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Characteristics, management, and midterm outcome in infants with atrioventricular nodal reentry tachycardia
G J Gross1, M R Epstein, E P Walsh
1Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA.
Insights
Atrioventricular nodal reentrant tachycardia (AVNRT) is rare in infants but generally benign. While digoxin shows limited long-term benefit, most infants achieve good outcomes, though some symptoms persist beyond infancy.
Area of Science:
- Pediatric Cardiology
- Electrophysiology
- Cardiac Arrhythmias
Background:
- Atrioventricular nodal reentrant tachycardia (AVNRT) is a common supraventricular tachycardia (SVT) mechanism in adults.
- AVNRT is infrequently documented in infants within their first year of life.
Purpose of the Study:
- To investigate the characteristics, management strategies, and outcomes of infants diagnosed with AVNRT.
- To understand the clinical course of AVNRT in the pediatric population.
Main Methods:
- Retrospective review of electrophysiologic studies conducted between January 1988 and June 1996.
- Identification and analysis of 15 infants diagnosed with AVNRT at a mean age of 58 days.
- Evaluation of long-term medical therapy (digoxin, beta-blockers, class III agents) and radiofrequency ablation outcomes.
Main Results:
- Fifteen infants with AVNRT were identified, with 5 cases associated with structural cardiac anomalies.
- Typical AVNRT was observed in 14 patients, and atypical AVNRT in 4.
- Long-term therapy included digoxin (13 patients), beta-blockers (6), class III agents (3), and radiofrequency ablation (2). AVNRT remained inducible in 6 asymptomatic patients post-therapy.
Conclusions:
- AVNRT diagnosed in infancy typically follows a benign course with favorable outcomes.
- A subset of infants may experience persistent symptoms beyond infancy, and digoxin's long-term efficacy is questionable.
- Inducibility of AVNRT in asymptomatic patients warrants further long-term follow-up to determine clinical significance.
Abstract:
Atrioventricular nodal reentry is a commonly recognized mechanism of supraventricular tachycardia (SVT) in adults, but is only rarely documented in the first year of life. The aim of this study was to elucidate characteristics, management, and outcome in infants with atrioventricular nodal reentrant tachycardia (AVNRT). Electrophysiologic studies performed between January 1988 and June 1996 were reviewed. Fifteen infants with AVNRT at 58 +/- 27 days (mean +/- SEM) were identified. Five had AVNRT detected following palliation of structural cardiac anomalies, including 4 with critical obstructions to left ventricular outflow. Typical AVNRT (ventriculoatrial interval 49 +/- 5 ms) was observed in 14 of 15 patients and atypical AVNRT (ventriculoatrial interval 191 +/- 22 ms) in 4 of 15. All patients received long-term therapy, beginning with digoxin in 13. Eight had symptomatic recurrences on digoxin and 6 of these were given beta blockers, with satisfactory control in 4. Three patients were controlled with class III agents, and 2 underwent slow pathway radiofrequency modification at ages 4.1 and 6.7 years, respectively. AVNRT was still inducible in 6 of 6 asymptomatic patients who underwent follow-up atrial stimulation studies after discontinuation of medical therapy. All 15 patients were alive with either absent or well-controlled AVNRT at age 45 +/- 7 months. We conclude that the course and outcome of AVNRT diagnosed in the first year of life are generally benign, but that a minority of patients have symptoms persisting beyond infancy. Digoxin is of questionable benefit in long-term control. AVNRT often remains inducible in asymptomatic patients, although the significance of this finding remains to be determined by long-term follow-up.