Left Atrial Low-Voltage Zone Assessment and Voltage-Guided Ablation Outcome in Patients With Atrial Fibrillation-Induced Tachycardiomyopathy

Abstract

Background: Persistent atrial fibrillation (AF) patients with tachycardia-induced cardiomyopathy (TIC) undergoing catheter ablation have similar or even better outcomes than patients without TIC. Data regarding atrial substrate remodeling are scarce in cases of TIC. We assessed regional distribution of left atrial (LA) bipolar voltage, the extent of low-voltage zones (LVZs), and outcomes of voltage-guided ablation in AF patients with and without TIC.

Methods and results: In all, 139 patients with persistent AF presenting for a first voltage-guided catheter ablation were enrolled, 61 with TIC and 78 with structurally normal hearts. LA voltage maps were obtained using a 3-dimensional electroanatomical mapping system in sinus rhythm. LVZ was defined as <0.5 mV. Compared with non-TIC patients, TIC patients had a lower indexed LA volume (median [interquartile range] 58.6 [50.6-68.7] vs. 63.4 [60.1-76.1] mL/m²; P<0.01) and higher LA voltage (2.3 [1.5-2.8] vs. 1.7 [1-2.6] mV; P=0.02). LVZs were less frequently found in patients with than without TIC (8 [13.1%] vs. 30 [39%]; P<0.01). There was no significant difference in atrial tachyarrhythmia (AT)-free survival rate over a 36-month follow-up between the 2 groups (log-rank test, P=0.176). No predictor of AT recurrence was identified.

Conclusions: TIC patients exhibit less LA substrate remodeling with a smaller LA volume, higher bipolar voltage, and fewer LVZs than non-TIC patients. They have a similar favorable outcome after a single procedure.

Keywords: Atrial fibrillation; Bipolar voltage map; Catheter ablation; Low-voltage zone; Tachycardia-induced cardiomyopathy.