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[Effect of age on left ventricular relaxation: pulsed Doppler echocardiographic evaluation]
N Kuroiwa1, K Nakamura, H Kawagoe
1Second Department of Internal Medicine, Faculty of Medicine, Kagoshima University.
Insights
Pulsed Doppler echocardiography offers a new noninvasive method to assess left ventricular relaxation. This technique accurately measures isovolumic relaxation flow, correlating well with invasive measures and showing significant age-related changes.
Area of Science:
- Cardiology
- Medical Imaging
- Physiology
Context:
- Assessing left ventricular relaxation noninvasively is challenging, with limited indices available.
- Pulsed Doppler echocardiography allows precise observation of intracardiac blood flow.
- Existing methods like M-mode echocardiography and phonocardiography have limitations in evaluating relaxation during the isovolumic period.
Purpose:
- To evaluate the left ventricular relaxation property using pulsed Doppler echocardiography.
- To investigate the effect of age on left ventricular relaxation.
- To determine the relationship between invasive and noninvasive parameters of left ventricular relaxation.
Summary:
- Pulsed Doppler echocardiography measured isovolumic relaxation flow (IRT, AcT, AcR) in patients and healthy individuals.
- IRT, ln AcT, and ln AcR correlated significantly with the invasive time constant T of left ventricular pressure fall.
- Significant correlations were found between age and the Doppler-derived relaxation indices in healthy subjects.
Impact:
- Pulsed Doppler echocardiography provides a valuable noninvasive tool for assessing left ventricular relaxation.
- This method can help understand age-related changes in cardiac function.
- Findings may lead to improved diagnostic capabilities for diastolic dysfunction.
Abstract:
There is no noninvasive index to assess the left ventricular relaxation property during the isovolumic relaxation period except for the isovolumic relaxation time, which is derived from M-mode echocardiography or phonocardiography. The intracardiac blood flow can now be precisely observed using pulsed Doppler echocardiography. We evaluated the left ventricular relaxation property and studied the effect of age on the relaxation property using this method. Cardiac catheterization and pulsed Doppler echocardiography were performed for 27 patients with various heart diseases, none of whom had wall motion abnormalities on left ventriculography, to determine the relationships between invasive and noninvasive parameters. The effects of age were examined in 25 normal healthy persons ranging in age from 26 to 69 years. In all cases, the intracardiac blood flow during the isovolumic relaxation period (isovolumic relaxation flow) as obtained by pulsed Doppler echocardiography was laminar, and directed from the base toward the apex of the left ventricle. The duration of this flow (the time interval from the beginning to the end of this flow; IRT), the acceleration time (the time interval from the beginning to the peak velocity; ACT) and the acceleration rate (the slope of the beginning to the peak velocity; AcR) were measured, and IRT, ln AcT (natural logarithm of AcT) and ln AcR (natural logarithm of AcR) were compared with the parameters obtained by cardiac catheterization. The time constant T of the fall in left ventricular pressure during the isovolumic relaxation period, which was proposed as an index of the left ventricular relaxation property, correlated well with IRT (r = 0.82, p less than 0.001), ln AcT (r = 0.69, p less than 0.001) and ln AcR (r = -0.77, p less than 0.001), but there were no significant correlations with maximum blood pressure, left ventricular ejection fraction, maximal positive dp/dt or the left ventricular end-diastolic volume index. Age and these three Doppler indexes in normal healthy persons correlated significantly as follows; IRT (r = 0.80, p less than 0.001), ln AcT (r = 0.60, p less than 0.001) and ln AcR (r = -0.61, p less than 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)