Diagnostic applications of the platinum electrode catheter

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Human heart weight at high altitude

The weight of the right ventricle, left ventricle, and septum determined in 98 hearts of high altitude (12,300 feet) residents in Peru and in 86 hearts from sea level in the continental United States revealed that right ventricular hypertrophy is no greater at high altitude than at sea level in the stillborn-newborn infant heart. Right ventricular weight relative to total heart weight at high altitude exceeds that at sea level beginning about 30 days after birth and reaches a plateau at 56 days. Thereafter the degree of relative right ventricular hypertrophy changes only slightly through the adult years. No evidence was found of postnatal atrophy of the right ventricle either at sea level or high altitude nor of septal hypertrophy accompanying the right ventricular hypertrophy in high altitude. The degree of right ventricular hypertrophy was moderate and variable, and corresponded to the moderate, variable pulmonary hypertension previously demonstrated in high altitude residents. Since total heart weights are similar at high altitude and sea level and since high altitude subjects have a smaller body size, the heart weight/body weight ratio is probably greater in the high altitude subject.

Effect of oxygen upon pulmonary circulation in acclimatized man at high altitude

The response to breathing 100% oxygen was studied in 26 acclimatized residents of the Peruvian Andes at altitudes of 12,300 and 14,200 ft. Arterial oxygen saturation increased from 86% to 96%. Mean pulmonary artery pressure decreased by 5 mm Hg and cardiac output did not change. Calculated pulmonary arteriolar resistance was lowered. Pulmonary artery pressure during oxygen breathing was not decreased to normal values observed at sea level. The data suggest the presence of two factors responsible for the increase in pulmonary arteriolar resistance at high altitude: 1) hypoxic vasoconstriction which is reversed by oxygen breathing and 2) anatomic alterations which are not affected by oxygen breathing. Oxygen breathing at high altitude also produced a slowing of the heart rate and increased the relative height of the secondary or tidal wave of the brachial arterial pressure pulse.

pulmonary arteriolar resistance and 100% oxygen; arterial pulse contour–effect of 100% oxygen at high altitude; pulmonary arteriolar resistance–nature of in high altitude; hypoxic vasoconstriction at high altitude–reversal by 100% oxygen breathing; oxygen breathing–comparison of effect on pulmonary circulation at high altitude and sea level

Submitted on May 8, 1964

Pulmonary circulation in acclimatized man at high altitude

Cardiac catheterization studies have been carried out in 30 acclimatized adults at an altitude of 12,3000 ft in the Peruvian Andes. Mean pulmonary artery pressure was 22 mm. Hg (range 14-31 mm Hg) compared to 15 mm Hg (range 11-17 mm Hg) observed in sea-level subjects. The pulmonary artery wedge pressure was normal and calculated pulmonary arteriolar resistance was increased by 180% over sea-level values. The arteriovenous oxygen content difference and oxygen consumption were slightly greater at high altitude, but the cardiac output was normal. There was no relationship between hematocrit and pulmonary artery pressure or resistance, suggesting that in the high-altitude resident, blood viscosity in a hematocrit range of 40-78% does not significantly affect resistance to blood flow. Nine subjects studied at 14,200 ft had the same mean pulmonary artery pressure (22 mm Hg, range 17-32 mm Hg) as the larger group at 12,300 ft.

pulmonary artery pressure

Submitted on May 8, 1964

Effect of exercise on the metabolism of fatty acids in the dog

Dogs with indwelling arterial and venous catheters worked on a treadmill for 25–30 min. Exercise decreased the plasma free fatty acid (FFA) concentration and increased the blood glucose. In the postexercise period, the plasma inorganic P showed a significant decrease. Experiments with C14-palmitate and C14-oleate showed that the decrease of the plasma FFA was due partly to an elevated uptake and partly to a reduced rate of release into the blood. Infusions of Na lactate to resting dogs induced a marked increase in specific activity of plasma FFA, due to an inhibition of release. In spite of the reduced rate of release of FFA, the oxidation of the C14-fatty acid was considerably increased during exercise (three- to fourfold). No direct relationship seems to exist between the turnover rate of plasma FFA and the rate of oxidation of fatty acids.