Author + information
- Received March 24, 1987
- Revision received July 27, 1987
- Accepted September 24, 1987
- Published online February 1, 1988.
- Dominique De Zuttere, MD∗,a,b,
- Thierry Touche, MDa,b,
- Georges Saumon, MDa,b,
- Alain Nitenberg, MDa,b and
- Richard Prasquier, MDa,b
- ↵∗Address for reprints: Dominique de Zuttere, MD, Service d'Explorations Fonctionnelles, Hôpital Bichat, 46 rue Henri Huchard, 75018 Paris, France.
Instantaneous intracardiac flow volumes can be calculated as the product of instantaneous flow velocity and instantaneous orifice area. This was accounted for in a new method of measuring stroke volume and cardiac output in the mitral orifice by pulsed Doppler echocardiography. This method was compared with simultaneous thermodilution in 30 adult patients in sinus rhythm without substantial atrioventricular or pulmonary valve abnormalities. The mitral orifice was assimilated to a conduit with 1) an ellipse-shaped inlet and outlet, 2) the same (and constant) long axis tor the inlet and outlet ellipses (that is, the mediolateral anulus diameter measured on apical four chamber views), and 3) a varying outlet short axis (that is, the mitral anteropostprior leaflet separation derived from left parasternal M-mode recordings). This method design avoided the need for a short-axis, view of the whole circumference of the mitral outlet orifice, which is difficult to obtain in many adult patients.
The mitral flow velocity was recorded from the apex under two-dimensional guidance, within the mitral canal, close to the outlet section. Integration of instantaneous mitral leaflet separation multiplied by instantaneous flow velocity was performed using Simpson's rule.
In addition to the proposed “instantaneous orifice area” method (method A), a “mean orifice area” method (method B) was also compared with thermodilution. In this simplified method, mitral flow was the product of mean orifice area and the diastolic mitral velocity integral, both derived from the same recordings as for method A. Close correlations were observed between thermodilution and Doppler flow measurements with method A, both for stroke volume (r = 0.94, SEE = 7.3 ml) and cardiac output (r = 0.91, SEE = 0.53 liter/min). Flow values were underestimated by method B, which appeared less well correlated with thermodilution (r = 0.82, SEE = 10.3 ml for stroke volume; r = 0.82, SEE = 0.78 liter/min for cardiac output).
It is concluded that the proposed instantaneous velocity-area method, validated by simultaneous thermodilution in adult patients, provides a reliable and clinically feasible approach to noninvasive flow quantitation within the mitral orifice.
☆ This study was supported by grants from INSERM, CNAMTS, Université Paris 7 and Fondation pour la Recherche Médicale, Paris, France.
- Received March 24, 1987.
- Revision received July 27, 1987.
- Accepted September 24, 1987.