Fig 4. a. Illustration of the RA showing the “horseshoe” arrangement of the SN complex in which this structure is situated both medial (“head”) and lateral (“tail”) to the mid-line of the SCV-RA junction at the AR. b. Histological image of a transversal section of the SVC-RA junction viewed from a cephalic view showing a “horseshoe” disposition of the SN complex with medial and lateral extensions along the AR. d. 3-D “in-situ” visualization of the human cardiac conduction system performed by means of advanced imaging tools of virtual CT dissection on human cadavers showing extension of the SN complex (in red) from the lateral to the septal SVC-RAA junction. Note the septal extension of the SN coming to the interatrial septum next to the Ao. d., e. 3-D activation map of the RA during high HR from RAO and anterosuperior views, respectively. Note the RF lesion set starting at the earliest activation (red ablation dots) at the AR and extended towards its septal portion (pink ablation dots) instead of going to the lateral SVC-RA junction that is relatively next to the PN (dark dots). RA: right atrium, SVC: Superior Vena Cava, IVC: Inferior Vena Cava, RAA: right atrial appendage, TV: Tricuspid valve, PN: Phrenic nerve, Ao: aorta, AVCA: Atrioventricular conduction system, RV: Right ventricle, LV: Left ventricle, PT: Pulmonary trunk. Reproduced from: Kawashima T, Sato F. First in situ 3D visualization of the human cardiac conduction system and its transformation associated with heart contour and inclination. Sci Rep. 2021;11(1):1–15; Anderson RH, Yen SH, Becker AE. The surgical anatomy of the conduction tissues. Thorax. 1983; 38:408–20; Anderson KR, Ho SY, Anderson2 RH. Location and vascular supply of sinus node in human heart. Br Heart J. 1979; 41:28–32.
Table 1.pre and post ablation heart rate variables in patients undergoing SNM in our cohort.