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Left ventricular flow propagation during early filling is related to wall relaxation: a color M-mode Doppler analysis
P Brun1, C Tribouilloy, A M Duval
1Unité de Recherche U. 2 de l'Institut National de la Santé et de la Recherche Médicale, Créteil, France.
Insights
The velocity of flow propagation, measured by color M-mode Doppler echocardiography, is a reliable indicator of left ventricular relaxation. This method can help assess diastolic function in various heart conditions.
Area of Science:
- Cardiovascular Imaging
- Diagnostic Echocardiography
- Cardiac Physiology
Background:
- Assessing left ventricular relaxation noninvasively is challenging.
- Existing methods are limited by the complex interplay of relaxation rate and filling pressures.
Purpose of the Study:
- To evaluate the relationship between flow propagation velocity and left ventricular relaxation.
- To assess the utility of color M-mode Doppler echocardiography in analyzing left ventricular diastolic function.
Main Methods:
- Color M-mode Doppler echocardiography was used to measure flow propagation velocity during early filling.
- Data were compared with conventional pulsed Doppler.
- Studies included normal subjects and patients with various cardiomyopathies and valvular diseases.
Main Results:
- Color M-mode and pulsed Doppler data showed high correlation.
- Flow propagation velocity was significantly lower in patients with altered relaxation compared to normal subjects.
- Velocity correlated inversely with the isovolumetric relaxation time constant.
Conclusions:
- Flow propagation velocity is highly dependent on left ventricular relaxation rate.
- This parameter serves as a valuable tool for studying diastolic function.
- Color M-mode Doppler echocardiography offers a promising approach for noninvasive assessment of diastolic function.
Objectives:
This study was designed to evaluate the relation between the velocity of flow propagation and left ventricular relaxation by using color M-mode Doppler echocardiography to analyze flow propagation in the left ventricle.
Background:
Noninvasive attempts to identify alterations in left ventricular relaxation have been hampered because both the relaxation rate and left atrial filling pressure are the determinants of peak early velocity and filling rate.
Methods:
Color M-mode velocity data were transferred to a microcomputer and compared with conventional pulsed Doppler data to assess the ability of color M-mode echocardiography to analyze velocity field properties. The velocity of flow propagation was measured as the slope of the flow wave front during early filling in normal subjects (n = 29) and in patients with disease that alters relaxation (dilated cardiomyopathy [n = 31], ischemic cardiomyopathy [n = 8], hypertrophic cardiomyopathy [n = 5], systemic hypertension [n = 22] and aortic valve disease [n = 25]). In nine patients with end-stage dilated cardiomyopathy, echocardiographic and left heart catheterization data were obtained at baseline and during intracoronary dobutamine infusion.
Results:
Color M-mode and pulsed Doppler echocardiographic data were highly correlated (n = 217, r = 0.94, p less than 0.0001, velocity range 0.2 to 1.5 m/s). The velocity of flow propagation was lower in patients than in normal subjects (0.46 +/- 0.15 vs. 0.84 +/- 0.11 m/s, p less than 0.0001). The decrease was significant in all disease forms with or without left ventricular dilation. The velocity of flow propagation was related to peak early velocity in normal subjects (p less than 0.001) but not in patients. It varied inversely with the isovolumetric relaxation time constant during dobutamine infusion and the two variables were highly correlated (p less than 0.0001).
Conclusions:
The velocity of flow propagation during early filling seems to be highly dependent on the left ventricular relaxation rate and could be an important tool in studying diastolic function.