Left Atrial Sphericity Index Predicts Early Recurrence of Atrial Fibrillation After Direct-Current Cardioversion: An Echocardiographic Study

BACKGROUNDAttempts to achieve rhythm control using direct-current cardioversion (DCC) are common in those with persistent atrial fibrillation (AF). Although often successful, AF recurs within 1 month in as many as 57% of patients. The aim of this study was to assess whether a baseline left atrial sphericity index (LASI) acquired by 2-dimensional transthoracic echocardiography (TTE) could be used as a predictor of AF recurrence after successful DCC. HypothesisA baselline LASI assessed by 2D TTE can predict AF recurrence after successful DCC in patients with persistent AF. MethodsA total of 124 consecutive patients with persistent AF lasting <120 days underwent successful DCC. Other than -blockers, no other antiarrhythmic treatment was administered. Prior to DCC, all patients underwent thorough TTE, and LASI was calculated as the fraction of the left atrial width/length of the largest possible left atrial volume in a 4-chamber view. The primary outcome was a TTE-estimated baseline LASI as a predictor of AF recurrence after successful DCC for persistent AF. ResultsAnatomically, a more spherical shape of the left atrium (LASI >0.9) proved to be a strong and independent predictor of AF recurrence, with an odds ratio between 4.1 (95% confidence interval: 1.6-11.9, P = 0.005) and 7.6 (95% confidence interval: 3.3-19.7; P = 7.2x10(-6)). The receiver operating characteristic curve indicated good power for distinguishing between recurring and nonrecurring AF, and we chose a cutoff of 0.9 because high specificity was a priority for clinical reasons. ConclusionsIn conclusion, baseline LASI >0.9 was associated with significantly greater AF recurrence throughout the 12-month follow-up period.