Left atrial thickness under the catheter ablation lines in patients with paroxysmal atrial fibrillation: insights from 64-slice multidetector computed tomography

Abstract

A detailed understanding of the left atrial (LA) anatomy in patients with atrial fibrillation (AF) would improve the safety and efficacy of the radiofrequency catheter ablation. The objective of this study was to examine the myocardial thickness under the lines of the circumferential pulmonary vein isolation (CPVI) using 64-slice multidetector computed tomography (MDCT). Fifty-four consecutive symptomatic drug-refractory paroxysmal AF patients (45 men, age 61 ± 12 years) who underwent a primary CPVI guided by a three-dimensional electroanatomic mapping system (Carto XP; Biosense-Webster, Diamond Bar, CA, USA) with CT integration (Cartomerge; Biosense-Webster) were enrolled. Using MDCT, we examined the myocardial thickness of the LA and pulmonary vein (PV) regions in all patients. An analysis of the measurements by the MDCT revealed that the LA wall was thickest in the left lateral ridge (LLR; 4.42 ± 1.28 mm) and thinnest in the left inferior pulmonary vein wall (1.68 ± 0.27 mm). On the other hand, the thickness of the posterior wall in the cases with contact between the esophagus and left PV antrum was 1.79 ± 0.22 mm (n = 30). After the primary CPVI, the freedom from AF without any drugs during a 1-year follow-up period was 78 % (n = 42). According to the multivariate analysis, the thickness of the LLR was an independent positive predictor of an AF recurrence (P = 0.041). The structure of the left atrium and PVs exhibited a variety of myocardial thicknesses in the different regions. Of those, only the measurement of the LLR thickness was associated with an AF recurrence.

Cardiovascular Magnetic Resonance Imaging of Scar Development Following Pulmonary Vein Isolation: A Prospective Study

“…Yokokawa et al found an increase in LA roof thickness of 1–2 mm [24]. While our baseline measured wall thickness of 7 mm is greater than that reported by CT imaging (1–4 mm) [38], [39]. This is likely due to 5 mm slice thickness which could cause partial-voluming of the LA wall with other tissues, or increased apparent thickness due to the LA wall curvature.…”

Results of catheter ablation of atrial fibrillation in hypertrophied hearts – Comparison between primary and secondary hypertrophy

“…Atrial stretch shortens the effective refractory period, increases the dispersion of the atrial effective refractory period, and potentiates the activity of ectopic triggers [21][22][23]. (2) The thickness of the left atrium exhibits a great variation between regions within the left atrium and among different patients [24]. Atrial tissue in hearts with LVH may differ from atrial tissue in hearts without LVH.…”

State-of-the-Art CT Imaging of the Left Atrium

“…4). A number of CT studies have identified differences in the thickness of the atrial wall between patients with conditions that elevate the atrial pressure [65][66][67]. A dependence of the atrial wall thickness on the presence of atrial fibrillation has also been demonstrated, and among patients undergoing catheter ablation procedures, local atrial electrophysiological phenomena have been localized to regions of greater wall thickness [68][69][70].…”