Figure 1. Cryoablation tools originally used for catheter ablation of AF. Panel A, shown, are a 6-mm and a 4-mm tip focal cryoablation catheter. Panel B, illustrates a curvilinear cryoablation catheter with a 64- mm freezing segment and the ability to expand to a diameter of 18 to 30 mm. This was the first cryoablation catheter specifically designed for PV isloation. Panel C, illustrates the ‘block the vein’ strategy – through this approach the PV is mechanically occluded using an angioplasty balloon catheter, advanced through the curvilinear cryoablation catheter to diminish PV blood flow and to further enhance the efficacy of cryoablation.