Left Atrial Functions in Rheumatic Chronic Mitral Regurgitation

Left Atrial Functions in Rheumatic Chronic Mitral Regurgitation Left atrial (LA) functions are affected in several cardiac pathologies. This study was planned to assess left atrial mechanical function in patients with rheumatic chronic mitral regurgitation (MR).18 patients (mean age 43 ±16 years) with isolated MR in sinus rhythm and 18 healthy controls (mean age 33 ±6 years) were included in this study. The severity of MR was estimated by color Doppler echocardiography. The ratio of MR jet area to left atrial area was calculated. With this method a ratio less than 0.20 was registered as mild, 0.20-0.39 as moderate, and 0.40 or greater as severe MR. LA volumes were measured echocardiographically at the time of mitral valve opening (LAVmax), at the onset of atrial systole (p wave on electrocardiography = LAVp) and at the mitral valve closure (LAVmin) according to the biplane area-length method in apical 4-chamber and 2-chamber view. All volumes corrected for body surface area, and following LA emptying functions were calculated. LA passive emptying volume (LAPEV)= LAVmax - LAVp, LA passive emptying fraction (LAPEF)= LAPEV/ LAVmax. Conduit volume (CV) =LV stroke volume-( LAVp- LAVmin), LA active emptying volume (LAAEV)= LAVp- LAVmin , LA active emptying fraction (LAAEF)= LAAEV/ LAVp , LA total emptying volume (LATEV)= (LAVmax -LAVmin), LA total emptying fraction (LATEF)= LATEV/LAmax. All measurements were averaged over three cardiac cycles.There were no significant differences in mean age, body surface area, and heart rate between patients and controls (p>0.05). Left ventricular end-diastolic and systolic diameters were significantly greater in patients with MR than in controls (p<0.001), whereas ejection fraction was not significantly different. A mean ratio of MR jet area to left atrial area were 0.37 ±10. LA dimension was significantly greater in patients with MR than in controls (p<0.001). LA volume indexes; Vmax, Vmin, and Vp were greater in patients with MR than in controls (p<0.001). Although LA passive emptying volume (p<0.01), LA active emptying volume (p<0.001), LA total emptying volume (p<0.001), conduit volume (p<0.005) were found significantly greater in patients with MR than in controls, LA passive emptying fraction (p<0.001), LA active emptying fraction (p<0.001), LA total emptying fraction (p<0.01) were significantly lower in patients with MR than in controls. The results of this study have indicated that LA maximal, minimal volumes and the one at onset of atrial systolie are increased, whereas LA mechanical functions are deteriorated in patients with rheumatic chronic MR