Atypical inferoseptal accessory pathway connection associated with an aneurysm of the coronary sinus: Insight from a three-dimensional combined image of electroanatomic mapping and computed tomography

Figures

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  Figure 1. Twelve-lead surface electrocardiogram recorded during sinus rhythm before (A) and after (B) ablation.

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  Figure 2. A: Volume-rendered image reconstructed using cardiac computed tomography showing the location of the coronary sinus. B–D: Images of the epicardial adipose tissue surrounding both atrioventricular (AV) junctions and the inferior pyramidal space (black-dotted line) were reconstructed. When viewed from the anterosuperior direction, the transparency of the cardiac volume was increased (C) and the volume data of the AV epicardial adipose tissue along with the coronary venous system could be obtained (D), which were integrated with the electroanatomic mapping (see Figure 3). The coronary sinus (CS) was located on the left atrial side of the left AV junction (A). The CS aneurysm originated from the bifurcation of the inferior interventricular vein (IIV) and small cardiac vein (SCV), and was located just beneath the basal inferior left ventricle in contact with mitral valve annulus (MVA) at its neck (D). Red arrow in D indicates the estimated site of the accessory pathway. E, F: Fluoroscopy-like volume-rendered images were reconstructed to guide the procedure using cardiac computed tomography, as shown from the 30° right anterior oblique (E) and 45° left anterior oblique (F) views. Note…

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  Figure 3. A, B: Earliest atrial activation site assessed by the NavX system integrated with three-dimensional (3D) computed tomography (CT) in the left anterior oblique (A) and slightly cranial (B) views. C: Earliest ventricular activation site assessed by the NavX system integrated with 3D CT. Whereas a distinctive accessory pathway potential could be recorded at the neck of the coronary sinus (CS) aneurysm, the local ventricular activation was earlier deep within the aneurysm, where the unipolar electrogram confirmed a continuous P-QS morphology. The earliest ventricular activation likely spread toward the right inferoseptal wall near the tricuspid annulus but not the left ventricle (black arrow). The right and left panels show the local electrograms and surface electrocardiogram. The dotted line indicates the onset of the delta wave. D, E: CS venograms shown from the right anterior oblique (RAO) 30° (D) and left anterior oblique (LAO) 45° (E) views. White arrows indicate the CS aneurysm. F, G: Successful ablation catheter position shown in the RAO 30° (F) and LAO 45° (G) views. Of note, the successful ablation site was at the neck of the CS aneurysm, where a distinctive accessory…