APPLICATION OF THE FLOW CONVERGENCE REGION METHOD TO THE DETERMINATION OF STROKE VOLUME AND CARDIAC-OUTPUT IN PATIENTS WITH MITRAL-STENOSIS

OBJECTIVE: This study was undertaken to investigate the feasibility an d accuracy of determination of stroke volume and cardiac output by cal culating transmitral flow volume using the flow convergence region met hod in patients with mitral stenosis. PATIENTS AND INTERVENTIONS: Fift y-six patients with rheumatic mitral stenosis were studied using imagi ng and Doppler echocardiography. Aliasing velocities of 20 to 23 cm/s were used to record the flow convergence region proximal to the stenot ic mitral orifice. The stroke volume (mL) was calculated by multiplyin g peak transmitral flow rate which was obtained using an angle-correct ed hemispheric flow convergence equation, by transmitral velocity time integral (cm) divided by peak transmitral velocity (cm/s) recorded us ing continuous wave Doppler method. MAIN RESULTS: Stroke volume calcul ated using the flow convergence region method was not significantly di fferent from that calculated using aortic Doppler two-dimensional echo -cardiographic method in 39 patients with pure mitral stenosis (75+/-1 9) [mean+/-1SD] versus 73+/-19 mL, P=0.12), and from that calculated u sing pulmonic Doppler two-dimensional echocardiographic method in nine patients with mitral stenosis with associated >2+ aortic regurgitatio n (77+/-12 versus 75+/-14 mL, P=0.49). No significant difference exist ed between the cardiac output obtained using Fick method in 12 patient s with pure mitral stenosis. The stroke volume was overestimated by th e flow convergence region method when compared with those obtained usi ng aortic Doppler two-dimensional echocardiographic method in patients with mitral stenosis with associated >2+ mitral regurgitation (123+/- 40 versus 67+/-15 mL, P=0.001). CONCLUSIONS: The present study provide d an alternative way to calculate the stoke volume and cardiac output in patients with mitral stenosis.