Color M-mode flow propagation velocity and conventional doppler indices in the assessment of diastolic left
Antonio J Chamoun1, Tianrong Xie, Marti McCullough
1Division of Cardiology, University of Texas Medical Branch, Galveston, Texas 77555, USA.
Insights
Color M-mode flow propagation velocity (Vp) is an afterload-independent measure of diastolic function in cardiomyopathy patients. Conventional Doppler indices, however, are sensitive to afterload changes induced by isometric exercise.
Area of Science:
- Cardiology
- Echocardiography
- Diastolic Function
Background:
- Diastolic dysfunction is a key feature of cardiomyopathy.
- Assessing diastolic function can be challenging due to preload and afterload dependencies.
- Color M-mode flow propagation velocity (Vp) has emerged as a potential preload-independent index.
Purpose of the Study:
- To investigate the impact of increased afterload on diastolic function assessment in cardiomyopathy patients.
- To compare the afterload-dependency of Vp versus conventional Doppler indices during isometric handgrip exercise.
Main Methods:
- Twenty-four patients with systolic dysfunction were divided into two groups based on E/A ratio.
- Measurements of Vp, E velocity, deceleration time (DT), A velocity, isovolumic relaxation time (IVRT), and pulmonary atrial flow reversal velocity (PFR) were taken at baseline and during isometric handgrip exercise.
- Twelve healthy controls underwent the same measurements.
Main Results:
- Vp showed no significant changes in any group during isometric handgrip exercise.
- Pulsed Doppler indices in patients with lower E/A ratios shifted towards a pattern seen in patients with higher E/A ratios.
- Healthy controls exhibited decreased E velocity, decreased E/A ratio, and increased IVRT.
Conclusions:
- Color M-mode Vp appears to be an afterload-independent measure of diastolic function in patients with moderate to severe cardiomyopathy.
- Conventional pulsed Doppler indices are more sensitive to acute afterload alterations induced by isometric exercise in this population.
Background And Objective:
Color M-mode flow propagation velocity (Vp) was shown to be a preload-independent measure of diastolic function. To study the effects of an increase in afterload induced by isometric handgrip exercise on diastolic function assessment in patients with cardiomyopathy, we measured Vp and conventional Doppler indices at baseline and at 30% of predetermined maximum handgrip strength.
Methods:
Twenty-four patients with systolic dysfunction were divided into two groups: Group I comprising 12 patients with E/A < 1 (early filling velocity/atrial contraction velocity) and Group II comprising 12 patients with E/A > 1. All the patients underwent measurement of Vp, E velocity, its deceleration time (DT), A velocity, isovolumic relaxation time (IVRT), and pulmonary atrial flow reversal velocity (PFR) at baseline and at 30% of predetermined maximum handgrip strength. Twelve healthy controls underwent these same measurements.
Results:
When comparing baseline to peak echocardiographic data, no significant changes were noted in Vp in any of the groups while a shift of pulsed Doppler indices of Group I toward a pattern closer to that of Group II was noted and a decrease in E velocity and E/A ratio with an increase in IVRT occurred in healthy controls.
Conclusions:
Color M-mode flow propagation velocity seems to be an afterload-independent measure of diastolic function in patients with moderate to severe cardiomyopathy while pulsed Doppler indices are more sensitive to loading conditions induced by isometric exercise.
