Atrial 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.
A 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 h, 1, 2, 3, 4 weeks and 3 months after ECV. Mechanical recovery was defined as the achievement of a GSA+ value of 21%.
Independent 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 = 0.015) and maximal velocity left atrial appendage (P = 0.022). Female sex (P = 0.038), N-terminal pro-B type natriuretic peptide (P = 0.013), E/e′ (P = 0.042) and the indexed left atrium volume (P = 0.019) were associated with the lack of left atrium mechanical recovery.
In 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.
aDepartment of Cardiology, Ospedale San Giuseppe MultiMedica
bDepartment of Medicine and Surgery, University of Milano-Bicocca, Milano
cNephrology Unit, San Gerardo Hospital, Monza
dCardiovascular Department, MultiMedica IRCCS, Milano, Italy
Correspondence to Antonio Vincenti, MD, FESC, Ospedale San Giuseppe Multimedica IRCCS, Via San Vittore 12, 20123 Milano, Italy Tel: +39 330237357; e-mail: email@example.com
Received 22 May, 2019
Revised 8 August, 2019
Accepted 8 August, 2019