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Echocardiographic determinants of mitral early flow propagation velocity
Paolo Barbier1, Antonio Grimaldi, Marina Alimento
1Echocardiography Laboratory, Centro Cardiologico Fondazione Monzino, IRCCS, Istituto di Cardiologia dell'Universita' di Milano, Milan, Italy. pbar@iol.it
Insights
Transmitral color Doppler early diastolic flow propagation velocity (Vp) is influenced by left ventricular (LV) systolic function and wall motion abnormalities, not solely by LV relaxation in a general patient population.
Area of Science:
- Cardiology
- Echocardiography
- Diastolic Function Assessment
Background:
- Transmitral color Doppler early diastolic flow propagation velocity (Vp) is linked to left ventricular (LV) relaxation time constant (tau).
- Previous studies correlated Vp with LV relaxation in specific heart conditions like dilated cardiomyopathy and ischemic heart disease.
Purpose of the Study:
- To determine the independent impact of LV systolic function, geometry, and relaxation on Vp.
- To investigate these factors in an unselected outpatient population with diverse cardiac conditions.
Main Methods:
- Studied 30 normal subjects and 130 patients with conditions including hypertensive LV hypertrophy, valve disease, cardiomyopathies, and coronary artery disease.
- Noninvasively measured LV geometry, mass, systolic function, wall motion dyssynergy, and diastolic function (abnormal relaxation or restrictive filling).
- Analyzed Vp using multiple regression and multivariate analysis of variance.
Main Results:
- Vp values were similar between normal subjects and the overall patient group.
- In normal subjects, Vp determinants included isovolumic relaxation time, cardiac index, and mitral E-wave velocity-time integral.
- In the overall population, LV ejection fraction, segmental wall dyssynergy, isovolumic relaxation time, and age were main determinants; wall dyssynergy independently reduced Vp.
Conclusions:
- In a general clinical population, Vp is not solely dependent on prolonged LV relaxation.
- LV systolic dysfunction and segmental wall dyssynergy are significant independent determinants of Vp.
- Vp is a multifactorial parameter influenced by both systolic and diastolic factors.
Abstract:
Transmitral color Doppler early diastolic flow propagation velocity (Vp) has been correlated with the left ventricular (LV) relaxation time constant tau in dilated cardiomyopathy and ischemic heart disease. The aim of this study was to investigate the independent influence of LV systolic function and geometry, and of LV relaxation, on Vp in an unselected outpatient population. We studied 30 normal subjects and 130 patients (hypertensive LV hypertrophy, aortic valve stenosis or prosthesis, hypertrophic cardiomyopathy, coronary artery disease, dilated cardiomyopathy, aortic or mitral valve regurgitation). In all, we noninvasively measured LV geometry, mass, systolic function, wall motion dyssynergy, and diastolic function (abnormal relaxation or restrictive LV Doppler filling patterns). The Vp was similar in normal subjects and in patients (51 +/- 14 vs 53 +/- 25 cm/s). In normal subjects, the determinants of Vp at multiple regression analysis were isovolumic relaxation time, 2-dimensional cardiac index, and mitral E-wave velocity-time integral. In all, the main determinants were LV ejection fraction, percent of segmental wall dyssynergy, and isovolumic relaxation time and age. The Vp was highest in hypertrophic (75 +/- 25 cm/s, p <0.05 vs normal subjects) and lowest in dilated (35 +/- 13 cm/s, p = NS) cardiomyopathy. During multivariate analysis of variance, percent of wall dyssynergy (but not diffuse LV hypokinesia) independently reduced Vp (p = 0.02). The latter was not influenced by the LV filling pattern. Thus, in an unselected clinical population, prolonged relaxation per se does not influence Vp if LV systolic dysfunction and/or wall dyssynergy is absent-the latter factors are important independent determinants of Vp, which is determined by multiple factors.