Ablation Therapy of Supraventricular Tachycardia in Elderly Persons

Leonard S. Dreifus, MD; Scott J. Pollak, MD

Disclosures

Am J Geriatr Cardiol. 2005;14(1):20-25. 

In This Article

Abstract and Introduction

Ablation of supraventricular tachycardia in elderly persons presents a challenging problem to electrophysiologists. Friable cardiac structures, prone to catheter perforation, comorbid cardiovascular disease, and the propensity to develop atrial fibrillation and thromboembolic complications, place these patients at high risk. Newer techniques for cardiac mapping and ablation, the establishment of precise ablation lines, and safer approaches to the ablation mechanism (particularly for atrial fibrillation) are presented in this review. In addition, a novel rapid ablation method to permanently cure atrial ventricular nodal re-entry tachycardia is demonstrated.

Supraventricular arrhythmias are common but persistent. As opposed to ventricular mechanisms, they are rarely life threatening; however, they present significant problems in patient management. Atrial flutter and fibrillation are especially important because stroke represents a major complication due to embolization. A careful history and physical examination—especially noting abnormal venous pulsations in the cervical neck region—are useful in the identification of specific mechanisms.

Persistence of tachycardia may lead to dilated cardiomyopathy and congestive heart failure. Ablation has proven highly successful and often cures tachycardia, although pharmacological therapy can be used for the acute onset of the tachycardia. In certain instances of infrequent episodes of tachycardia and in those persons without severe symptoms, long-term pharmacologic therapy is preferable. In these patients, "a pill in the pocket" may suffice for chronic management.

Frequently, evidence of tachycardia is difficult to document. Use of a Holter monitor, loop recorder, or an implantable recorder can be helpful to identify the ectopic mechanism. Arrhythmia-related symptoms are frequent and troublesome to patients, often including fatigue, dyspnea, dizziness, and presyncope. Patients often are symptomatic, even with single premature beats or nonsustained atrial arrhythmias.

Periods of paroxysmal rapid heart action, having a sudden onset and offset, are designated as paroxysmal supraventricular tachycardia, and are most frequently due to atrioventricular re-entry tachycardia (AVRT) or atrioventricular nodal re-entry tachycardia (AVNRT). Tachycardias, which respond to vagal maneuvers or other cholinergic agents like adenosine, are usually due to re-entry and involve the compact region of the atrioventricular (AV) node. Vagal maneuvers producing a transitory AV block suggest focal atrial tachycardias. Recently, the American Heart Association, the American College of Cardiology and the European Society of Cardiology published guidelines for the identification and management of the supraventricular tachycardias (SVTs).[1] Ablation of SVTs has been reserved for intractable arrhythmias and highly symptomatic patients in whom pharmacologic therapy has failed. Due to comorbidities and the sclerotic and fragile nature of the cardiac structures in elderly persons, ablation may be associated with increased complications, including catheter perforation and embolization.

Several classifications of atrial arrhythmias have been proposed, and each illustrates important clinical and electrophysiologic information that is useful to clinicians ( Table I ). All patients with a wide QRS tachycardia of unknown origin, those resistant or intolerant to pharmacologic therapy, and those with the Wolff-Parkinson-White (WPW) syndrome should be referred to a cardiac rhythm specialist. Electrophysiologic and precise mapping studies are mandatory for successful ablation procedures. Ablation of supraventricular arrhythmias has been extremely effective in more than 96% of cases. Several examples of ablative solutions for ectopic tachycardia will be discussed. The technical aspects of three-dimensional electroanatomical mapping using the non-fluoroscopic-based CARTO system (Biosense Webster, Diamond Bar, CA) used in these ablation studies is summarized below. The location sensor is incorporated into a mapping catheter to allow automatic and simultaneous acquisition of the catheter tip electrogram and its three-dimensional location coordinates. The mapping system acquires the location of the catheter tip electrode with a single location at a fixed time during the cardiac cycle and reconstructs a three-dimensional electroanatomical map of the heart in real time without the use of x-rays.

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