Left ventricular wall thickening predicts left atrial low voltage areas in patients undergoing catheter ablation for atrial fibrillation

Abstract Background The success rate of circumferential pulmonary vein isolation (CPVI) remains suboptimal in patients with paroxysmal and persistent atrial fibrillation; moreover, the detection of low voltage areas (LVA) in the left atrium does predict an even higher recurrence rate of atrial tachyarrhythmias after the procedure. Left ventricular wall thickening (LVWT) is known to correlate with left atrial volume; however, no data is available whether LVWT is predictive of the presence of left atrial LVA. Purpose The aim of this study was to investigate whether LVWT is predictive of left atrial LVA and to verify that the presence of LVA confer a higher arrhythmia recurrence rate after catheter ablation for atrial fibrillation. Methods A total of 374 patients who undervent CPVI with the use of 3D electroanatomical mapping system as a primary procedure were enrolled in the study. Transthoracic echocardiography was performed in all patients prior the procedure with measurement of the thickness of the septum and the posterior wall. Patients were classified based on LVWT as normal (females:≤9mm, males:≤10mm), borderline (females:10-11mm, males: 11-12mm) and increased (females:≥12mm, males:≥13mm). A detailed left atrial voltage map was obtained in all patients prior to ablation with the identification of LVA (bipolar voltage <0.5mV with an area >5cm2). Arrhythmia recurrence was defined as documented atrial fibrillation or atrial tachycardia lasting for at least 30 seconds. Results Among 374 patients (mean age: 59.0±10.2 years, 131 females) 94, 195 and 85 were considered to be normal, borderline and increased based on LVWT, respectively. LVA were found in 29.9% (112/374) of patients. According to LVWT, LVA were detected in 16.0% (15/94), 31.3% (61/195) and 42.4% (36/85) in patients with normal, borderline and increased wall thickness, respectively, p=0.005. Patients with left atrial LVA had a higher [60.7% (68/112)] arrhythmia recurrence compared to those without low voltage areas [35.1% (92/262)] during a mean follow-up of 2.1±1.9 years, p<0.0001. Conclusions Left ventricular wall thickening predicts the presence of left atrial low voltage areas in patients undergoing catheter ablation for atrial fibrillation. Low voltage areas confer a higher arrhyhtmia recurrence rate during follow-up.