In view the adverse consequence of AF “chronic or paroxysmal” comprising hemodynamic deterioration, risk of thromboembolic complications beside the intolerable fast palpitation, cardioverting AF to sinus rhythm is an ideal goal. There had been some controversy concerning the effect of AF on atrial dimensions and functions. Furthermore the need for long term warfarin anticoagulation prior to cardioversion is still on doubt. The present work addresses the latter 2 issues through studying 54 patients (27 females and 27 males, mean age 54 years, aged from 28 to 73 years. Underlying cardiac examination revealed rheumatic heart disease in 23 pts, hypertension in 19 pts, ischemic heart disease in 7 pts, lone AF in 3 pts only one pt had cardiomyopathy,and one pt had thyrotoxicosis. Prior to cardioversion all patients were subjected to clinical evaluation, transthoracic (TTE), transesophageal echocardiography were done only in 7 cases (TEE) and heparin or warfarin anticoagulation for at least 7 days, Standard M-Mode cross sectional and pulsed Doppler echocardiography were obtained using Hewlett-Packard Sonos 72720. Echo parameters measured before cardioversion compared LVEDD, LVESD, FS, left atrial dimensions (length, diameter and volume by planimetry). Left atrial function after cardioversion expressed as atrial ejection force (AEF), mitral orifice by planimetry, Doppler E-wave before cardioversion and E/A ratio after cardioversion, the presence of LA thrombus or spontaneous echo contrast (SEC) were studied by TTE or TEE. Measures were recorded 2 weeks after cardioversion to avoid LA stunning. Restoring sinus rhythm result in significant reduction of left atrial length (5.1 versus 6.2, p<0.001), left atrial diameter (3.96 versus 4.11, p<0.0001), left atrial volume (50 versus 57, p<0.0001), there was also significant recovery of atrial function found in all patients successfully reverted to sinus rhythm (42 patients), however A-wave 0.5 m/s (EMAF) was found in 17/42 (40%) pts successfully cardioverted after 2 weeks, while after 3 months 17/21 pts (81%) remained in sinus rhythm had A-wave 0.5 m/s.. On the other hand left ventricular function showed compensatory changes in pre to post-cardioversion status LVEDD (5.19 versus 5.35, p0.0001), LVESD (3.35 versus 3.67, p0.0001), FS (36 versus 33, p0.001). In conclusion respectively the argument of rate versus rhythm control in AF would favor maintaining sinus rhythm in the view of echo parameters showing regression of cardiac function following cardioversion with expected favorable effect lessening the chances of blood stasis and chances for LA thrombosis.