Background: Atrial fibrillation (AF) causes structural and electrical remodeling, including atrial enlargement and fibrosis. Left atrial (LA) volume is a robust predictor for recurrence of AF after pulmonary vein isolation, however, recurrence of AF can be associated with multiple factors. Therefore, our objective was to test the hypothesis that comprehensive assessment of left atrium is better than the assessment of LA volume alone for predicting recurrence of AF.
Methods: We studied 104 patients with paroxysmal non-valvular AF who underwent pulmonary vein isolation. (age: 60±12 years, female: 34%). Transthoracic echocardiography was performed within two days before pulmonary vein isolation. Maximum (Max-LAVi) and minimum LA volume index (Min-LAVi) was calculated with the biplane modified Simpson’s method, and then normalized to the body surface area. On the basis of previous findings, the pre-defined cutoff of Max-LAVi for recurrence of AF was set at a Max-LAVi≥34mL/m2. Emptying LA volume index (Emptying-LAVi), a measure of reservoir function, was also calculated as Max-LAVi - Min-LAVi. Follow-up period after pulmonary vein isolation was 2 years.
Results: Recurrence of AF was observed in 23 patients (22%). As expected, multivariate logistic regression analysis showed that Max-LAVi was the only independent predictors of recurrence of AF (OR: 1.08; 95% CI 1.04-1.12; p< 0.001). It was noteworthy that sequential logistic regression models revealed that a model based on clinical variables including age, gender, duration of AF (χ2=3.7) was improved by addition of Max-LAVi (χ2=14.7; p<0.001), and further improved by addition of Emptying-LAVi (χ2=19.8; p=0.02).
Conclusion: Emptying LA volume was found to be associated with recurrence of AF, and may be a valuable additional factor for predicting recurrence of AF. Thus, the combined assessment of LA volume and emptying LA volume is easy-to-use, and may well result in better clinical management of AF patients.