Abstract 4367114: Tachycardia-induced Cardiomyopathy from Incessant Atrial Tachycardia in a Teenager with Severe Pectus Excavatum

Description of Case: A 14-year-old male with a Haller Index of 6.1 was referred to cardiology clinic for evaluation of severe pectus excavatum (PE). He was asymptomatic but was incidentally found to have incessant atrial tachycardia (AT) with a left atrial focus predicted based on p wave morphology analysis on electrocardiogram. On echocardiogram, he had evidence of left atrial compression and moderate left ventricular systolic dysfunction, consistent with tachycardia induced cardiomyopathy. Initial medical therapy with ivabradine, flecainide, and atenolol led to rate control and subsequent improvement in left ventricular function but failed to terminate the arrhythmia. He underwent surgical repair of the PE. Postoperatively, left ventricular function normalized, but AT persisted despite continued escalation to ivabradine, sotalol, and flecainide. An electrophysiology study performed 8 weeks from surgical repair identified a focal AT arising from the left atrial posterior wall. The focus was successfully eliminated with radiofrequency ablation. He has since remained in sinus rhythm and off antiarrhythmic therapy with full recovery of ventricular function. Discussion: Pectus excavatum is the most common anterior chest wall deformity. Though often a benign, asymptomatic, cosmetic anomaly, PE has been associated with several cardiac effects including hemodynamic compromise and arrhythmias secondary to cardiac compression. To our knowledge, this is the first pediatric case of persistent, drug refractory AT requiring catheter ablation, despite surgical correction of the PE. The p wave morphology on electrocardiogram, left atrial deformity on echocardiogram, and intracardiac activation map of the AT focus in this case, support cardiac compression as the mechanism for AT. These findings suggest the potential for sustained atrial remodeling with subsequent arrhythmia in the context of PE and underscores the importance of cardiac screening in asymptomatic adolescents with severe chest wall deformities.