Supraventricular Tachycardia Due to Multiple Atrial Ectopic Foci: A Relatively Common Problem

Abstract

Multiple Atrial Ectopic Foci. Atrial ectopic focus is a common mechanism for chronic incessant supraventricular tachycardia in children. The majority of patients require treatment because of symptoms or tachycardia‐induced cardiomyopathy. Management with traditional drugs fails to restore sinus rhythm and surgery has heen thought to be curative. We have had 54 patients with atrial ectopic focus tachycardia; 40 right atrial (36 with normal P waves simulating sinus tachycardia), and 14 left atrial. Surgical treatment of tachycardia was performed in 28 patients; all 28 had a single abnormal P wave axis before surgery, had mapping in the electrophysiology lab, and were thought to have a single focus. However, in 14/28 (50%) after surgical removal of this focus, additional foci became apparent. In 11/14, the next focus appeared during surgery; between 3–15 additional foci were identifled and surgically treated. This resulted in cure in 9/11, but 2/11 despite almost total atrial disconnection, continued to have atrial ectopic focus tachycardia. The other three patients with multiple foci had atrial ectopic focus tachycardia recur with a diflPerent P wave axis from 1 week to 2 months postoperatively. Since the overall initial success rate for multiple foci was different from single foci, patients with multiple foci and single foci were compared to try to predict multiple foci. Patients with multiple foci had: (1) the same incidence of cardiomyopathy (78%); (2) faster maximum atrial rate on Holter (89% of multiple foci had a rate faster than 160/min vs 43% of single foci, (P < 0.05); (3) faster minimum atrial rate on Holter (89% of multiple foci had a minimum rate faster than 70/min vs 0% single foci, (P < 0.05); and (4) different preoperative electrocardiogram (0% multiple foci had left atrial P waves vs 44% of single foci, (P < 0.025). In conclusion: (1) approximately half the patients with atrial ectopic tachycardia had multiple foci; (2) surgical treatment of multiple foci was less successful than single foci, although with improvement in surgical techniques, even multiple foci were successfully eliminated by surgery, and surgery was successful in 100% of the last 10 cases; (3) multiple foci were unlikely with left atrial P waves and slower atrial rates. We speculate that atrial ectopic focus tachycardia may have different etiologies: multiple foci may be due to extensive atrial disease such as that found in primary cardiomyopathy or after myocarditis, whereas single foci may be a developmental aberration. (J Cardiovasc Electrophysiol, Vol. J, pp. 132–138, April 1990)