Cardiac Electrophysiology Consultants of South Texas, P.A.

Medical Center Tower I
7950 Floyd Curl Drive
Suite 803
San Antonio, TX 78229
tel: 210-615-9500
fax: 210-615-9600
email: office at
Specializing in the compassionate care of people who suffer from abnormalities of the electrical system of the heart Current Insurance Plans: We accept most major commercial insurance plans. Please call for details.
Medicare: We have opted out of Medicare, and are happy to care for Medicare beneficiaries on an affordable cash basis. Note: Federal law prohibits signing the Federally-mandated opt-out contract with a Medicare beneficiary who is in an emergency situation.
No insurance? No problem! Consider our affordable Fee for service (direct pay).
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General information about the heart for patients, their family members, and concerned laymen

  The Arrhythmias Section Contents
Treatments for the Arrhythmias
     What to do if you have an arrhythmia
The symptoms of a fast heart beat (tachycardia) usually are a combination of palpitations, faintness, and/or shortness of breath. In some cases, the person will notice only "pounding" of the heart. In other cases, the person may pass out with very little warning. The symptoms of a slow heart beat (bradycardia) are similar except that people usually do not notice palpitations or "pounding".

If you are having any these symptoms and you do not know why, you should go to a medical facility while you are experiencing the abnormal rhythm so that an electrocardiogram ("12-lead ECG") can be obtained. The 12-lead ECG of the fast heart rhythm is the best way to find out just what kind of fast heart rhythm you are having.

The general rule for arrhythmias is to act according to the severity of the symptoms. If you feel bad, seek medical help. If you feel really bad, call your local Emergency Medical Service (usually by dialing 911 on the telephone). This advice sounds trite, but in an emergency the simplest strategies are best.

Below is some information that may help you but may hurt you instead. Please ask your doctor whether you can and/or should use any of the information below (or anywhere elsewhere on this or other Internet sites as well).

If your heart is going so slowly that you feel faint, you can lie down with your feet elevated (for example, on a chair or bed). This will increase the amount of blood returning to your heart due to gravity, and may help maintain your blood pressure. If this does not help, you can cough hard about once a minute. The pressure of the cough on the heart will force some blood out. This is a measure of last resort, so make sure someone is calling for help.

If your heart is going so fast that you feel faint, you can lie down with your feet elevated (for example, on a chair or bed). This will increase the amount of blood returning to your heart due to gravity, and may help maintain your blood pressure. You can also try the Valsalva maneuver or carotid sinus massage, which are often effective for certain types of fast heart rhythms ( AV nodal reentrant tachycardia and AV reentrant tachycardia). It is best to review this maneuver with your doctor before you may actually need it. Finally, your doctor may have given you pills to take in case your heart went too fast. Remember that these pills will usually take 30-45 minutes to take full effect because the medicine has to be absorbed from your stomach and intestines into the blood stream.

Drug Therapies
Drugs are often effective for the treatment of tachycardias. Unfortunately, all of the effective antiarrhythmic drugs have side effects, are expensive, and require the person to remember to take them on at least a daily basis. The topic of drug therapies of tachycardias is vast, but there are several general principles that can be stated.

The generally used classification of antiarrhythmic drugs is that of Vaughn-Williams, who categorized drugs by their major effects on the heart.

Category Examples of Drugs Major Side Effects
IA quinidine, procainamide, disopyramide torsades de pointes, sudden death
IB lidocaine, mexiletine few major side effects
IC flecainide, propafenone torsades de pointes, sudden death
II beta-blocking drugs few major side effects
III amiodarone, ibutilide, sotalol, dronedarone torsades de points, sudden death - but less than with the Class I agents
IV calcium-blocking drugs few major side effects

As you can see, the major side effects get your attention. The drugs that have those side effects are more effective than those that don't. It is important to remember that most people can take these drugs and feel just fine. When an adverse outcome happens, though, it is sometimes very bad. This is why doctors are very careful when they prescribe antiarrhythmic medications. Often they will consult with a clinical cardiac electrophysiologist, a specialist physician who has extensive training in the diagnosis and treatment of abnormal heart rhythms.

Catheter-mediated Radiofrequency Ablation
Radiofrequency ablation is a technique for treating tachycardias. It has been used widely since about 1990, and is now the treatment of first choice for many of the supraventricular tachycardias and several types of ventricular tachycardia. Its use for the cure of atrial fibrillation is becoming routine for some types of cases, and its use for ventricular tachcardias related to myocardial infarction is routine but not very successful because of the nature of the disease process (so an ICD is usually implanted in patients with this problem).

In this technique, a long, thin, solid tube (catheter) with wires inside and electrodes near its tip is inserted into the body through a vein in the thigh, shoulder, or neck. The tip is positioned inside the heart next to the abnormal heart tissue that is responsible for the tachycardia. Then, a small amount (about 50 watts) of energy is applied to the heart between the tip electrode and a skin patch that is usually placed behind the left shoulder. This energy heats up and thus dries out the heart tissue that is within about 5 millimeters of the tip. After about 30 to 60 seconds of heating, this tissue is no longer alive and cannot cause tachycardia any more.

Although the actual ablation takes only a minute, the procedure often takes 4 to 10 hours. The reason is that it is time-consuming to identify the exact tissue in the heart that is responsible for a tachycardia and to make sure that all of this tissue has been ablated completely.

Ablation is performed by specialists known as clinical cardiac electrophysiologists.

The cardiac rhythms that can often be cured by radiofrequency ablation include atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular tachycardia (AVRT) that uses an accessory bypass tract for retrograde conduction, atrial tachycardias that occur in otherwise-normal hearts and also in hearts that have had prior surgery, atrial flutter, and some kinds of ventricular tachycardia that occur in otherwise-normal hearts. The first three rhythms are often grouped together with the term "supraventricular tachycardia", although this term can also be used to include atrial flutter and atrial fibrillation.

As noted above, two kinds of rhythms can sometimes be cured by radiofrequency ablation but often cannot be. Ventricular tachycardia occuring in hearts that have suffered myocardial infarction can be cured in about 25% of cases in which radiofrequency ablation is tried. Most electrophysiologists implant cardioverter-defibrillators in all of these patients because recurrence of the rhythm weeks or months after the ablation effort can prove fatal. Ablation for cure of atrial fibrillation is a very active research topic in the field of clinical cardiac electrophysiology, and in recent years has been in routine clinical use with reported long-term success rates of 50-80%.

The cardiac rhythms that cannot be cured but whose symptoms can be improved by radiofrequency ablation include any of the supraventricular tachycardias, including atrial flutter and atrial fibrillation. The improvement comes at a price, however. When the tachycardia cannot be controlled with medication and cannot be cured by ablation, the symptoms due to the rhythm (but not the rhythm itself) can often be controlled by one of two procedures.

  • Intentional destruction of the AV node itself. This procedure, AV junctional ablation, disconnects the upper and lower chambers of the heart electrically, and requires implantation of a permanent pacemaker on the same day. This drastic step is currently the only routinely available method that offers complete control of the rapid heart rate that can occur with atrial fibrillation, and this rhythm is the one for which it is used most commonly.
  • Ablation of the slow AV nodal pathway. This procedure is the same one that is used for cure of AV nodal reentrant tachycardia. For uncontrollable atrial fibrillation and other supraventricular tachycardias, this procedure offers some of the benefit of AV junctional ablation without the need for implantation of a permanent pacemaker. The way it works is the following: the heart in most people comes with two parts to the AV node. The "fast" AV nodal pathway conducts rapidly but takes a long time to recover enough to conduct the next heart beat. The "slow" AV nodal pathway is a backup pathway that conducts slowly but can recover very quickly. At most heart rates, people use only the fast pathway. When the heart is going very rapidly (during vigorous exercise, for example), they often use the slow pathway because the fast pathway can't recover fast enough between heart beats. When the slow pathway is removed by ablation, the person almost never can tell the difference at usual heart rates (even during vigorous exercise to, say, a heart rate of 180-200 beats per minute). If a very rapid heart rate (say, to 250 bpm) occurs in the atria, however, the ventricles will go more slowly than they would with an intact slow pathway.

    In older people, who are the ones who usually develop sustained atrial fibrillation, the fast pathway does not conduct as rapidly as in young people, so the maximum heart rate can often be reduced to a range that is tolerable. There are two problems with this procedure for atrial fibrillation, in which we have the most experience: first, when the procedure is continued until the heart rate in atrial fibrillation is reasonable (say, 130 bpm during infusion of isoproterenol, which speeds up the heart rate), about 20% of patients get complete heart block and require immediate implantation of a permanent pacemaker. Second, people who have this procedure often don't feel as well as those who go ahead and have AV junctional ablation and pacemaker insertion. The reason seems to be that the heart rate is still erratic because the ventricular rhythm still follows the irregularly irregular atrial fibrillation. By contrast, people who have AV junctional ablation and pacemakers have regular rhythms because the pacemakers set the heart rate for them.

Long-term complications include recurrence of the original rhythm or occasional creation of new related rhythms (for example, increasing the rate of occurrence of atrioventricular tachycardia using a left sided pathway following ablation of the left bundle branch with failure to ablate the pathway itself, which sometimes happened in the early years of ablation) and rare skin burns due to radiation used during procedures that took a very long time.

The radiation used during the ablation procedure can theoretically cause cancer, especially breast cancer in women. However, no one knows whether this is a real risk or not, and we won't know for quite some time because cancer caused by low levels of radiation usually takes decades to appear.

Hyperlipidemia doesn't affect the supraventricular rhythms that are the usual targets of ablation. When ablation is used for the type of ventricular tachycardia that occurs in people who have had myocardial infarction, however, control of hyperlipidemia is quite important to prevent recurrent infarction.

Implantable Cardioverter-Defibrillators
Implantable cardioverter-defibrillators are devices that are placed under the skin (as are pacemakers) to treat ventricular tachycardia and ventricular fibrillation. They have been in general use since 1985, and have proven safe and effective for treating patients who have suffered or are likely to suffer sudden cardiac death due to those rhythms.

The difference between pacemakers and implantable cardioverter-defibrillators is that pacemakers prevent the heart from beating too slowly, while implantable cardioverter-defibrillators prevent the heart from beating too fast due to certain abnormal fast heart rhythms.

In recent years, the devices have been getting smaller and more capable. The original devices required open chest surgery for implantation. The most recent devices can almost always be placed under the skin of the shoulder, as are pacemakers. The batteries in the original device lasted about 18 months. The batteries implanted in the 2000s up 2010 were predicted to last 6 to 8 years, and starting in about 2010, battery service durations up to 10-12 years are predicted by the manufacturers.

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