Definition of the location of DGCV-AIV origin
The DGCV-AIV origin of VAs was identified by mapping and ablation outcomes combined with retrograde venography of the coronary venous system. In our study, DGCV-AIV refers to the anatomy in the distal portion of the great cardiac vein, including four regions, DGCV1, DGCV2, summit-CV, AIV. DGCV1 is defined as the segment of DGCV at the epicardium of anterolateral wall of mitral annulus and DGCV2 as the segment of DGCV transecting the epicardial LV outflow region bounded by the bifurcation between the left anterior descending artery and left circumflex artery, and continued to DGCV1. Anterior interventricular vein (AIV) refers to the vein going along the anterior interventricular groove from cardiac apex to bottom, turning posteriorly and continuing as DGCV2. Summit-CV refers to the communicating vein (CV) between the aortic and pulmonary annulus, which is the extended tributary of the DGCV located distal to the origin of the AIV, see Figure2 .