Effect of left atrial size on recurrence of atrial fibrillation after electrical cardioversion: atrial dimension versus volume.

Unlabelled: There are conflicting reports on the relationship between left atrial dimension (LAD) determined by echo-cardiography and the incidence of atrial fibrillation (AF) recurrence after electrical cardioversion (EC). We hypothesized that left atrial volume (LAV) by echocardiography might better differentiate patients who will have recurrence of AF after EC.

Methods: Forty-one patients having EC for AF were prospectively studied by echocardiography. LAD was measured by American Society of Echocardiography guidelines as the anterior-posterior dimension in the parasternal view. LAV was measured by Simpson's method using an off-line analysis system and reported as the average of values from the apical four-chamber and two-chamber views.

Results: (Data are mean +/- SEM): Patient follow-up was 15 +/- 10 months. No cutoff value of LAV predicted AF recurrence, but all three patients with LAD greater than 65 mm had AF recurrence. Compared with patients maintaining normal sinus rhythm (NSR) (N = 18), the AF group (N = 23) had a lower percentage of antiarrhythmic drug use, especially type IA agents (p < .02). Patients who stayed in NSR tended to have shorter AF duration before EC (16 +/- 15 v 63 +/- 122 weeks, p = .08) but did not differ in age (53 +/- 27 v 58 +/- 23 years), LAD (51.1 +/- 7.7 v 54.2 +/- 9.4 mm) or LAV (85.1 +/- 24.3 v 95.1 +/- 33.3 mL).

Conclusions: (1) LAV by echocardiography does not improve identification of patients at risk for recurrence of AF after EC, (2) patients with LAD up to 65 mm may maintain NSR after EC, (3) LAD greater than 65 mm is associated with AF recurrence, and (4) use of antiarrhythmic drugs and the duration of AF before EC may be better predictors of maintenance of NSR than echocardiographic measures of left atrial parameters.