Unusual Atrioventricular Reentry Tachycardia in Congenitally Corrected Transposition of Great ArteriesKey Teaching Points
A Novel Site for Catheter Ablation
This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
- atrioventricular nodal reentry tachycardia
- atrioventricular node
- congenital heart disease ◼ supraventricular tachycardia
- transposition of great vessels
A 19-year-old male with congenitally corrected transposition of the great arteries (ccTGA; S, L, L–situs solitus, l-loop, l-transposition)1,2 presented with recurrent frequent palpitations, fatigue, and effort intolerance. Previous history was significant for initial presentation with supraventricular tachycardia (SVT) at the age of 14 years. Transthoracic echocardiography at that time led to diagnosis of ccTGA. He reportedly underwent a posteroseptal accessory pathway ablation, and subsequently a second ablation the same year for recurrent SVT, again targeting a posteroseptal pathway. At the age of 17 years, he had a third procedure and reportedly linear ablation between the right atrioventricular valve (mitral), and inferior vena cava was performed for inducible right atrial flutter. Physical examination was unremarkable except for loud aortic closure on cardiac auscultation. The baseline ECG showed the presence of septal Q waves and the absence of lateral Q waves, findings characteristic of ccTGA (Figure 1A).1 The chest radiograph showed mesocardia without cardiomegaly or pulmonary congestion. Transthoracic echocardiography showed ccTGA, no atrial or ventricular septal defect, no pulmonary stenosis, normally functioning competent atrioventricular valves, and preserved function of both ventricles. Ambulatory monitoring revealed tachycardia, sometimes regular but at other times with an alternating variation in QRS axis and RR interval (Figure 1B). He was brought to the electrophysiology laboratory, and catheters were positioned in standard positions, including high right atrium, His-bundle, subpulmonic ventricle, and coronary sinus (CS). Dissociated signals were noted in the posteroseptal region/CS ostium, presumably related to previous ablations. With premature atrial beats, a distinctly different QRS complex with loss of notching in the inferior leads and a slightly more superior axis was noted. This second more superiorly directed QRS morphology was associated with a shortening in the recorded HV interval. There was no VA conduction. SVT was easily inducible with atrial extrastimuli and …