Effect of left ventricular wall mass on Doppler filling patterns in the developing normal human heart.
To assess gestational age- and growth-related changes in left ventricular (LV) size, LV wall, and LV transmitral flow velocity patterns, 2-dimensional (2-D) and Doppler echocardiographic studies were performed in 89 normal fetuses aged 16 to 38 weeks. Serial studies were designed in 7 fetuses. Variables measured from 4-chamber views were chamber areas and myocardial wall areas. From these measurements, area shortening fraction and ratio of myocardial wall area to end-diastolic chamber area were calculated. LV end-diastolic chamber area and myocardial wall area increased exponentially with advancing gestational age (r = 0.88 and 0.90, respectively, p < 0.001). Area shortening fraction showed no significant changes with gestational age. Ratio of myocardial wall area to LV end-diastolic chamber area decreased gradually with increasing gestational age (r = -0.77, p < 0.001). With increasing gestational age, mitral peak velocities of early diastole increased (r = 0.82, p < 0.01) with little change in peak velocity during atrial contraction. Multiple regression analysis showed that age-related increases in peak velocity of early diastole were related to advancing gestational age and also to decreases in ratio of myocardial wall area to LV end-diastolic chamber area. Low peak filling velocities during early diastole in younger fetuses may be related partly to relative increase in LV wall mass. The gestational age-related decreases in LV wall mass may be one of the important mechanisms of gestational age-related alterations in diastolic properties, especially relaxation processes.
Harada
K
K
Department of Pediatrics, Akita University School of Medicine, Japan.
Tsuda
A
A
Shiota
T
T
Rice
M J
MJ
Ishii
M
M
McDonald
R W
RW
Sahn
D J
DJ
D001783:Blood Flow Velocity / Q000502:physiology; D015150:Echocardiography, Doppler; D005260:Female; D005318:Fetal Heart / Q000000981:diagnostic imaging / Q000502:physiology*; D005865:Gestational Age; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D009200:Myocardial Contraction / Q000502:physiology*; D015588:Observer Variation; D011247:Pregnancy; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal / Q000379:methods; D016276:Ventricular Function