CRT Upgrade Procedures
Eight patients successfully underwent CRT upgrade procedures guided by an Inner-Cath alone without any complications. Of all 8 patients receiving CRT upgrade, 5 patients (62.5%) showed stenosis of the subclavian vein (4 patients) or both subclavian and brachiocephalic veins (1 patient) due to adhesions of pacemaker leads to the venous wall. Consequently, one of the 5 patients only required a dilation of the left subclavian vein for insertion of a 7Fr sheath into the stenotic vein. In another patient with left subclavian and brachiocephalic vein occlusions, a 7Fr sheath was successfully inserted through the occluded veins with angioplasty (Figure 4).