Predictive value of left atrial volume measured by non-invasive cardiac imaging in the treatment of paroxysmal atrial fibrillation.

PURPOSE

We investigate the role of left atrial volume (LAV) as a predictor of outcome following pulmonary vein isolation (PVI) in patients with exclusive paroxysmal atrial fibrillation (AF).

METHODS

PVI was performed in 213 patients (80 females, aged 60 ± 10 years) with paroxysmal AF using either the pulmonary vein ablation catheter (PVAC, n = 78) or conventional single-tip ablation (n = 135). LAV was assessed by multi-detector computed tomography (n = 39) or cardiac magnetic resonance imaging (n = 174) prior to ablation. LA diameter (LAD) and LA area were determined by echocardiography. Patients were followed up for 12 months clinically and with 72-h Holter ECG.

RESULTS

The mean LAV was 85 ± 28 ml (range, 22-189 ml). Mean LAD and mean LA area were 43 ± 6 mm and 23 ± 6 cm². After a follow-up period of 18 ± 5 months, 202 patients were analyzed. AF recurrence was documented in 50 (23%) patients. Univariate analysis showed age (59 ± 11 vs. 65 ± 6 years, p = 0.049), LA area (23 ± 5 vs. 27 ± 6 cm², p = 0.03), and LAV (80 ± 27 vs. 96 ± 28 ml, p = 0.04) to be significantly associated with the outcome. Multivariate analysis revealed that none of these parameters were statistically significant (hazards ratio LAV, 0.52-1.12, p = 0.058; LA area, 0.63-1.14, p = 0.069; and age, 0.90-1.09, p = 0.41). In the case of AF recurrence, patients with LAV >95 ml showed a significantly higher probability for the occurrence of persistent AF (24% vs. 8%, p = 0.02).

CONCLUSIONS

The assessment of LA size should not be incorporated as a main factor with regard to predicted ablation success in patients with paroxysmal AF being considered for PVI, as PVI may be successful even with considerable LA enlargement. Ablation should be performed promptly in patients with LAV ≤ 95 ml to prevent further LA dilatation, as patients with LAV >95 ml have an increased probability to develop persistent AF in the case of ablation failure.