Introduction: Quantify longitudinal systolic function of the myocardium aft er spontaneous, chemical or electric conversion of atrial fibrillation Methods: Patient selection: atrial fibrillation, absence of conversion contraindications, excluded patients with permanent fi brillation, coronary syndrome, cardiomyopathy, conduction disorders, heart failure, valvular pathology. Th e echocardiographic parameters used were: left and right atrial volume, spectral and tisular mitral and tricuspidian fl ow, E/E’ ratio, displacement of mitral ring MAPSE and tricuspidian ring TAPSE, mitral and tricuspidian systolic tissue velocities, in patients and control group. Evaluations were performed before conversion and aft er one hour, 24 hours, 7 days and one month. Results: We evaluated 34 patients – 16 women and 18 men, 65 ± 5.7 years old, right atrial volume 39 ± 8 ml, left artial volume 54 ± 5 ml, mitral A wave at one hour 0.64 ± 0.09 m/s, tricuspidian A wave 0.43 ± 0.07, E/E’ ratio 13 ± 5. At one hour, resumption of mechanical activity of left atrium was 80% and right atrium 95%. Before conversion mitral tissular velocities were 0.09 ± 0.01, tricuspid tissular velocities 0.11 ± 0.05 and after one hour were 0.12 ± 0.06, respectively 0.14 ± 0.04, MAPSE were 12 ± 5 before conversion and 14 ± 3 aft er conversion, TAPSE before conversion 24 ± 6 and aft er conversion 25 ± 4. Conclusions: 1. Atrial mechanical function parameters were not diff erent in relation to the type of conversion; 2. Mitral A wave magnitude correlates with LA volume (positive regression coeffi cient); 3.Tricuspid A wave velocity were superior to the mitral wave compared to the study group, suggesting early resumption of RA function; 4.Tissular velocity aft er conversion increased at both rings; 5. The magnitude of mitral tissular velocity is correlated to LA size (negative regression coeffi cient); 6.Tricuspid systolic velocity was superior to the mitral systolic velocity compared to the control group, suggesting an upper longitudinal function to RV; 7. E/E’ ratio aft er conversion enroll in “the gray area”, suggesting increasing LV fi lling pressure.