alert icon Important Updates

Coming to a Cleveland Clinic location?
Hillcrest Cancer Center check-in changes
Cole Eye entrance closing
Visitation and COVID-19 information

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 and 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 +


Is Cleveland Clinic Part of Your Insurance?

Review a list of accepted insurance plans for our Northeast Ohio locations or learn more about purchasing a contracted managed care plan.

View All Plans

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 is nationally and internationally renowned for the world’s best cardiovascular care. 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 7/3/2023, Dr. Callahan has reported the financial relationships with the companies listed below. 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.

Consulting and/or Speaking. Dr. Callahan receives fees of $5,000 or more per year (or, in rare cases, equity or stock options) as a paid consultant, speaker or as a member of an advisory committee for the following companies:

  • Philips

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

255 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 4.9
Courtesy, Respect & Concern 4.9
Patient Rating of Doctor 4.9

57 Patient Comments

Reviewed on Aug 21, 2023

I had a very positive experience with Dr. Callahan. Clinic staff were all very helpful.

Reviewed on Aug 14, 2023

Dr. Callahan was exceptional in his concern, his explanation of options, and his responses to the many questions.

Reviewed on Aug 14, 2023

Dr Callahan is magnificent. Outstanding in every way

Reviewed on Aug 14, 2023

Dr Callahan was brilliant, kind, caring and took time to explain everything. I like that he stated that at any time I had questions or concerns to reach out to him. I miss Dr Tchou but I really like Dr Callahan's manner, knowledge and concern

Reviewed on Aug 9, 2023

Dr. Callahan was great.

Reviewed on Aug 8, 2023

Dr. Callahan is professional, listened to and answered all my questions thoroughly.

Reviewed on Aug 2, 2023

So glad that I got to see Dr. Callahan. He is not only a great surgeon, but a great man.

Reviewed on Aug 2, 2023

This was my very first meeting with Dr. Callahan. I have been in long term AFib, and I wanted to discuss treatment options with him. He went through each of my options, and completely explained why each WAS NOT my best course of action at this time. His degree of knowledge is very impressive, and he inspired a lot of confidence in me. It was a great first visit!

Reviewed on Jul 31, 2023

Dr Callahan is the best: kind, concerned, smart, and always takes as much time as you need!!

Reviewed on Jul 31, 2023

Dr. Callahan and his staff have taken care of me for a long time. He is very kind, and very talented. Much appreciated.

Reviewed on Jul 17, 2023

As with all good physicians, at every facility, you must take what's offered. Availability is not plentiful.

Reviewed on Jul 10, 2023

I am very pleased to be invited into the medical care of Dr. Callahan. I look forward to receiving his care and guidance.

Reviewed on Jul 10, 2023

Like all situations like this, the doctor only has a short amount of time to address each patient. I wish they were allocated enough time to really focus on my case for 15-20 minutes. Again, this is normal procedure, it would just be great to be the 'only patient' for long enough for the doctor to truly review the file. I really liked Dr. Callahan. He's clearly a true professional.

Reviewed on Jul 10, 2023

Dr. Callahan was patient, professional and more than willing to answer our questions and concerns.

Reviewed on Jul 10, 2023

I found Dr. Callahan to be a professional, knowledgeable, helpful, attentive, and patient EP.

Reviewed on Jul 10, 2023

Dr Callahan is fantastic and has my complete confidence

Reviewed on Jul 10, 2023

Great Experience. I felt that Dr. Callahan listened and heard my concerns. We had a clear plan of action leaving his office.

Reviewed on Jun 27, 2023

Dr Callahan very good doctor

Reviewed on Jun 26, 2023

Dr. Callahan is awesome!

Reviewed on Jun 26, 2023

Provider was amazing with great bedside manner

Reviewed on Jun 17, 2023

*Dr. Wazni is the best doctor I've ever had. Beyond compare -

Reviewed on May 30, 2023

Dr. Extremely knowledgeable & sensitive to all health concerns!-one of the very best doctors I've ever had!!!!

Reviewed on May 30, 2023

In past yr have had & presentlyhave 3rd electrophysiologist (Dr Callahan- the very BEST!

Reviewed on May 30, 2023

From the J2-2 receptionist all the way to Dr. Callahan himself, I was treated with the utmost respect and care. Cleveland Clinic has the "cream of the crop"!

Reviewed on May 30, 2023

Dr. Callahan and his assistant were both excellent and very helpful with my symptoms. I was very Impressed with the Cleveland Clinic downtown and the care and kindness practiced by everyone, from the valets to the physicians and staff.

Reviewed on May 24, 2023

Dr. Callahan is an excellent Doctor who has my best interests covered.... Thank you

Reviewed on May 12, 2023

Dr. Callahan is PHENOMENAL!!!!!

Reviewed on May 12, 2023

The dr gave us a lot of excellent information and I am feeling better. Dr Callahan is not just a 5, he is a 10!

Reviewed on Apr 28, 2023

I am very impressed with the support staff at your facilities. I was also impressed and thankful for the knowledge, consideration, patience and understanding of Dr. Callahan. Look forward to more interactions.

Reviewed on Apr 18, 2023

Dr Callahan is a great doctor but some of that staff on that day were not very caring.

Reviewed on Apr 14, 2023

Dr Thomas Callahan, & staff are AWESOME! They take time to explain everything. They are caring and ask questions to make sure you understand everything!

Reviewed on Mar 31, 2023

Dr. Callahan came highly recommended to me and I was not disappointed. He made a plan to do all my testing and explained all possible outcomes based on those tests. I felt comfortable and confident with him and his team.

Reviewed on Mar 31, 2023

Dr. Callahan's knowledge and understanding of medical issues outside his EP specialty increased my confidence in him tremendously. So many specialists on main campus focus inflexibly within their discipline. Patients are more complicated than that. Dr. Callahan seems to understand that better than many of his colleagues.

Reviewed on Mar 31, 2023

Visit with the Dr. Callahan was fine. He explained to me what I was concerned about and answered my questions. Again, I did not feel rushed after the long wait.

Reviewed on Mar 31, 2023

Physician assistant was easy to deal with. He made us feel relaxed and he answered all of our questions. Very courteous.

Reviewed on Mar 15, 2023

At the time I felt he was just telling me that I was going to need another ablation and dismissing the success of the medications which made me very sad and discouraged. I now realize he is probably correct, but at the time a short Zoom with that kind of news left me rather stunned and discouraged.

Reviewed on Mar 7, 2023

Dr Callahan is a good and respectful listener.

Reviewed on Feb 3, 2023

He was very approachable and was well abreast of my medical history especially since I was his new patient (2 visits only).. He listened to my concerns and answered my questions. He also spent time with me during my visit when many doctors barely give you 20 minutes of their time. I think that I will really like being his patient.

Reviewed on Feb 3, 2023

Doctor and his staff were top rate

Reviewed on Jan 13, 2023

Excellent medical staff. I'm very happy with doctor

Reviewed on Dec 30, 2022

Dr. Callahan was excellent. He took significant time to listen to the details of the episode and history. He spent a significant amount of time explaining the condition, likelihood of recurrence, risk stratification scoring system that contributed to decision making, and the various approaches available. We went over home monitoring devices. He included my input in decisions regarding approach to care. He made sure that my understanding was good and that all of my questions were answered, and he provided educational literature to take home as well as his phone number as needed for future questions and concerns. It was a wonderful example of patient engagement and personalized care.

Reviewed on Dec 27, 2022

Excellent service from Cleve Clinic and Dr. Callahan .

Reviewed on Dec 27, 2022

Dr callahan is the best

Reviewed on Dec 23, 2022

Dr.researched my problem and reassured me of his thoroughness. A very valuable asset to the Cleveland Clinic staff.

Reviewed on Dec 21, 2022

This experience with this provider was great-in general, contacting a provider is usually very difficult unless you have his direct number

Reviewed on Dec 21, 2022

Provider offered a thorough discussion of my problem and options to solve the issue - answered all questions in detail and made an effort to schedule an immediate procedure

Reviewed on Dec 9, 2022

The doctor took a long time to describe my condition in plain language and what treatment options were available.

Reviewed on Nov 29, 2022

Dr Callahan and is entire staff was very knowledgeable, informative and helpful in my family's meeting with them.

Reviewed on Nov 25, 2022

Dr. Callahan is terrific!

Reviewed on Nov 25, 2022

I was very pleased with Dr Callahan I believe he will help I was a surgical nurse for years and just can tell

Reviewed on Nov 18, 2022

Very organized and prompt service. Dr. Callahan explained everything and was very professional! Loved his socks!

Reviewed on Nov 15, 2022

My meeting experience with Dr.Callahan was fantastic. The interview went smoothly Dr. Callahan made my wife and I feel very comfortable and relaxed. We never felt rushed and had an excellent conversation about my issues. Dr.Callahan explained everything to us and answered all our questions in great detail in a way that we could understand. Could not ask for a better session. Some of the news was not that great but he did put us at ease with his delivery and explanation in detail.

Reviewed on Oct 28, 2022

Wonderful dr and place to go too

Reviewed on Oct 28, 2022

Love dr Callahan

Reviewed on Sep 30, 2022

I appreciated meeting with a knowledgeable doctor who was extremely focused on the question of the appropriate procedure for my medical problem

Reviewed on Sep 14, 2022

Dr Callahan and his Staff are truly excellent

Reviewed on Sep 9, 2022

Dr was very professional and very knowledgeable

Back to Top