Catheter ablation of accessory atrioventricular pathways (Wolff-Parkinson-White syndrome) by radiofrequency current

Article Abstract:

The normal function of the heart requires careful timing. Blood is pumped through the body by the contraction of the powerful muscular ventricles, but if the ventricles contract at the wrong time, the pumping of blood is inefficient. In the normal heart, the natural ''pacemaker'' rhythm begins the contraction of the atria, which fill the ventricles with blood. At the same time, an electrical signal begins to travel towards a stimulating node at the boundary of the ventricles; the time this travel takes provides the right timing for the contraction of the ventricles, to pump the blood throughout the body. Some patients, however, suffer from the presence of an accessory pathway. An accessory pathway may provide a course for the electrical stimulation to circle back, re-enter the stimulating pathways, and start another cycle of contraction prematurely. Several different types of such ''reentrant'' disorders exist; one such condition is called Wolff-Parkinson-White syndrome, and the net result is tachycardia, a much too rapid beating of the heart. The condition may be treated by surgery to simply destroy the accessory pathway and return the electrical regulation of the heart to normal (ablation). This destruction is often accomplished with high-voltage electrical current, which obliterates the unwanted accessory pathway but can also damage normal tissue and contribute to greater illness and death. However, research on 166 patients with a total of 177 accessory pathways has now shown that it is possible to accomplish the same goal using radiofrequency current with greater safety and effectiveness. A catheter containing the radiofrequency electrode is introduced into the major artery in the leg and gently guided until the tip is positioned within the chamber of the heart at the spot to be ablated. No more than three applications of radiofrequency current are necessary to accomplish the destruction of the unwanted electrical connection within the heart. The procedure was successful in 164 of 166 patients. The tachycardia returned in 15 patients, all of whom were successfully treated in a second operation. Six patients suffered complications of the procedure, but there were no fatalities. The results demonstrate that radiofrequency ablation is a safe and effective method for the treatment of Wolff-Parkinson-White syndrome. (Consumer Summary produced by Reliance Medical Information, Inc.)

Surgery, Tachycardia, Radio, Wolff-Parkinson-White syndrome

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Supraventricular tachycardia

Article Abstract:

Recent advances in the understanding and medical management of supraventricular tachycardia may improve heart function in patients with this disorder. Supraventricular tachycardia refers to any rapid heartbeat that is initiated and maintained by atrial or atrioventricular junctional tissue. Electrophysiologic studies using programmed electrical stimulation have increased the understanding and diagnosis of the disorder. The drug adenosine may control supraventricular tachycardia by blocking the atrioventricular nodal conduction. Calcium channel blockers and class I antiarrhythmia drugs may also be useful. Radiofrequency ablation may be recommended for patients who do not respond to drugs that block the atrioventricular nodal conduction. Radiofrequency ablation may be the best treatment for patients with the Wolff-Parkinson-White syndrome and atrioventricular reentrant tachycardia with symptoms.

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Treatment of supraventricular tachycardia due to atrioventricular nodal reentry by radiofrequency catheter ablation of slow-pathway conduction

Article Abstract:

Radiofrequency catheter ablation may be an effective treatment for patients with atrioventricular nodal reentrant tachycardia (AVNRT). AVNRT is a rapid heart beat caused by conduction of the electrical impulses of the heart through an abnormal pathway. Among 80 patients with AVNRT who were treated with radiofrequency catheter ablation, 78 experienced the elimination of or a decrease in conduction through the abnormal pathway. Treatment with this procedure did not disrupt conduction through the normal pathway of the heart. Patients were followed an average of 15 months after treatment, and none experienced a recurrence of AVNRT during the follow-up period. Among 32 patients who underwent a series of electrophysiological tests an average of four months after treatment, all had conduction through the normal pathway of the heart without AVNRT.

Ablation (Surgery), Cardiac catheterization, Heart catheterization

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