Heart Rhythm Disorders

Clinical Heart and Vascular Center

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Nationally Ranked in Cardiology

UT Southwestern Medical Center is recognized by U.S. News & World Report as one of the nation's top 20 hospitals for cardiology, heart, and vascular surgery.

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About Our Program

At UT Southwestern Medical Center, our arrhythmia center is part of a comprehensive evaluation and treatment program. We have a team of five attending physicians, four advanced practice providers, and more than eight nurses who see outpatients at our modern outpatient center on Inwood Road. Inpatient procedures, including ablations and device implantation, are performed at William P. Clements Jr. University Hospital.

Our state-of-the-art ablation labs feature multiple three-dimensional electroanatomic mapping to provide detailed real-time visualization of arrhythmias during diagnostic and interventional procedures. This allows patients to receive evaluation and treatments with minimal radiation exposure.

At UT Southwestern, our specialists are experts in minimally invasive procedures that treat heart rhythm disorders, including catheter ablation. We use advanced techniques such as pressure-sensitive catheters for heightened precision and cryoablation (freezing of excess heart cells).

Our Heart Rhythm Management team is involved in numerous clinical trials of new treatments and devices, which means our patients have the first available access to novel technologies such as next-generation pacemakers, defibrillators, and ablation tools.

Meet Our Heart Rhythm Specialists

Mark Link, M.D.

A nationally recognized expert in both electrophysiology and hypertrophic cardiomyopathy, Mark Link, M.D., is considered one of the top cardiac specialists in Dallas. As Director of Cardiac Electrophysiology, Dr. Link has been a principal investigator on a number of research studies and a collaborating author of hundreds of articles, abstracts, and chapters in medical journals and textbooks.

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Richard Wu, M.D.

Richard Wu, M.D., specializes in evaluating and treating heart rhythm disorders, and he has special expertise in performing cardiac ablation procedures. After completing advanced training in cardiac electrophysiology at Johns Hopkins, he joined the UT Southwestern faculty in 2006 and has been named a Best Doctor in America every year since 2009, as well as a D Magazine Best Doctor multiple times.

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Jose Joglar, M.D.

Heart rhythm disorder specialist Jose Joglar, M.D., is Director of the Clinical Cardiac Electrophysiology Fellowship Program. A widely published author and editor, he has been recognized multiple times as a D Magazine Best Doctor for Cardiac Electrophysiology.

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James Daniels, M.D.

James Daniels, M.D., is an expert in cardiac arrhythmias and leads UT Southwestern’s Pacemaker and Defibrillator Clinic. He completed advanced training in cardiovascular diseases and clinical cardiac electrophysiology at UT Southwestern, where he has practiced for more than a decade. His current research interests include implantable MRI-compatible cardiac devices and atrial fibrillation.

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Nimesh Patel, M.D.

Nimesh Patel, M.D., specializes in cardiovascular diseases and clinical cardiac electrophysiology. He completed advanced training in those areas at UT Southwestern before joining the faculty in 2020. His clinical interests include ablation for complex arrhythmias, minimizing the use of fluoroscopy, and physiologic pacing. His research interests include atrial arrhythmias in lung transplant recipients.

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What Every Patient Should Know About Heart Rhythm Disorders

The heart’s upper chambers, or atria, serve as receptacles for blood, while the lower chambers, or ventricles, pump blood in and out of the heart. The heartbeat is created by an electrical impulse originating in the right atrium. The electrical activity spreads through the walls of the atria and causes them to contract, forcing blood into the ventricles.

Anomalies in the flow of electricity can cause arrythmias. While some arrythmias are dangerous and can cause sudden cardiac death, others are not life-threatening but may be inconvenient.

An electrophysiologist (EP) is a cardiologist who specializes in the management of the heart’s electrical properties and is the most knowledgeable specialist to deal with the many often complex options for diagnosing and treating heartbeat, or heart rhythm, disorders.

Key Terms

What is an arrythmia? The term "arrhythmia" refers to any change from the normal sequence of the heart’s electrical impulses. This change produces an irregular heartbeat, which is called an arrythmia.

Atrial fibrillation (AFib) is a rapid, irregular heartbeat caused by chaotic electrical impulses in the heart’s atrium. It is estimated to affect as many as one in every 10 people aged 65 and over. Atrial fibrillation may be temporary and even asymptomatic, but it can lead to serious complications such as stroke and heart failure. Treatments include anticoagulation and left atrial occlusion devices to prevent strokes, as well as antiarrhythmic drugs and ablation to prevent atrial fibrillation.

Atrial flutter is similar to AFib but the abnormal heartbeat is more regular and can persist for many days or even weeks. In a small number of cases, atrial flutter results from ablation procedures for atrial fibrillation as the heart develops new electrical pathways to bypass the treated area. While atrial flutter may also lead to serious complications, curing the condition with ablation is possible in most individuals.

Supraventricular (atrial) tachycardia (SVT) includes arrhythmias originating in the upper chambers of the heart. Many involve a circular pathway in the atrioventricular (AV) node. In others, an extra electrical pathway between the atria and the ventricles allows signals to bypass their normal route through the heart, causing abnormally rapid heartbeats. These are generally not life-threatening arrhythmias, but they can be quite irritating. Medical treatment or cardioversion therapy may be required to return the heart to its normal rhythm. Catheter ablation is often very effective in curing SVTs.

In ventricular tachycardia, abnormal electrical signals in the ventricles prevent them from filling and pumping blood efficiently. Without prompt medical treatment, ventricular tachycardia may lead to ventricular fibrillation, a medical emergency that may lead to sudden death because the ventricles quiver chaotically and ineffectively instead of pumping blood.

Implantable defibrillators (ICDs) are often used for patients with ventricular tachycardia. These devices are placed under the skin and continually monitor patients for life-threatening arrhythmias. If a life-threatening arrhythmia is seen the device treats it and stops it.

Bradycardia, or an abnormally slow heartbeat, may be caused by conditions such as sick sinus syndrome, in which the heart’s sinus node does not send electrical impulses through the heart properly. The heart’s electrical pathways may also be blocked by damaged heart muscle, such as after a myocardial infarction.

Sick Sinus Rhythm (SSS) is not a disease but a group of signs or symptoms that show that the heart's natural electrical pacemaker, the sinus node, is not working properly. Treatment usually involves implantation of a pacemaker, along with medication.

Further Reading

Hypertrophic Cardiomyopathy (HCM)

Is an unusual but not uncommon cardiac genetic condition that causes a thickened heart muscle. It is the most common cause of sudden cardiac death in young people and in athletes. People with HCM are also at risk for atrial fibrillation and heart failure.

Arrhythmogenic Right Ventricular Dysplasia (ARVD)

Occurs when the muscle tissue in the right ventricle dies and is replaced with scar tissue.

Conduction Disorders

Affect the way in which electrical impulses travel through the heart

"We take great pride in treating all patients the same, and providing world-class medical treatment here."

James Daniels, M.D.

Risk Factors

Risk factors for cardiac arrhythmias vary, depending on the particular type of rhythm disorder. Some of these, such as family history/genetics and age, are not modifiable. However, beneficial lifestyle changes to address risk factors for overall cardiac disease, such as obesity, sleep apnea, inactivity, diabetes, smoking, excessive alcohol consumption, and hypertension, can reduce the risk for AFib.


Symptoms from arrhythmias are highly variable. They include palpitations, skipping, fluttering, lightheadedness, fatigue, chest pain, and difficulty breathing.

Many people have palpitations that may raise concerns about a possible heart rhythm disorder. Such palpitations may be caused by too much caffeine (including that found in chocolate), alcohol, nicotine, stress, exercise, dehydration, or by an abnormal heart rhythm. Even when palpitations are caused by a heart rhythm disorder, most aren’t dangerous.

However, if a patient has palpitations accompanied by chest pain, lightheadedness or dizziness, shortness of breath, sweating, or fainting, he or she should seek immediate medical attention. To be safe, consult our doctors if experiencing any of these symptoms:

  • A feeling that the heart is skipping a beat
  • A heartbeat that is too fast or “racing”
  • A heartbeat that is too slow
  • An irregular heartbeat
  • Pauses between heartbeats


Cardiologists who specialize in the treatment of heart rhythm disorders, known as electrophysiologists, use many techniques to evaluate the condition and determine the best treatment procedures, devices, or medications. Tests that may be performed to diagnose arrhythmia include:

  • Electrocardiogram: Measures heart rate, heart rhythm, and strength of electrical signals in the heart
  • Event monitoring: Records and transmits heart patterns using a small, pager-sized device that records electrocardiogram patterns when activated by the patient. Patients can wear these for up to 30 days.
  • Holter monitor: An external device worn by the patient that records a 24-to-48 hour continuous ECG of the heart's electrical activity
  • Implantable loop recorder: A small recording device that is inserted under the skin and monitors the heartbeat for up to five years
  • Echocardiogram: Produces a moving picture of the heart, using a device called a transducer that is placed on the chest
  • Electrophysiology study: Insertion of a specially outfitted catheter close to the heart to measure electrical impulses, pinpoint injured heart muscle, and administer electric impulses to evaluate arrhythmias
  • Cardiac stress testing: Evaluates how the heart performs during exertion, such as walking on a treadmill or riding a stationary bike
  • Wearable monitors: Increasingly, consumer products such as the Apple Watch, Alive Cor, and Fitbit can record an ECG. While these are not as accurate as medical-grade monitors, they still can be useful in making a diagnosis.


UT Southwestern’s multidisciplinary approach offers our patients the best opportunity for longer and healthier lives. Patients and their families receive clear, comprehensive information about the risks and benefits of all treatment options. We then create a treatment plan tailored to each patient’s condition, needs, and goals.

If medications cannot be tolerated or do not significantly reduce arrhythmias, patients may be a candidate for one or more minimally invasive heart rhythm management procedures. UT Southwestern cardiology specialists are renowned for their expertise in these procedures, which include:

  • Catheter ablation: Delivery of focused energy to specific areas of the heart to produce a tiny scar that blocks irregular impulses, curing or minimizing abnormal heart rhythms in many patients
  • Electrical cardioversion: Delivery of an electric current to the chest so that the heart’s rhythm is reset to normal
  • Implantable cardioverter defibrillator (ICD): A small electronic device that is implanted under the skin to continually monitor heart rhythm and deliver an electric current that can regulate or reset the heart’s rhythm as needed. At UT Southwestern, both transvenous and subcutaneous ICDs are available.
  • Implantable pacemaker: A small, battery-operated device surgically placed under the skin that can sense heart rhythms and send electrical impulses through the heart to regulate, increase, or decrease the heartbeat as needed
  • Leadless implantable pacemaker: The next generation of pacemaker technology, the leadless pacemaker is placed directly in the heart without any leads. This eliminates wear-and-tear on leads and reduces infection risk.
  • Cardiac resynchronization treatment (CRT): Placing an additional lead on the outside of the left ventricle may improve heart failure symptoms and quality of life for individuals with heart failure, low ejection fractions, and conduction disease.
  • Left atrial occlusion devices: These devices can reduce the risk of stroke for patients with AFib who can’t take anticoagulants.

For some people with atrial fibrillation, a combination of medications or procedures may be needed to prevent rapid or slow heart rates, restore and maintain normal heart rhythm, and prevent strokes.

Aggressive treatment of other health conditions that may contribute to heart arrhythmias or make them more dangerous, such as sleep apnea, diabetes, and hypertension, can also help improve the overall health of people with arrhythmias such as atrial fibrillation.

Both implantable cardioverter defibrillators and pacemakers may get infected. Infected devices generally need removal. Removal of a device is much riskier than implantation. Surgeons and electrophysiologists at UT Southwestern have safely performed thousands of these removal procedures. Learn more about lead extraction.

Support and Ongoing Care

After arrhythmia has been treated with medication, a surgical procedure, or both, follow-up care helps patients adhere to their post-treatment guidelines and ensure that recovery goes smoothly. Nurse practitioners with specialized training in electrophysiology and arrhythmias are available to provide monitoring and support and answer any questions patients may have. Team members work closely with patients to help them learn how to safely continue their fitness programs and make healthful lifestyle changes.

Get Ready for Your Procedure

If you have a heart procedure scheduled at Clements University Hospital, the following video will help answer a few questions prior to your arrival.