Department Cardiovascular Medicine
Primary Location Cleveland Clinic Main Campus
Type of Doctor Adults Only
Languages English
Surgeon No
Cleveland Clinic Main Campus
Primary Location

Cleveland Clinic Main Campus


Additional Locations

Specialties & Treatments

Treatment & Services

  • Advanced Ischemic Heart Disease Center
  • Atrial Fibrillation Center
  • Biventricular Pacemaker
  • Cardiac Electrophysiology
  • Cardiac Electrophysiology & Pacing Section
  • Cardiovascular Medicine
  • Cardiovascular Medicine Department
  • Cardioversion
  • Catheter Ablation
  • Clinical Trials
  • Implantable Cardioverter Defibrillator
  • Lead Extraction (ICD, Pacemaker)
  • Lifevest
  • Pacemaker Implant
  • Pulmonary Vein Ablation Procedure
View all 15 Treatment & Services +

Specialty in Diseases & Conditions

  • Abnormal Heart Beats - Women
  • Abnormal Heart Rhythms
  • Arrhythmogenic Right Ventricular Dysplasia
  • Atrial Fibrillation
  • Atrial Flutter
  • Bradyarrhythmias
  • Cardiac Implantable Electronic Device Infection
  • Heart Palpitations
  • Long QT Syndrome (LQTS)
  • Sudden Cardiac Death (Sudden Cardiac Arrest)
  • Supraventricular Tachycardia
  • Syncope
  • Ventricular Fibrillation
  • Ventricular Tachycardia
  • Wolff-Parkinson-White Syndrome (WPW)
View all 15 Specialties +


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About Thomas Callahan, MD

Thomas Callahan, IV, MD, is Staff Physician and Director of Inpatient Services in the Section of Pacing and Electrophysiology of the Sydell and Arnold Miller Family Heart, Vascular & Thoracic Institute at Cleveland Clinic. He is also the Associate Program Director for Cleveland Clinic’s cardiology and electrophysiology fellowships.

In addition to office visits, Dr. Callahan also offers scheduled follow up virtual visits to select patients, through the Cleveland Clinic Express Care ® Online app. This platform allows patients to see their physician live, using their smartphone, tablet or computer.

Specialty interests: Abnormal heart rhythm, atrial fibrillation, sudden cardiac death, supraventricular tachycardia, ventricular tachycardia, PVCs, Wolff-Parkinson-White syndrome, biventricular pacemaker, catheter ablation, implantable cardiac defibrillator, lead extraction

Number of Procedures Performed: Dr. Callahan has performed more than 900 catheter ablation procedures throughout his career.

Success rates: Cleveland Clinic has been ranked the #1 hospital for cardiology and heart surgery by U.S. News & World Report since 1994. Success rates for specific procedures are available at

Education and Training: Dr. Callahan received his undergraduate degree from Oberlin College, OH. He received his master's degree from the University of Michigan, and he earned his medical degree from Eastern Virginia Medical School, Norfolk. He joined Cleveland Clinic in 2003 and completed fellowships in Cardiovascular Medicine Cardiac Electrophysiology and Pacing. Prior to coming to Cleveland Clinic, he was a resident at the Hospital of the University of Pennsylvania, where he was Chief Resident in internal medicine.

Publications and Speaking:  Dr. Callahan has authored and co-authored many articles published in leading medical journals.

About Dr. Callahan: “I enjoy my field because we have the ability to make many patients feel dramatically better. I am also excited by the constant advancement in the field.”

Leisure Activities: Dr. Callahan is a private pilot. He also enjoys skiing and spending time with his family.

Education & Professional Highlights

Education & Professional Highlights


Education & Fellowships

Fellowship - Cleveland Clinic
Cardiovascular Medicine
Cleveland, OH USA

Residency - Hospital of the University of Pennsylvania
Internal Medicine
Philadelphia, PA USA

Internship - Hospital of The University of Pennsylvania
Internal Medicine
Philadelphia, PA USA

Medical Education - Eastern Virginia Medical School
Norfolk, VA USA

Graduate School - University of Michigan
Ann Arbor, MI USA

Undergraduate - Oberlin College
Oberlin, OH USA


  • Internal Medicine - Cardiovascular Disease
  • Internal Medicine - Clinical Cardiac Electrophysiology
  • Internal Medicine - Cardiovascular Disease

Specialty Interests

Abnormal heart rhythm, atrial fibrillation, sudden cardiac death, supraventricular tachycardia, ventricular tachycardia, PVCs, Wolff-Parkinson-White syndrome, biventricular pacemaker, catheter ablation, implantable cardiac defibrillator, lead extraction

Awards & Honors

  • 2006, Dawson Award for Clinical Excellence and Humanism
  • 2004, Frederic J. Pashkow Award for Clinical Excellence
Research & Publications

Research & Publications

See publications for Thomas Callahan, MD.

(Disclaimer: This search is powered by PubMed, a service of the U.S. National Library of Medicine. PubMed is a third-party website with no affiliation with Cleveland Clinic.)

Industry Relationships

Industry Relationships

Cleveland Clinic physicians and scientists may collaborate with the pharmaceutical or medical device industries to help develop medical breakthroughs or provide medical expertise or education. Cleveland Clinic strives to make scientific advances that will benefit patient care and support outside relationships that promise public benefit. In order for the discoveries of Cleveland Clinic physicians' and scientists' laboratories and investigations to benefit the public, these discoveries must be commercialized in partnership with industry. As experts in their fields, Cleveland Clinic physicians and scientists are often sought after by industry to consult, provide expertise and education.

To assure professional and commercial integrity in such matters, Cleveland Clinic maintains a program that reviews these collaborations and, when appropriate, puts measures in place to minimize bias that may result from ties to industry. Cleveland Clinic publicly discloses the names of companies when (i) its physicians/scientists receive $5,000 or more per year (or, in rare cases, equity or stock options) for speaking and consulting, (ii) its physicians/scientists serve as a fiduciary, (iii) its physicians/scientists receive or have the right to receive royalties or (iv) its physicians/ scientists hold any equity interest for the physician's/scientist's role as inventor, discoverer, developer, founder or consultant.* In publicly disclosing this information, Cleveland Clinic tries to provide information as accurately as possible about its physicians' and scientists' connections with industry.

As of 7/6/2020, Dr. Callahan has reported no financial relationship with industry that is applicable to this listing. In general, patients should feel free to contact their doctor about any of the relationships and how the relationships are overseen by Cleveland Clinic. To learn more about Cleveland Clinic's policies on collaborations with industry and innovation management, go to our Integrity in Innovation page.

Public Health Service-Reportable Financial Conflicts of Interest. Cleveland Clinic scientists and physicians engage in basic, translational and clinical research activities, working to solve health problems, enhance patient care and improve quality of life for patients. Interactions with industry are essential to bringing the researchers' discoveries to the public, but can present the potential for conflicts of interest related to their research activities. Click here to view a listing of instances where Cleveland Clinic has identified a Public Health Service (PHS)-Reportable Financial Conflict of Interest and has put measures in place to ensure that, to the extent possible, the design, conduct and reporting of the research is free from bias.

* Cleveland Clinic physicians and scientists subscribe to the guidance presented in the PhRMA Code on Interactions with Healthcare Professionals and the AdvaMed Code of Ethics on Interactions with Health Care Professionals. As such, gifts of substantial value are generally prohibited.

Patient Satisfaction Reviews

198 Patient Satisfaction Reviews

The Patient Satisfaction Rating is an average of all responses to the care provider related questions shown below from our nationally-recognized Press Ganey Patient Satisfaction Survey. Patients that are treated in outpatient or hospital environments may receive different surveys, and the volume of responses will vary by question.

Responses are measured on a scale of 1 to 5 with 5 being the best score.

The comments are submitted by patients and reflect their views and opinions. The comments are not endorsed by and do not necessarily reflect the views of Cleveland Clinic.

Overall Star Ratings
4.9 out of 5
Explains 4.9
Listens 5
Courtesy, Respect & Concern 4.9
Patient Rating of Doctor 5

41 Patient Comments

Reviewed on Aug 28, 2020

the doctor was excellent at explaining my options and explaining the procedure in a way I could understand and follow.

Reviewed on Aug 25, 2020

Dr. Callahan is a highly competent cardiologist who has contributed greatly to my good health and well being.

Reviewed on Aug 14, 2020

Dr. Callahan does an above average job of listening to me and answering my questions.

Reviewed on Aug 11, 2020

Dr. Callahan answered almost all my questions before I even asked them. I left the clinic feeling like I am exactly in the right place and with the right doctor to perform my upcoming procedure.

Reviewed on Jul 31, 2020

Dr.Callahan did an excellent job explaining options & procedures and was very personable.

Reviewed on Jul 31, 2020

I was able to schedule an appointment within a week from the time I called. I was amazed by the courtesy of the entire staff from the time we stepped into the facility and since I was from out of state they attempted to schedule every necessary appointment on that date. Dr. Callahan is easy to talk and I trust his judgement in my cardiac care.

Reviewed on Jul 31, 2020

Dr. Callahan is extremely knowledgeable & possesses the ability to share this information clearly & concisely.

Reviewed on Jul 14, 2020

Dr.Callahan was excellent-- listen to my problems, gave alternatives and advice.

Reviewed on Jun 1, 2020

Dr Callahan and staff are outstanding with their communication skills

Reviewed on May 19, 2020

Dr Callahan is the best!

Reviewed on May 19, 2020

All of my questions were answered. Dr. Callahan carefully explained test results. He has an excellent manner with patients. He really cares about people.

Reviewed on May 15, 2020

I respect & trust Dr Callahan

Reviewed on May 15, 2020

I will always refer Cleveland Clinic because of my experience with Dr Callaghan

Reviewed on Mar 6, 2020

Dr Callahan is a very caring professional with great bedside manner

Reviewed on Feb 28, 2020

Dr Callahan is an excellent doctor. He takes his time to listen and answer all questions. I would definitely recommend him.

Reviewed on Feb 21, 2020

Dr.Callahan made me feel at ease about my heart,he listened,assessed,and was very thorough. I also like that he uses updated technology and made it clear he was easy to reach if I have any concerns.

Reviewed on Feb 14, 2020

A very good session with Dr. Callahan. Really helped me understand my options as well as get a valuable second opinion.

Reviewed on Feb 14, 2020

Dr C is excellent.

Reviewed on Jan 31, 2020

Dr. Callahan was very knowledgeable and provided great feedback regarding my symptoms. He is waiting for insurance approval for further testing.

Reviewed on Jan 28, 2020

dr. Callahan! all the people I came into contact were great!

Reviewed on Jan 10, 2020

Dr. Callaghan is wonderful! He took the time to answer all my questions and explained things throughly. I highly recommend him!

Reviewed on Jan 10, 2020

As stated earlier Dr. Callaghan was wonderful

Reviewed on Jan 2, 2020

My pacemaker was set correctly. Dr. Callahan answered all my questions.

Reviewed on Jan 2, 2020

I thought very highly of Dr. Callahan. I would recommend him to anyone that has a heart problem.

Reviewed on Jan 2, 2020

I have been recommending the Dr. & the Clinic in general.

Reviewed on Dec 31, 2019

Dr. Callahan was exceptional. I am now hopeful and less anxious about my condition and treatment options/long term prognosis

Reviewed on Dec 7, 2019

We tell everyone about this incredible hospital, perhaps a little too much. We are so thankful for the brilliant physicians and the kind and attentive care.

Reviewed on Nov 19, 2019

for Callahan has given me peace of mind and options for treatment should it become necessary excellent physician I have already recommended Cleveland clinic to relatives and friends

Reviewed on Nov 19, 2019

Dr. Callahan was excellent. So glad he took care of me.

Reviewed on Nov 18, 2019

Dr Callahan was wonderful to work with. He answered my questions as deep and technical as I wanted to go with honesty and full disclosure.

Reviewed on Nov 15, 2019

Love Dr Callahan!

Reviewed on Oct 22, 2019

Dr Callahan is one of the best listeners I have encountered

Reviewed on Oct 22, 2019

Wonderful Doctor and Staff. They touch my heart.

Reviewed on Oct 18, 2019

Dr. Callahan was absolutely amazing. he listened, took the time and was very kind

Reviewed on Oct 18, 2019

probably the best doctor I ever had I'm covering any question that I had to ask him very relaxed and very nice and very thorough

Reviewed on Oct 14, 2019

Very difficult to get a message to this dr. and get a timely response. Suggestion was for me to use email on mychart but sometimes need to talk to someone by phone.

Reviewed on Oct 11, 2019

Dr Callahan is an amazing doctor- the best! He is so kind and takes time to answer questions. He also is so smart!

Reviewed on Oct 11, 2019

Everyone was kind and concerned. Both my parents now see Dr Callahan because of my experience with him.

Reviewed on Sep 24, 2019

wonderful experience. wish I would have come to CC and Dr Callahan two years ago

Reviewed on Sep 24, 2019

Dr Callahan was extremely personable ama easy to talk to. He listened to all my concerns and did not rush me at all. I feel very comfortable with him as my doctor.

Reviewed on Sep 10, 2019

Dr. Callihan listened to my multiple questions, offered me options and then encouraged me to think about my decision. He walked me out of the office to the scheduler and also retrieved my educational material for me.

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