James Daniels, M.D., is an Associate Professor in the Department of Internal Medicine’s Division of Cardiology at UT Southwestern Medical Center.

A specialist in cardiac arrhythmias, he also leads the UT Southwestern’s Pacemaker and Defibrillator Clinic. He joined the UT Southwestern faculty in 2009.

In addition to his patient care responsibilities, Dr. Daniels frequently lectures UT Southwestern’s cardiology, electrophysiology, and internal medicine trainees. His current research interests include MRI-compatible implantable cardiac devices and atrial fibrillation.

Dr. Daniels earned his medical degree at UT Southwestern. He performed both an internal medicine internship and an internal medicine residency at the University of New Mexico Health Sciences Center. He served an additional year as Chief Medical Resident, during which he was responsible for resident education in addition to attending as a faculty physician on the inpatient wards and outpatient clinic.

He then completed two fellowships at UT Southwestern – one in clinical cardiac electrophysiology, the other in cardiovascular diseases. He also holds bachelor’s degrees in cell biology and chemistry, both with distinction and honors, from the University of Kansas.

Dr. Daniels has published a number of peer-reviewed articles and delivered several invited lectures related to cardiac arrhythmias. He serves as an ad hoc reviewer for publications that include the Journal of Cardiovascular ElectrophysiologyJournal of Investigative Medicine, and American Journal of Cardiology.

American Board of Internal Medicine-certified in internal medicine, cardiovascular disease, and clinical cardiac electrophysiology, Dr. Daniels memberships to professional organizations include the American Heart Association, fellow of the American College of Cardiology (FACC), fellow of the Heart Rhythm Society, and the American Medical Association.

Dr. Daniels was included in D Magazine's Best Doctors list for 2018, 2020, 2021, and 2022.

Personal Note

He and his wife, a dermatologist, have three children.

Meet Dr. Daniels

Arrhythmia Specialist

Everyone’s heart races or feels like it “skips a beat” sometimes. Fortunately, says James Daniels, M.D., what may feel like a cardiac arrhythmia (heart rhythm disorder) may not be. And when it is an arrhythmia, most aren’t dangerous – in the absence of any other heart disease, only a small percentage of arrhythmias are life-threatening.

As a cardiac electrophysiologist at UT Southwestern Medical Center, Dr. Daniels specializes in evaluating and treating arrhythmias, such as atrial fibrillation, in both adults and adolescents.

He is board certified in internal medicine, cardiovascular disease, and clinical cardiac electrophysiology (the subspecialty focused on the heart’s electrical system) and leads UT Southwestern’s pacemaker and defibrillator clinic.

Rhythm disorders related to emotional or physical stress, for instance, typically go away on their own once the stressor is eliminated, says Dr. Daniels, as do those caused by stimulants such as caffeine or those found in some over-the-counter decongestants.

People should seek medical attention if – in addition to feeling like their heartbeat is irregular – they also experience symptoms such as chest painsyncope (fainting), shortness of breath, or feeling faint, he says.

“In the absence of those associated symptoms, people really only need to see a doctor if the feeling of an irregular heart rate occurs frequently enough to be bothersome,” he says. “In most cases, the decision to treat a confirmed arrhythmia – and if so, how – is largely guided by how much a patient is bothered by it.”

Most cardiac arrhythmias can now be successfully treated with medication, or with minimally invasive, catheter-based procedures such as catheter ablation, or with fairly minor surgical procedures, many of which cure certain arrhythmias.

Due to the complex nature of some of the conditions the Heart Rhythm Management team treats, Dr. Daniels and his colleagues work closely with other UT Southwestern medical and surgical clinical teams – including other cardiology subspecialists, cardiac surgeons, and interventional radiologists – to deliver comprehensive care.

“Our collaborative approach to patient management really allows us to take care of the whole person, even with very complicated cases,” he says. “I’m proud that we at UT Southwestern can make a difference in people’s lives and the way they feel.”

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Education & Training
  • Fellowship - UT Southwestern Medical Center (2008-2009), Cardiac Electrophysiology
  • Fellowship - UT Southwestern Medical Center (2005-2008), Cardiovascular Disease
  • Residency - University of New Mexico Health Science Center (2004-2005), Internal Medicine
  • Residency - University of New Mexico Health Science Center (2001-2004), Internal Medicine
  • Medical School - UT Southwestern Medical School (1997-2001)
Professional Associations & Affiliations
  • Heart Rhythm Society
  • American Heart Association
  • American College of Cardiology
Honors & Awards
  • D Magazine Best Doctor, 2018, 2020-2022
  • Certificate of Recognition 2005, University of New Mexico Hospital
Books & Publications
  • Reduction of procedural fluoroscopy (X-ray) exposure
  • Cosmetic pacemaker and defibrillator implantation
  • Aldosterone antagonism to reduce myocardial fibrosis and arrhythmogenesis

Clinical Focus

  • Heart Rhythm Disorders
  • Cardiac Ablation Procedures
  • Genetic Disorders - Familial Arrhythmias
  • Heart Rhythm Treatment/Electrophysiology

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