Sinus rhythm was restored in 102 patients with atrial fibrillation. Cardioversion was spontaneous (n=6), pharmacological (n=35), and electrical - early (n=46) or postponed because of necessity of full anticoagulation (n=15). Irrespective of method of cardioversion all patients had signs of atrial stunning. Doppler echocardiography performed within 24 hours and in 3, 7 and 14 days after cardioversion showed that rate of recovery of mechanical left atrial function had pronounced individual variations. In patients with spontaneous termination of atrial fibrillation normalization of left atrial contractile activity occurred in about 3 days, after pharmacological cardioversion - in 1 week (in 91.4% of cases). After early and postponed electrical cardioversion mechanical left atrial function recovered in 2 weeks in 97.8 and 73.3% of patients, respectively. Most important impact on this process produced duration of the last attack of atrial fibrillation and left atrial dimensions.