Swartz sheath

After puncturing jugular and femoral veins, under the guidance of X-ray or intracardiac echocardiography, a decapolar catheter was inserted into the coronary sinus, and a single transseptal puncture was made with a Swartz sheath (Abbott, Chicago, USA). After the transseptal puncture, Heparin was given at a dose of 100 U/kg body weight, and it was given again to keep the activated clotting time between 300 and 350 s. Under the direction of an electro-anatomy mapping system (EAM; Biosense Webster, Irvine, USA), mapping and ablation were performed by experienced electrophysiological doctors, using a Pentaray mapping catheter (Biosense Webster, Irvine, USA) and Thermocool Smart touch SF catheter (Biosense Webster, Irvine, USA). Ablation points were marked automatically according to VisiTag (Biosense Webster, Irvine, USA) settings. (The size of the lesion tag was set at 2.5 mm, minimum time 3 s.) Throughout the process, the irrigation flow was 15 ml per minute and the radiofrequency (RF) power was set to 45 W.

EI-VOM was first performed. The coronary sinus was cannulated by a modified 6 F Judkins right guiding catheter (Judkins R4.0) inside the Swartz sheath (Abbott, Chicago, USA). CS venograms were performed to identify the presence of the VOM. If present, an over-the-wire angioplasty balloon (Emerge 1.5-2.5 mm x 6–8 mm; Boston Scientific) preloaded with guidewire was advanced into the proximal VOM. 5–8 ml 96% ethanol was injected into the VOM over 1 min. In addition, the ostium of VOM was marked on the reconstructed CS map. The conduction block was evaluated after completing PVI. If the endpoint was not achieved, step 2 was initiated. (Fig. 2)
Fig. 2

Ethanol infusion of the vein of Marshall (EI-VOM) and marked VOM ostium(red arrow)