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This study was performed to evaluate the effects of respiration on diastolic blood flow velocity and its relevance for the determination of pulsed Doppler reference values from diastolic blood flow. Doppler signals were recorded from both the atrial and ventricular sides of the mitral valve and the tricuspid valve in 215 healthy volunteers (120 males and 95 females, with ages ranging from 1-65 years). Respiratory signals were recorded simultaneously by a mercury strain gauge around the thorax. From the medians of Doppler spectra the maximum velocity during early diastole (VmaxE), during atrial contraction (VmaxA) and the ratio between VmaxE and VmaxA (EA ratio) were obtained. On the atrial side of the tricuspid valve, VmaxE and VmaxA were significantly higher during inspiration than during expiration. On the ventricular side of the tricuspid valve, this was only found for VmaxE. On the atrial side of the mitral valve, VmaxE and VmaxA were significantly lower during inspiration than during expiration. At the ventricular side of the mitral valve, this was found only for VmaxE. No significant effect of respiration was found on the EA ratio. We conclude that there is a respiration-related effect on VmaxE and VmaxA. However, no significant effect is found on the EA ratio. Thus, for the determination of the EA ratio in intersubject studies, information about the respiratory cycle is not relevant.

The effects of aging on cardiac blood flow velocities are important as a description of the natural history of the aging process and as a reference for evaluation of the aging cardiovascular system. We therefore studied these effects in 215 healthy volunteers, 120 males and 95 females, between 1 and 65 years old. Pulsed Doppler signals were recorded proximal and distal to the mitral (M) and tricuspid (T) valves, in the left ventricular outflow tract (LVOT), in the ascending aorta (AAO), in the right ventricular outflow tract (RVOT), and in the pulmonary artery (PA). Systolic (S) flow velocity patterns consist mainly of one peak. Diastolic blood flow velocity is characterized by two peaks: one due to early filling (E) of the ventricle and a second as a result of atrial contraction (A). All peaks are characterized by the maximum of the median velocity curve (Vmax). With age increasing from 1 to 65 years, VmaxS decreases in the AAO (40%) and PA (10%), VmaxE decreases on both sides of the M valve (proximal-50%; distal-30%), and the T valve (proximal-20%; distal-30%). However, with increasing age VmaxS increases in the LVOT (25%), and VmaxA increases on both sides of the M valve (proximal-20%; distal-50%) and proximal to the T valve (30%). VmaxS in the RVOT and VmaxA distal to the T valve did not show a relation with age. These observations demonstrate that in a normal population Vmax in the heart and great vessels is age dependent at most sites.(ABSTRACT TRUNCATED AT 250 WORDS)

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