Definition and outcome measures
The MS was defined as the thinnest part of the interventricular septum on the perpendicular annular plane image, and MS length was measured as the distance from the annular plane to the vertex of the muscular septum in stretched vessel image (18 ). Leaflet calcification and LVOT calcification severity were semi-quantitatively measured as previously defined (21, 22 ). The implantation depth was measured with fluoroscopy images by using institutional imaging software. The implantation depth was defined as the distance between the bottom of the non-coronary cusp (NCC) to the ventricular end of the valve stent frame in the final angiogram after the valve deployment (Figure 2 ). The angle of the image was normally perpendicular deployment view, but it can be adjusted by the attending physician.
To evaluate CD following TAVR, we set the primary endpoint as in-hospital new CD (new-onset LBBB or new PPI). The indication of PPI following TAVR was decided by the heart team at each hospital. Also, the hemodynamic outcome measured by ultrasound and in-hospital complications based on VARC-2 criteria (23 ) were collected. The preoperative risk was evaluated by calculating the Society of Thoracic Surgeons predicted risk of mortality (STS-PROM) score. The baseline characteristics, procedural characteristics, complications, and results were compared between the patients without CD and with CD following TAVR. Also, CD and hemodynamic results were compared between the 2 groups based on implantation depth and MS length (implantation depth > MS length and implantation depth ≤ MS length groups).