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Effect of postural stress on left ventricular performance using the continuous-wave Doppler technique
R A Brown1, K A McCormick, P V Vaitkevicius
1Laboratory of Behavioral Sciences, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224.
Chest
|September 1, 1991
Summary
Postural shifts to sitting and standing reduce left ventricular performance indices, including peak acceleration and velocity, as measured by continuous-wave Doppler. These changes occur consistently across all adult age groups.
Area of Science:
- Cardiology
- Physiology
- Medical Imaging
Background:
- Assessing left ventricular (LV) performance is crucial for cardiovascular health.
- Continuous-wave Doppler echocardiography is a non-invasive tool for evaluating cardiac function.
- Orthostatic stress can reveal subclinical cardiovascular abnormalities.
Purpose of the Study:
- To investigate the impact of postural changes (supine, sitting, standing) on Doppler-derived LV performance indices in healthy adults.
- To determine if age influences the response of LV performance to orthostatic stress.
Main Methods:
- Sixty-nine healthy volunteers (aged 20-86 years) underwent suprasternal continuous-wave Doppler measurements.
- Measurements were taken in the supine position and 2 minutes after assuming sitting and standing postures.
- Key Doppler indices analyzed included peak acceleration (PKA), peak velocity (PKV), stroke distance (SD), and velocity integral of the heart rate (VIH).
Main Results:
- All LV performance indices (PKA, PKV, SD, VIH) significantly decreased with increasing orthostasis (p < 0.001).
- Heart rate showed a modest but significant increase with postural changes (p < 0.001).
- These age-independent postural effects were observed across all age groups studied.
Conclusions:
- Orthostasis in healthy individuals leads to a consistent reduction in continuous-wave Doppler indices of left ventricular performance.
- Age does not significantly alter the response of these Doppler indices to postural shifts.
- Continuous-wave Doppler can effectively detect hemodynamic changes associated with orthostatic stress in normal subjects.