Assessing the Efficacy of Cryoballoon Ablation
A 62-year-old man with a history of highly symptomatic paroxysmal atrial fibrillation (AF) refractory to multiple antiarrhythmic drugs was referred for catheter ablation.
Pulmonary vein isolation (PVI) was performed using a 28-mm cryoballoon (CB; Arctic Front©, Medtronic CryoCath LP; Pointe-Claire, Québec) with the guidance of a small calibre 20-mm diameter circular mapping catheter (CMC) introduced into the central lumen of the CB catheter.
Shown in Figure 1 is the CB catheter, which is positioned at the ostium of the left superior pulmonary vein (LSPV). A 20 mm CMC is positioned inside the LSPV to ensure catheter stability and optimize PV ostium-cryoballoon contact. Despite the persistence of a small leak detected during pre-ablation contrast injection (Figure 1) cryoballoon ablation was initiated.
Approximately 90 seconds after the initiation of cryoballoon ablation a delay in left atrial-PV conduction was observed (*) followed by persistent LA-PV (entrance) conduction block (Figure 2). Cryoablation was continued for a standard four-minute cycle after which entrance and exit block was verified. Figure 3 demonstrates the cryoballoon temperature curve during the cryoballoon application.
With respect to this PV, what would you do next?