Left atrial wall thickness in paroxysmal atrial fibrillation by multislice-CT is initial marker of structural remodeling and predictor of transition from paroxysmal to chronic form.

PURPOSE

We used ECG-gated MSCT to evaluate alterations in the LA wall in patients with paroxysmal atrial fibrillation (AF) (PAF) and compared with chronic AF (CAF) and normal sinus rhythm (NSR).

MATERIALS AND METHODS

We enrolled 3 groups, each consisting of 62 patients with either recurrent PAF (48 males, 65 ± 11 years), CAF (43 males, 69 ± 9 years), or NSR without any history of AF (40 males, 64 ± 11 years) for a total of 186 study patients. In CT, the absolute LA wall thickness (LAT) and LA volumes were calculated.

RESULTS

In CT, patients with PAF had significantly thicker LAT than those with either CAF or NSR (2.4 ± 0.2mm in PAF >2.1 ± 0.2mm in CAF or 1.9 ± 0.2mm in NSR, p<0.01). Patients with CAF had significantly larger LA volume than those with either PAF or NSR (p<0.01). Subsequently, 9 of the 62 patients with PAF developed CAF over a mean follow-up period of 19 ± 22 months. The mean LAT was significantly thinner in patients who had transitioned from PAF to CAF than in those who had not (2.2 ± 0.2mm and 2.4 ± 0.2mm, respectively) (p<0.01). Receiver operating characteristic analysis demonstrated that the area under the curve for LAT was greater than that for LA volume in CT and LAD in transthoracic echocardiogram. In the Kaplan-Meier analysis, the transition from PAF to CAF was observed more frequently in patients with LAT<2.4mm than LAT ≥ 2.4mm (p=0.018).

CONCLUSIONS

Alteration of the LA wall may suggest a part of structural remodeling in AF before the occurrence of LA dilatation. LAT in CT seems to be a useful predictor of the transition from PAF to CAF in patients with PAF.