Recovery Of Atrial Mechanical Function After Cardioversion Of Atrial Fibrillation: Assessment By Tissue Doppler Imaging,M-mode And Pulsed Doppler Echocardiography

Background: Atrial fibrillation is a common arrhythmia, occurring in 0.4% of the general population and in up to 4% of people >60 years of age. The electrical or pharmacological cardioversion is generally performed to improve cardiac function, relieve symptoms and decrease the incidence of thrombus formation. But recovery of atrial mechanical motion may be delayed for several weeks after successful cardioversion of atrial fibrillation to sinus rhythm. The lack of effective mechanical atrial function after cardioversion predisposes patients to thromboembolic complications.Objective: This study evaluated the recovery of atrial function after successful cardioversion in patients with atrial fibrillation, utilizing tissue Doppler imaging and M-mode echocardiography in atria-ventricular annulus motion, together with pulsed Doppler echocardiography and apexcardiogram.Methods: This study consisted of 34 patients with atrial fibrillation who successfully underwent electrical or pharmacological cardioversion in our hospital. Twenty age-matched healthy individuals in sinus rhythm served as controls. Patients with atrial fibrillation of short duration ( 4weeks, 18 patients) or long duration (>4weeks,16 patients) were followed up in 1 hour, 1 day, 1 week and 1 month after successful cardioversion. From the echocardiography apical 4-chamber views, the atrial mechnical activities in the mitral and tricuspid annulus were recorded using 2-dimentional guided M-mode and tissue Dopple imaging. Furthermore, pulsed Doppler transmitral and transtricuspid inflow velocity and apexcardiogram were also recorded. Atrial stunning means the lack of atrial mechanical function after atrial electrical activity was recovered with successful cardioversion.Results: The incidence of atrial stunning occurred in left or right atrium about 20.6% and 14.7% respectively. The atrial mechanical function fully recovered in left atrium around 1 month after cardioversion and in right atrium around 1 week. Left atrial mechanical function improved greater in 1 hour, 1 day and 1 week after cardioversion in patients of short duration than the long duration, In both groups, left atrial mechanical function increased over time, ultimately achieving similar levels. Full recovery of atrial mechanical function, however, was achieved within 1 week in patients of short duration and within 1 month in patients of long duration.Conclusion: Atrial stunning can happen In both atria. The recovery of left atrial mechanical function is slower than the right atrium. Recovery of left atrial mechanical function is related to the duration of atrial fibrillation before cardioversion.