[Clinical analysis of right atrial appendage aneurysms complicated by atrial tachyarrhythmias in three children]

Objective: To investigate the clinical features and results of treatment for right atrial appendage aneurysms complicated by atrial tachyarrhythmias in children. Methods: This retrospective study included three children with right atrial appendage aneurysm complicated by atrial tachyarrhythmias (aged 1.0 to 5.3 years, weight 10 to 17.1 kg) who were hospitalized at the Pediatric Cardiology Department (Heart Center) of the First Hospital of Tsinghua University (Beijing Huaxin Hospital) during the period from January 2016 through April 2018. The patients' clinical features, the results of electrocardiogram (ECG) and echocardiography, the effects of therapeutic interventions (antiarrhythmics, radiofrequency ablation, and surgical resection of right atrial appendage aneurysm) and the results of pathological assessment were analyzed. Results: Three cases of right atrial appendage aneurysm were diagnosed at 36 weeks of gestational age, 1 month and 4 months after birth respectively. In two cases, ECG showed alternating episodes of atrial tachyarrhythmias including atrial tachycardia, atrial flutter, and atrial fibrillation, and echocardiography showed aneurysmal dilatation of right atrial appendage. These two cases underwent right atrial appendage aneurysm resection. In the remaining one case of atrial tachycardia, echocardiography did not visualize important lesions in the right atrium, thus the intracardiac electrophysiologic study and radiofrequency ablation were performed; and focal atrial tachycardia originating from the apex of right atrial appendage was mapped but failed to be ablated; consequently, the patient received the right atrial appendage resection, in which the right atrial appendage aneurysm was found. Preoperative multiple antiarrhythmics showed only modest or no efficacy for all the three cases. The atrial tachyarrhythmias disappeared in all the three cases after right atrial appendage aneurysm resection. Postoperative atrial tachycardias associated with new foci of impulse formation developed in two cases. These two patients reverted to normal sinus rhythm and remained in this rhythm by using antiarrhythmics. Pathological assessment showed cystic dilation of parts of atrial cavity, fibrosis of cyst wall, generalized fibrosis of atrial myocardium combined with myocardial atrophy and cystic dilation, as well as uneven myocardial thickness with generalized myocardial interstitial fibrosis. Conclusions: For patients with congenital right atrial appendage aneurysm, atrial tachyarrhythmias might develop during fetal stage or early postpartum period. Reliance on echocardiography might often lead to the missed diagnosis. These patients with atrial tachyarrhythmias responded poorly to antiarrhythmics. Radiofrequency ablation might be associated with a high risk and limited efficacy. Surgical resection of right atrial appendage aneurysm showed satisfactory results and should be highly recommended.