A B S T R A C T Coarctation of the mid-thoracic aorata was surgically produced in mongrel dogs which were sacrificed from 4-12 wk after the operation. As compared to the findings in control animals, the sodium, chloride, and water content of the hypetensive portion of the coarcted thoracic aorta was significantly elevated, whereas the electrolyte and water content of the relatively normotensive portion of the coarcted aorta was normal. The sodium, potassium, and water content of the pulmonary artery, skeletal muscle, and cardiac muscle of the coarcted dog was not altered. These observations suggest that an elevated arterial pressure may influence the electrolyte and water composition of the arteries.The arterial pressure also may influence the content and synthesis of acid mucopolysaccharides (MPS) in the arteries since the content of sulfated MPS and the incorporation of injected radiosulfate into sulfated MPS were significantly increased in, the hypertensive portion of the coarcted thoracic aorta but were significantly reduced in the relatively normotensive ("hypotensive") portion of the coarcted aorta. The observed increase in MPS may have been a factor directly responsible for the increase in the sodium content of the hypertensive aorta since MPS can act as polyelectrolytes and bind cations.Although the arterial pressure may influence certain metabolic functions in the arteries, it did

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Left ventricular ejection fraction was determined by two-dimensional echocardiography in 54 patients using a new method, and the results were compared with the ejection fraction by gated blood pool scanning. The ventricle was modelled as a tubular base section joined to a hemielliptical apex section, each containing four quadrants. Segmental contraction was scored in twelve regions of the ventricle by visual assessment of wall motion during videotape playback of echocardiograms. The twelve contraction scores were converted to dimensional shortening and used to calculate separate ejection fractions for each of the eight quadrants. These eight values were averaged to obtain the left ventricular global ejection. Fifty-eight patients with echocardiograms and gated scans within 7 days of each other were selected retrospectively from among the routine studies in the clinical laboratory. Image quality was adequate for wall motion scoring in 54 patients. The correlation coefficient between echocardiography and gated scanning was 0.92 with a standard error of 7.5. The accuracy of the method was very similar for studies with the most homogeneous wall motion compared to those with the most dyssynergy and in patients with the lowest ejection fractions compared to those with the highest ejection fractions. In 31 patients, scoring of contraction was performed independently by two different observers. Both observers attained an identical correlation with gated scan of 0.92. The interobserver correlation coefficient was also 0.92 with a standard error of 7.8. It is concluded that this method of estimating left ventricular ejection fraction is simple to use and may provide a clinically acceptable degree of accuracy in a wide variety of conditions of left ventricular function.