N. Horibe et al., APPLICATION OF THE FLOW CONVERGENCE REGION METHOD TO THE DETERMINATION OF STROKE VOLUME AND CARDIAC-OUTPUT IN PATIENTS WITH MITRAL-STENOSIS, Canadian journal of cardiology, 12(4), 1996, pp. 363-369
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.