Successful ablation of a superior fast-slow atrioventricular reentrant tachycardia in a patient with congenitally corrected transposition of great arteries

Figure 1. The electrocardiogram during sinus rhythm and supraventricular tachycardia. A: Sinus rhythm with a right bundle branch block morphology, left axis deviation, and no evidence of pre-excitation. B: During palpitations, a regular tachycardia (140 beats/min) was observed with the same QRS morphology as sinus. Retrograde P wave was observed during tachycardia (shown by red arrowheads).

Figure 2. The stimulus-His mapping and atrial activation mapping during right ventricular pacing. A: Stimulus-His mapping. The interval between the stimulus and the onset of the largest His potential deflection (St-H interval) was measured. The antegrade fast pathway was defined as the site with the minimum St-H interval (light purple is the shortest and red is longest St-H interval). B: Atrial activation mapping during right ventricular pacing. Left panel shows the earliest atrial activation site (red arrows) during right ventricular pacing. Right panel shows the earliest activation potential mapped by decapolar catheter. LAO = left anterior oblique; LAT = local activation time; RAO = right anterior oblique; RV = right ventricle.

Figure 3. The electrogram recording and catheter position at successful ablation site. A: Successful ablation site. The local electrogram recorded at ablation catheter (ABL) preceded the atrial potential of His by 12 ms. B: Catheter position of successful site and systemic ventricular atrium angiography. The distance between His bundle and the earliest atrial activation site during right ventricle (RV) pacing was 11.5 mm. C: Junctional beats appeared during catheter ablation. CS = coronary sinus; HRA = high right atrium; LAO = left anterior oblique; RAO = right anterior oblique; SVC = superior vena cava; TV = tricuspid valve.

Supplementary Figure 1. Cardiac computed tomography (CT) revealed congenitally corrected transposition of the great arteries (ccTGA: {I, D, D}-situs inversus, D-loop, D-transposition) undergoing combined Senning and Rastelli procedure. Ao: aorta, LV: left ventricle, PA: pulmonary artery, PVA: pulmonary venous atrium, RV: right ventricle, SVC: superior vena cava, SVA: systemic venous atrium, VSD: ventricular septal defect

Supplementary Figure 2. The earliest atrial activation mapping and electrogram recording during right ventricular pacing. (A) Retrograde conduction of the fast pathway was demonstrated after administration of isoproterenol (B) Electrogram recording during right ventricular pacing. AP: anteroposterior, CS: coronary sinus, HRA: high right atrium, RV: right ventricle