PubMed · 1245111
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S J Kra. 1976. Basic echocardiography: an over-view.. https://pubmed.ncbi.nlm.nih.gov/1245111/
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OBJECTIVES: The purpose of this study was to test the hypothesis that invasively derived jet variables including regurgitant orifice area and momentum determine the characteristics of Doppler color flow jets in patients with aortic regurgitation. BACKGROUND: In vitro studies have demonstrated that the velocity distribution of a regurgitant jet is best characterized by the momentum of the jet, which incorporates orifice area and velocity of flow through the orifice. METHODS: Peak jet momentum, peak flow rate and regurgitant orifice area were determined with intraaortic Doppler catheter and cardiac catheterization techniques in 22 patients with chronic aortic regurgitation. These invasively derived variables were compared with apical and parasternal long-axis Doppler color echocardiographic variables obtained in the catheterization laboratory. RESULTS: Jet momentum increased significantly with the angiographic grade of regurgitation. The apical color jet area of aortic regurgitation increased linearly with jet momentum and regurgitant orifice area in vivo, but the correlations were only moderately good (r = 0.63 and 0.65, respectively). Color jet length also increased linearly with jet momentum and with regurgitant orifice area. There was only a trend for Doppler color jet width to increase with all invasively derived jet variables. CONCLUSIONS: Whereas jet area by Doppler color flow imaging is directly related to both orifice area and jet momentum in vivo, Doppler color variables measured in planes normal to the orifice do not correlate well enough with either jet momentum or regurgitant orifice area to predict jet flow variables in patients with aortic regurgitation. It is likely that the important influence of adjacent boundaries will limit the use of the velocity distribution of aortic regurgitant jets for determining the severity of disease.
Magnetocardiograms (MCGs) were recorded by means of a second-derivative SQUID (superconducting quantum interference device) magnetometer in 20 normal subjects and 28 patients with left ventricular overload to analyze the activation sequence of the heart and amplitude of estimated current source. In the normal subjects, the dipole was directed to the left and gradually superiorly 40 ms after the beginning of the QRS wave mainly due to the activation of the left ventricle. In the patients with hypertension, the direction and location of the dipoles were similar to those of the normal subjects, but their dipole moments were increased. In the patients with mitral regurgitation, the dipoles of late QRS were directed more inferiorly than in the normal subjects and their amplitude was increased. In the patients with aortic valve disease, the amplitude of the dipoles was increased markedly and their location was deviated more to the left than the dipoles of the normal subjects. We established the criterion for diagnosis of LVO from the dipole moment of 50 ms of 3.13 x 10(-3) A or more. The sensitivity of this criterion is significantly higher in the diagnosis of left ventricular overload than the electrocardiogram (ECG). The present study shows that the moving dipole method is useful to determine the increased electromotive force in patients with left ventricular overload and that sensitivity in diagnosis of left ventricular overload is increased.
To clarify the mechanisms for an abnormal radionuclide left ventricular (LV) ejection fraction response to exercise in patients with chronic, severe aortic regurgitation (AR), we studied seven control patients and 21 patients with AR. We used exercise radionuclide angiography and catheterization of the right and left sides of the heart to obtain a calculation of LV chamber elastance. The control and AR groups had similar heart rates, systolic blood pressure responses to exercise, and exercise durations. In both patient groups, LV end-diastolic volume did not change with exercise. In contrast to the decrease in LV end-systolic volume (p less than 0.05) and increase in LV ejection fraction (p less than 0.01) in the control group, LV end-systolic volume in the patients with AR increased, resulting in little change in their LV ejection fraction. By stepwise multiple regression analysis, the radionuclide LV ejection fraction at peak exercise in patients with AR was determined by the LV chamber elastance, LV end-systolic volume, and stroke volume at peak exercise (cumulative r = 0.79, p less than 0.02); the change in radionuclide LV ejection fraction from rest to peak exercise was determined by the corresponding change in systemic vascular resistance, regurgitant index, and LV end-diastolic and end-systolic volumes (cumulative r = 0.88, p less than 0.02). These data demonstrate that in patients with AR, the radionuclide LV ejection fraction at peak exercise is principally determined by the cumulative effects of chronic, severe AR on LV systolic chamber performance, and the change in radionuclide LV ejection fraction from rest to peak exercise is principally established by peripheral vascular responses.