catheter ablation


Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.

Catheter Ablation

 

Definition

Catheter ablation of an irregular heartbeat involves having a tube (a catheter) inserted into the heart through which electrical energy is sent to either reset the heartbeat or stop the heart from beating so a mechanical pacemaker can be put in place.

Purpose

Irregular heartbeats can occur in healthy people without causing any dangerous symptoms or requiring medical attention. Slight changes in the normal patterns of heartbeats often reset themselves without notice.
But when the heartbeat is greatly disrupted—either because of traumatic injury, disease, hypertension, surgery, or reduced blood flow to the heart caused by blockages in the blood vessels that nourish the heart—the condition must be recognized and treated immediately. Otherwise, it can be fatal.
Various drugs can be used to control and help reset these abnormal heart rhythms (arrhythmias). The technique of catheter ablation (meaning tube-guided removal) is used to interrupt the abnormal contractions in the heart, allowing normal heart beating to resume. Atrial fibrillation and flutter and Wolff-Parkinson-White syndrome are two of the most common disorders treated with catheter ablation.

Precautions

The improper correction of abnormal heartbeats can cause additional arrhythmias and can be fatal. Abnormalities in different areas of the heart cause different types of irregular heartbeats; the type of arrhythmia must be clearly defined before this procedure can be properly done.

Description

Catheter ablation involves delivering highly focused heat (or radio frequency energy) to specific areas of the heart. Radio frequency energy is very rapidly alternating electrical current that is produced at the tip of the catheter that is placed inside the heart. At the same time as the catheter is inserted, a second electrode is placed on the patient's skin. When the catheter is energized, the body conducts the energy from the catheter's tip, through the heart and to the electrode on the skin's surface, completing the circuit.
Although very little electricity is given off by the catheter, the instrument does generate a large amount of heat. This heat is absorbed by the heart tissue, causing a small localized burn and destroying the tissue in contact with the catheter tip; in this way, small regions of heart tissue are burned in a controlled manner. This controlled destruction of small sections of heart muscle actually kills the nerve cells causing the irregular heartbeat, stopping the nerve signals that are passing through this section of the heart. This usually causes the irregular heartbeat to be reset into a normal heartbeat.

Preparation

People can undergo this procedure by having general anesthesia or by taking medicines to make them relaxed and sleepy (sedatives) along with painkillers. Once the type of irregular heartbeat is identified and these medicines are given, the catheter is inserted through a blood vessel and into the heart. Importantly, correct placement of the catheter is visualized by using a specialized type of x-ray machine called a fluoroscope.

Aftercare

Being sure the patient is comfortable during and after this procedure is very important. However, because each person may have a different arrhythmia and possibly other medical problems as well, each patient's needs must be evaluated individually.

Risks

Overall, fewer than 5% of people having this procedure experience complications. The most common complications are usually related to blood vessel injury when the catheter is inserted and to different heart-related problems due to the moving of the catheter within the heart. However, in general, this technique is safe and can control many different heart arrhythmias.

Normal results

Depending upon the type of irregular heartbeat being treated, either the normal heartbeat resumes after treatment or the ability of the heart to beat on its own is lost, requiring the insertion of a pacemaker to stimulate the heart to beat regularly.

Key terms

Fluoroscope — A specialized x-ray machine used to visualize the placement of the catheter when attempting to correct irregular heartbeats.
Pacemaker — An electrical device that has electrodes attached to the heart to electrically stimulate the heart to beat normally. Pacemakers can be internal (placed under the skin) or external, with the electrodes placed on the skin or threaded through a tube placed into the heart.

Abnormal results

Additional irregular heartbeats can occur as a result of this procedure, as can damage to the blood vessels that feed the heart. Because this procedure requires the use of the x-ray machine called a fluoroscope, there is exposure to x-ray radiation, but it is doubtful that this is harmful in adult patients. The risk versus benefit is considered with pediatric patients.

Resources

Organizations

American Heart Association. 7320 Greenville Ave. Dallas, TX 75231. (214) 373-6300. http://www.americanheart.org.

ablation

 [ab-la´shun]
1. separation or detachment; extirpation; eradication.
2. removal, especially by cutting with a laser or electrocautery.
catheter ablation radiofrequency ablation.
endometrial ablation removal of the endometrium; methods used include radiofrequency, electrical energy, lasers, and hot and cold liquids.
radiofrequency ablation (radiofrequency catheter ablation) destruction of an accessory conduction pathway or other troublesome area of dysrhythmia by means of unmodulated high frequency alternating current delivered by a bipolar or unipolar catheter. The current causes heat with tissue destruction and formation of scar tissue to block the pathway or dysrhythmic area. Transvenous radiofrequency ablation has been successful in treatment of supraventricular tachycardia and is an attractive option to surgery. Called also catheter ablation.

catheter ablation

catheter ablation

A minimally invasive procedure for the treatments of supraventricular tachcardia. The procedure, performed through an intravenous catheter uses radio-frequency energy to heat and destroy a small amount of heart tissue after multipolar catheter electrode investigation has revealed the arrythmia mechanism. The scar left acts as an electrical bnarrier
References in periodicals archive ?
CACAF involved 137 patients with paroxysmal or persistent AF refractory to two or more different antiarrhythmic agents who were randomized to catheter ablation plus antiarrhythmic drug therapy or antiarrhythmic drug therapy alone.
23: Lasso catheter ablation of atrial fibrillation and connecting cable.
The growing use of catheter ablation procedures to eradicate AF will result in increased use of antiarrhythmic agents for several reasons.
Catheter ablation is less successful in patients with longstanding, persistent AFib.
2 issue of The Lancet confirmed the efficacy of catheter ablation before ICD implantation in patients with Vtach and poor left ventricular ejection fraction resulting from prior heart attack.
By the new guidelines, patients have to fail only one drug before they become eligible for catheter ablation.
Cardiac catheter ablation procedures are used to treat a variety of cardiac arrhythmias including atrial fibrillation and atrial flutter.
Patients with left atrial enlargement, long-standing persistent AFib, and anatomic barriers like abnormal veins in the leg are good candidates for epicardial ablation but not catheter ablation," says Marc Gillinov, MD, a cardiac surgeon at Cleveland Clinic's Heart & Vascular Institute.
There is evidence that catheter ablation is more successful in people who have paroxysmal AFib (in which each episode lasts less than seven days and stops spontaneously) than it is in people who have persistent AFib (in which each episode lasts more than seven days, and only stops with cardioversion).
Ongoing large randomized clinical trials, such as Catheter Ablation vs.
1) Current treatments for AFib are cardioversion, prescription medication for management of rate and/or rhythm control, and, when all else fails, surgery or catheter ablation.