The Finding of Posterior Wall Low-Voltage Zones During Cryoballoon Pulmonary Vein Isolation Facilitated by Periprocedural Electroanatomical Mapping Predicts a Worse Ablation Outcome

Background: The presence of left atrial fibrosis indicates advanced remodeling and is associated with a worse outcome after pulmonary vein isolation (PVI). Conventional fluoroscopy-only cryoballoon ablation (CBA) lacks this prognostic information. The addition of electroanatomical mapping (EAM) using the inner lumen spiral catheter allows accurate voltage assessment of the left atrial posterior wall. However, the value of the finding of posterior wall low-voltage zones (pwLVZ) is unknown. Purpose: To study the value of left atrial voltage maps during CBA by comparing clinical and procedural characteristics and clinical outcome between patients with and without pwLVZ. Methods: A cohort of 250 consecutive patients who underwent index CBA for atrial fibrillation was analyzed. All patients underwent pre- and post-procedural EAM using the AchieveTM catheter and EnSiteTM mapping system. The presence of LVZ was evaluated at the postprocedural voltage map of the posterior wall. Clinical success was defined as freedom of documented AF or atrial tachycardia (AT) >30s after 1 year. Results: PwLVZ was found in 41/250 (16.4%) of patients. Patients with pwLVZ were older (69.3±8.5 vs 64.2±10.4; P=0.003), more frequent female (63.4% vs 32.5%; P< 0.001) and had higher CHA2DS2-VASc scores (3.0±1.6 vs 2.0±1.5; P< 0.001). The incidence of obesity (31.7% vs 25.8%; P=0.048), structural heart disease (35.5% vs 17.4%; P=0.021) and persistent AF (68.3% vs 43.8%; P=0.004) was higher in the pwLVZ group. Kaplan-Meier analysis of clinical outcome showed a higher recurrence rate in the pwLVZ group. The finding of pwLVZ was a predictor of atrial arrhythmia recurrence during follow-up (HR 2.583; 95%CI: 1.334-5.002; P=0.005). Conclusions: In CBA facilitated by integrated EAM, pwLVZ was associated with older age, female sex, higher CHADS-VASc scores, obesity, structural heart disease and persistent AF. The finding of pwLVZ is predictive of a worse clinical outcome.