Focal Atrial Tachycardia in an Enlarged Right Antrium after Rastelli’s Operation: Ambiguous Mapping Data in Confict with the Orthodoxies

Abstract

This is a 39-year-old female patient with transposition of the great vessels and ventricular septal defect. At the age of 5, she underwent Rastelli’s operation at the Mayo Clinic. The surgical procedure included an external homograft conduit between the right ventricle and the pulmonary artery. Seven years later, she underwent another operation to replace the conduit. At the age of 35 years, she developed signs and symptoms of congestive heart failure, with enlargement of the right atrium and ventricle. Despite optimal medical therapy, she complained of palpitations due to atrial tachycardia and atrial fibrillation. The concomitant presence of life-threatening ventricular arrhythmias led to the implantation of a dual-chamber ICD. In the months prior to the procedure, despite therapy with amiodarone and beta-blockers, the patient developed atrial tachycardia of 400 ms cycle length with 1:1 atrioventricular conduction and incessant-iterative presentation. This accounted for severe functional limitations and worsening of heart failure. As shown in Fig. 1, two atrial tachycardia morphologies alternated with sinus rhythm/ atrial pacing in this patient. The first, more prevalent morphology showed positive P waves in the inferior leads, whereas the second morphology had negative P waves in the same leads. However, the presence of a right bundle branch block and 1:1 atrioventricular conduction greatly complicated analysis of the P wave morphology and onset in all the twelve leads.