THMG Specialties

The doctors at Texas Heart Medical Group are experts in their fields. Our specialties are broad and comprehensive, covering every aspect of heart health from prevention to surgical treatment.

Heart Monitors

Event Monitoring

What is it?

Heart monitors are devices that are worn by the patient and are used to record the electrical activity of the heart. The goal of these monitors is to help identify abnormal heart rhythms that may be the cause of symptoms such as palpitations, “heart racing”, dizziness, lightheadedness, chest pain or loss of consciousness (called “syncope”). The choice of monitor that your doctor recommends depends on the frequency and/or duration of your symptoms. This heart monitor will be mailed to your home. When you receive the monitor, follow the instructions provided.

What do I do?

Event monitors are used to assessing symptoms that occur infrequently, such as a couple of times per month. When you notice your symptoms, you push the button on the monitor (either an event monitor or a “heart card”). The monitor then records your heart rhythm for a brief period of time.

This tracing reveals the heart rhythm that is present when you have your symptoms. A few of these tracings can be stored on your monitor. You then call an 800 telephone number (which is provided to you).

This phone is operated by personnel that helps you send the recorded tracings over the phone. The tracings will be forwarded to Texas Heart Medical Group and will be reviewed by your physician.

What will happen?
Tracings will be reviewed by your physician.

Texas Heart Medical Group will contact you if tracings have any life-threatening rhythms noted and give any further instructions.

How long does it take?
The event monitor will be worn for up to 30 days. The package will include electrodes and batteries for the monitor, with instructions on use provided.

Post Procedure Instructions:

You will receive the results of the monitor within 7-10 days of returning the monitor.


What is it?

Holter monitors are useful for any patient whose symptoms occur frequently, on a daily basis. It will need to be worn constantly for a period of either 24 or 48 hours, during which the monitor continuously records your heart rhythm activity, regardless of whether you feel symptoms.

What do I do?

You will wear several adhesive patches that are then attached to the monitor by electrode wires. These will be placed in proper position by the staff of Texas Heart Medical Group.

What will happen? 

You will be asked to keep a written diary of symptoms and events that occur while you are wearing the Holter monitor. When you return to the clinic, the monitor will be removed and a printout of all of your heart’s activity during the recording period and the symptoms noted on the diary will be given to your physician.

Post Procedure Instructions:

The important point about Holter monitors is that it records all arrhythmias: those that may cause symptoms as well as those that are minor and do not cause symptoms. For the arrhythmias that do not cause symptoms, the majority do not require any specific therapy.


Frequently Asked Questions About ICDs

Q: If someone is touching me when I am shocked, will they too receive a shock?
A: No.

Q: How are the specific parameters for my ICD measured and changed?
A: The ICD contains a computer chip that can be evaluated and reprogrammed in a painless manner. By using a hand-held device placed over your clothes, on top of the ICD, we can retrieve information about the ICD battery, leads as well as alter specific features for your ICD.

Q: How long will my ICD device and leads last?
A: A typical ICD battery life is 3-5 years. The ICD leads have a longevity of approximately 7-10 years. Both the battery life and the performance of the leads will be monitored through frequent evaluations by Texas Heart Medical Group, or follow up can be coordinated with your local hospital or cardiologist.

Q: What happens when the ICD battery becomes low?
A: When the ICD battery is measured low through routine follow up with Texas Heart Medical Group, you will be notified and scheduled for replacement of the ICD generator. Replacement of the ICD generator is a simple outpatient procedure. The electrophysiologist will open the ICD skin pocket and unplug the leads. The leads will be tested to make sure they function properly. After testing, the leads are connected to the new ICD pulse generator, tested and the pocket is closed. The entire operation often takes less than an hour.

Q: What should I do if I hear “beeping” from my ICD?
A: If you hear an audible “beep” from your ICD, please contact the office, Monday – Friday 8:30AM – 5:00PM at 713-790-9401. There are many defibrillators that emit a tone when there is a parameter that needs to be assessed. In general, this is not an emergency.

Q: What should I do if I feel a thumping in my chest?
A: Sometimes patients with a biventricular ICD can experience an unusual sensation of “thumping” on the left side of their chest, usually most pronounced if they are in a certain position such as when they roll onto their left side. This thumping may be due to the electrical impulse from the biventricular pacemaker causing stimulation of a nerve on the outside of the heart (called the phrenic nerve). This nerve travels to the diaphragm and can cause the diaphragm to beat, which creates these symptoms. Fortunately, this problem can be managed by reprogramming your ICD. You should contact our office the next working day, Monday – Friday 8:30AM – 5:00PM at 713-790-9401, but this problem usually does not require a visit to your emergency room.

Q: What should I do if I notice my ICD incision is red, swollen or that fluid is leaking from the incision site?
A: If you have these symptoms or changes along your ICD incision, we believe that it is important for you to contact your local physician (if you are out of town) or Texas Heart Medical Group to evaluate the ICD. This may be a simple matter of minor blood collection within the ICD pocket or it may be an early sign of an infection.

Q: What are the recommendations regarding driving with an ICD?
A: After an ICD is implanted, many patients are correctly concerned about their ability to safely operate a motor vehicle. Guidelines regarding when to return to driving are dependent upon why the device was implanted and whether the implanted device is a pacemaker or defibrillator.

Q: When can I return to work?
A: The decision when to return to work is based on the particular job and working environment as well as consideration of other heart issues. Please be certain that this issue is addressed by Texas Heart Medical Group before your discharge, or feel free to contact us. We are very familiar with providing documentation and forms if there is a need to provide information to your employer.

Q: Can an ICD prevent a heart attack?
A: No, an ICD cannot prevent a heart attack, which is due to a blockage in the blood flow to the heart muscle.

Q: Does an ICD treat other heart rhythm abnormalities like atrial fibrillation?
A: An ICD is designed to treat rapid heart rhythms from the bottom chamber of the heart as well as excessively slow heart rhythms that are treated with pacing therapies. However, an ICD does not treat rapid heart rhythm problems from the top chambers of the heart, such as atrial fibrillation.

Q: What type of interactions may occur with my ICD and a microwave, cell phone, store security devices, airport security or arc welding?
A: There is no interaction between a microwave and an ICD. We would prefer that you use a cell phone on the opposite side of your ICD but, in general, the likelihood of complications between an ICD and cell phone is quite low. When going through airport security, it is important that you inform the airport security personnel that you have an ICD. You will need to show your device ID card and you should be asked to be hand searched. An ICD pulse generator may be sensitive to anti-theft systems often found in stores and public libraries. These systems will not adversely affect the ICD if you walk through them in a normal manner without lingering near them. Arc welding can interfere with the function of an ICD, but this interaction depends on the type of arc welding that is performed. If you use an arc welder, please discuss this issue with your electrophysiologist.