A Non-clinical Macroreentrant Right Atrial Tachycardia with Two Independent Loops: the Exception to the Rule of a Shared Mid-diastolic Isthmus in Double-loop Reentry

Abstract

This is a 34-year-old male patient with congenital ventricular septal defect and subvalvular aortic stenosis. At the age of 1, he underwent surgical closure of the ventricular septal defect, which involved surgical incision of the right atrium. At the age of 11, the subvalvular aortic stenosis was surgically corrected. Before this intervention, at the age of 8, he underwent right pneumectomy for hemoptisis due to congenital absence of the right pulmonary artery. Six months before the procedure he complained of two episodes of palpitations. These were documented by surface ECG as counter-clockwise typical atrial flutter, requiring DC-shock cardioversion to restore sinus rhythm. Subsequently, he was referred for an electrophysiology procedure while on sinus rhythm and in wash-out from antiarrhythmic drug therapy. Echocardiography showed neither residual shunts nor significant gradient in the left outflow tract; left ventricular function was preserved.