South Denver Cardiology is home to six expert award-winning Electrophysiologists (EP’s) who specialize in the detection and treatment of abnormal heart rhythms. Our EP team treats conditions like atrial fibrillation, supraventricular tachycardia (SVT), bradycardia, palpitations, premature ventricular contractions (PVC’s), and other ventricular rhythm abnormalities to mention a few. Our center provides a specialized program for treating Ventricular Tachycardia with catheter ablation. The EP physicians are developing cutting-edge treatments.  Because of their dedication to innovation, The EP physicians at SDCA regularly publish papers in scientific journals and are invited to present their work at international EP meetings. In addition, the SDCA EPs serve as mentors for other EPs to teach cutting-edge techniques.

Here are some accomplishments of our outstanding EP team

Meet our team of Electrophysiologists


Electrophysiologist Daniel Alyesh MD Daniel Alyesh, M.D.

William Choe, M.D.

Electrophysiologist Roger Damle MD Roger Damle, M.D.

Ryan Jordan - South Denver Cardiology Ryan Jordan, M.D.

Jehu Mathew, M.D.

Nicholas Palmeri, MD

Sri Sundaram, M.D.


Sri Sundaram, MD Discusses Heart Rhythm Disorders

Learn more about heart rhythm disorders in this video. Sri Sundaram, MD, is an EP here at SDCA and discusses some of the treatment options and his passion for the field of Electrophysiology.

Your doctor may have recommended that you undergo an electrophysiology study. This is a procedure where the electrical system of your heart is examined. Arrhythmias, which are abnormal rhythms, slow or fast, can be further evaluated to aid in your treatment. You may have had a loss of consciousness (syncope) or have palpitations that require further investigation. There may be a concern that you are susceptible to a fatal rhythm such as ventricular tachycardia and this test may help in determining if you are at risk for this rhythm.

Arrhythmias and Palpitations

Heart palpitations are feelings of having a fast-beating, fluttering or pounding heart. Stress, exercise, medication, diet or, a medical condition can trigger them. Although heart palpitations can be worrisome, they’re usually harmless. In rare cases, they can be a symptom of a more serious heart condition, such as an irregular heartbeat (arrhythmia), that might require treatment.

Treatment for arrhythmia depends on the type and severity of the electrical heartbeat. Arrhythmias can be treated with medicine, minimally invasive procedures, electric shock treatment, or implantable devices.

In this video, Electrophysiologist Daniel Alyesh discusses palpitations and arrhythmias.

Electrophysiology (EP) Study
An electrophysiological study (EP study) is a test used to evaluate your heart’s electrical system and to check for abnormal heart rhythms. Natural electrical impulses coordinate contractions of the different parts of the heart. This helps keep blood flowing the way it should. This movement of the heart creates the heartbeat or heart rhythm.

During an EP study, your doctor inserts small, thin wire electrodes into the heart through a vein in the groin (or neck, in some cases).  The procedure may take up to three hours. You will meet several members of the electrophysiology lab team including physicians, nurses, and technicians during this procedure. They are all important in performing the procedure as well as keeping you safe and comfortable.

You will be brought to the electrophysiology laboratory, a sterile room which looks like a small operating room. You are placed on a table with an x-ray machine called fluoroscopy. An intravenous line will be placed in your arm. Through this intravenous line, you will be given sedative medicine throughout the study to make you comfortable. Both of your legs where your femoral vein and artery runs will be cleansed as a part of the procedure. Electrodes and large patches will be placed on your chest to monitor your heart’s rhythm. The femoral area on your leg will be made numb using lidocaine (which is similar to the medicine the dentist uses).



An electrophysiology study is not painful. There may be some discomfort at the femoral site where the catheters are inserted, but you will not feel the catheters in your body. Let the doctor know if you are experiencing discomfort, chest pain, shortness of breath, or palpitations.

Through these veins and possibly arteries in your leg, catheters are placed into the heart using an x-ray to watch its movement, and baseline measurements of your electrical system are made. In addition, electrical impulses are sent to stimulate your heart to evaluate your heart’s response, as well as to try and reproduce your arrhythmias.

You may have a rapid and dangerous heart rhythm which may be reproduced such as ventricular tachycardia or ventricular fibrillation. It may be possible that you will pass out. If this happens, the doctor will try and pace your heart out of the rhythm. Sometimes, you may need to be cardioverted (shocked) out of the rhythm.

After the procedure is completed, the catheters are removed and pressure will be held until the bleeding stops. You will be asked to lie flat on the bed without moving your legs for up to four hours. The doctor will talk with you and your family regarding the results of the study. Depending on the results of the test, you may be discharged home afterward.

Overall, an electrophysiology study is a safe procedure. There are risks involved in having this study performed like any other invasive procedure. The risks include damage and bleeding of the vessels where the catheters are inserted and puncturing the heart wall with the catheters causing bleeding around the heart sac and infections. Blood clots and strokes have been reported, and deaths from the procedure are rare.

Why might I need an EP study?

There may be other reasons for your healthcare provider to recommend an EP study.


South Denver Cardiology’s expert EP physicians were the first in the state and region to perform A-fib cardiac ablations without the use of fluoroscopy x-ray, saving the patient from high doses of radiation. 

Ablation is a procedure done in conjunction with the electrophysiology study. If you have a fast arrhythmia that you and your doctor have decided needs to be cured, an ablation may be recommended. After the electrophysiology study is performed, an ablation may be also performed at the same time using the catheters. Through one of the special catheters, radiofrequency energy can be delivered through its tip and a very small area of tissue destroyed.

There are risks involved with radiofrequency ablation in addition to the risks of the electrophysiology study. If the AV node (the connection between the upper chambers and lower chambers) is damaged, you may need a pacemaker.

Performing the ablation requires an additional 2 to 4 hours and the total electrophysiology study and ablation may take up to 6 to 8 hours. Because of the length of the procedure and sedation during the procedure, you will most likely stay overnight and be discharged the following day.

South Denver Cardiology’s expert EP physicians were the first in the state and region to perform A-fib cardiac ablations without the use of fluoroscopy x-ray, saving the patient from high doses of radiation. 

A pacemaker is a device that treats slow heart rhythms (bradycardia). The small generator is placed surgically under your skin just below the collarbone. There are one or two wires connected to the generator which go through the blood vessel into your heart. Their electrical impulses are delivered to your heart when needed.


 Automatic Implantable Cardioverter Defibrillator (AICD)
Automatic Implantable Cardioverter Defibrillators or (ICD) are for treating rapid life-threatening rhythms. The device is similar to pacemakers, only in addition to treating slow heart rhythms, they treat rapid ones as well. The device generator is larger than the pacemaker. One or two wires will be placed in your heart through blood vessels. There the device can watch every heartbeat and deliver therapies, including shocks, when needed.


If your cardiologist has recommended an ICD for you, we want you to be as informed as possible. We encourage you to visit the Colorado Program for Patient-Centered Decisions website. This site is for patients considering an ICD who are at risk for sudden cardiac death. This website will lead you step-by-step through some information on ICDs that may be helpful. We also hope this will make talking to your doctor easier.



Learn more about Electrophysiology on our Arrhythmia Clinic page.