Archive for the ‘Hyperkinesis’ Category

Rapid Resolution of Hyperkinesis After Exercise: ConclusionQuantitative Two-Dimensional Echocardiography
While there are few data on intraobserver variability in wall thickness measurements, the 8 percent interobserver variability was similar to the 6 to 8 percent reported by others. These previous studies, however, used area-based methods for wall thickness measurements, tracing the endocardial and epicardial borders, and measuring myocardial area at end-dias-tole and end-systole. We used a linear method, since acoustic shadowing from ribs and lung at peak exercise prevented the visualization of the entire endocardial circumference. While an area method may be more robust than a linear method because of spatial averaging, we averaged multiple linear dimensions. Such clinically useful Unear measurements of wall thickness obtained from two-dimensional echocardiograms are similar to those obtained with M-mode echocardiography. canadianfamilypharmacy

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The major finding of this study was that maximal systolic wall thickening occurred within 2 min after exercise, then returned to baseline, corresponding to changes in hemodynamics.
Temporal Variability in Thickening
Exercise two-dimensional echocardiography is used to identify wall motion abnormalities that develop during ischemia in patients with coronary artery disease. When myocardial perfusion is inadequate during the increased oxygen consumption associated with exercise, wall motion is reduced. In contrast, normal myocardium, after exercise, is hyperkinetic, with increased wall thickening, decreased systolic cavity size, and essentially normal diastolic dimensions. However, there are few studies on the time course of normal systolic function after exercise. In an M-mode echocardiographic study of normal subjects, Berberich et al demonstrated a trend toward baseline function by 3 min after exercise; by 4 to 5 minutes, function had returned to baseline. In their study, cavity dimensions, not wall thicknesses, were measured.
In our study, the return of systolic wall thickening to baseline occurred with the return of hemodynamics toward normal. This reflects the influence of circulating catecholamines on both contractility (specifically, wall thickening) and heart rate. Since systolic wall thickening returned to baseline at 2 to 4 min after exercise, our study provides objective data in support of the recommendations of other authors that imaging should be completed within 2 min of peak exercise 13.16.20 jn order to assess maximal wall thickening.
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Rapid Resolution of Hyperkinesis After Exercise: ResultsThere were significant (p<0.0001) changes over the time course of the study for heart rate, systolic BP, and rate pressure product (Table 1). Each postexercise heart rate mean was significantly increased over baseline (p<0.01). There was a significant elevation (p<0.005) of systolic BP until 5 to 7 min postexercise when there was a return to baseline. The pattern of elevation and recovery of the rate pressure product was the same as for systolic BP with a significant elevation (p<0.001) until 5 to 7 minutes postexercise when there was a return to baseline.
Wall thickness change could be measured in six of the eight subjects at 0 to 2 minutes postexercise. In the parasternal long-axis view, wall thickness change could be measured from the basal anterior septum (n = 6) and basal posterior region (n = 5), but not from the mid anterior or mid inferior lateral regions. In the parasternal short-axis view, wall thickness could be measured from the mid-inferior lateral (n = 5), mid-anterior septal (n = 3), mid-inferior (n = 2), and mid-septal (n = 1) regions, but not from the mid-anterior and lateral regions. Wall thickening is reported for the regions with the highest yields for measurement: in the parasternal long-axis view, the basal anterior septal and basal posterior regions, and in the parasternal short-axis views, the mid-anterior septal and midinferior lateral regions. These four regions were included in the analysis of variance model.
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Only the parasternal long- and short-axis views were used for wall thickening measurements; endocardial surfaces were not consistendy visualized from the apical views at peak exercise. End-diastolic and end-systolic frames were digitized from videotape using a frame grabber (Nova Microsonics Color-Vue II) (512 X 240 x 6 bit matrix). End-diastole was defined as the frame just prior to, or during, mitral valve closure. End-systole was defined as the frame prior to mitral valve opening in long-axis views or as the smallest cavity area in short-axis views.® Parasternal long- and short-axis views were divided into four and six regions, respectively (Fig 1). Regional end-diastolic and end-systolic wall thickness was measured by averaging ten lengths evenly distributed within each region, using the leading edge-to-leading edge method.
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Rapid Resolution of Hyperkinesis After Exercise: MethodsExercise-induced wall motion abnormalities, visualized by two-dimensional echocardiography, suggest the presence of coronary artery disease with a sensitivity of 70 to 94 percent, and a specificity of 67 to 92 percent. Hyperkinetic wall motion, on the other hand, is predictive of an excellent prognosis. The normal, hyperkinetic response to exercise is transient; and there are few data on the time course of resolution. The duration of normal, hyperkinetic wall motion is important to recognize because of the implications regarding prognosis. Our purpose, therefore, was to measure regional wall thickening in normal subjects before and serially after exercise, and to determine the duration of exercise-induced hyperkinesis.
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