency: University of Arizona Internal Medicine Residency (1993) AZ
  • Medical Education: University of Washington Medical Center (1989) WA
  • Board Certification: American Board of Internal Medicine, Cardiovascular Disease (1997)

  • Editorial Board Member, Current Cardiology Reviews (2004 - Present)
  • Associate Editor, American Heart Journal (2005 - Present)
  • Editorial Board Member, Current Cardiology Reports (2012 - Present)
  • Editorial Board Member, Cardiology & Therapy Journal (2012 - Present)

Administrative Appointments
  • Member, Stanford Diabetes Research Center (2017 - Present)
  • Steering Committee Member, Department of Medicine Team Science Initiative, Department of Medicine (2022 - Present)
  • Vice Chair of Clinical Research, Department of Medicine (2013 - Present)


Clinical Trials

Clinical trials are research studies that evaluate a new medical approach, device, drug, or other treatment. As a Stanford Health Care patient, you may have access to the latest, advanced clinical trials.

Open trials refer to studies currently accepting participants. Closed trials are not currently enrolling, but may open in the future.

Specializing In

Practice Locations

General Cardiology in Portola Valley Portola Valley, CA
Portola Valley, CA

3260 Alpine Road

Portola Valley , CA 94028

(650) 725-5909

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Patient Ratings

(13 Ratings)

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Patient Reviews

(19 reviews)

He is Always Excellent
An excellent Doctor!...
Dr Mahaffey was not available. Believe I should have been notified of such before I kept the apt.
Dr. Mahaffey was excellent to listen to me and let me know what I need to do to improve my health. Prior to talk to him, I was check my pulse by the nurse and Dr. Nguyen. They just wanted to make sure they did not skip anything at all.
He’s very thorough and friendly.
Very nice, professional, and easy to talk too.
He is a competent and friendly doctor. Easy to talk with, and easy to understand when he explains test results with you.
He is an experienced professional with expertise in his area.
Also excellent! I had no previously seen a cardiologist, but if I were to need one again, I would return.
When asked if I had done research on issues I said I did. I told him what I had learned & he went on to as if he didn't even hear what I had to say.
Dr. Mahaffey and the fellow doctor were very attentive, caring and understanding.
Both doctors listened well & explained thoroughly, helped put my experience of a heart irregularity in perspective.
I LIKED Dr. Mahaffey - warm, friendly, clear, no problems at all.
Very good.
Excellent courtesy & respect in every aspect of my care! Thank you!
Dr. Mahaffey was great.
Dr. Mahaffey & fellow were very thorough in their findings, I feel very confident with their service.

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