Mechanical atrial recovery after cardioversion in persistent atrial fibrillation evaluated by bidimensional speckle tracking echocardiography.

Abstract

BACKGROUND\nAtrial fibrillation induces reversible electrical and mechanical modifications (atrial remodeling). Atrial stunning is a mechanical dysfunction with preserved bioelectrical function, occurring after successful atrial fibrillation electrical cardioversion (ECV). Two-dimensional speckle tracking echocardiography is a new technology for evaluating atrial mechanical function. We assessed atrial mechanical function after ECV with serial two-dimensional speckle tracking echocardiography evaluations. The investigated outcome was left atrium mechanical recovery within 3 months.\n\n\nMETHODS\nA total of 36 patients [mean age 73 (7.9) years, 23 males] with persistent atrial fibrillation underwent conventional transthoracic and transesophageal echocardiography before ECV. Positive global atrial strain (GSA+) was assessed at 3\u200ah, 1, 2, 3, 4 weeks and 3 months after ECV. Mechanical recovery was defined as the achievement of a GSA+ value of 21%.\n\n\nRESULTS\nIndependent predictors of GSA+ immediately after ECV (basal GSA+) were E/e ratio and left atrial appendage anterograde flow velocity. During the follow-up, 25% of patients suffered atrial fibrillation recurrence. In 12/36 patients (33%) left atrium mechanical recovery was detected (mechanical recovery group), while in 15/36 (42%) recovery did not occur (no atrial mechanical recovery group). At univariate analysis, the variables associated with recovery, were basal GSA+ (P\u200a=\u200a0.015) and maximal velocity left atrial appendage (P\u200a=\u200a0.022). Female sex (P\u200a=\u200a0.038), N-terminal pro-B type natriuretic peptide (P\u200a=\u200a0.013), E/e (P\u200a=\u200a0.042) and the indexed left atrium volume (P\u200a=\u200a0.019) were associated with the lack of left atrium mechanical recovery.\n\n\nCONCLUSION\nIn almost half of the patients, the left atrium did not resume mechanical activity within the 3 months after ECV, despite sinus rhythm recovery. The left atrium of these patients was larger, stiffer and their E/E was higher, suggesting a higher endocavitary pressure compared with mechanical recovery patients. These findings might suggest an increased thromboembolic risk.