HAeMODYNAMIC CHANGES IN CHRONIC CONSTRICTIVE PERICARDITIS DURING EXERCISE AND HISTAMINE INFUSION

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Abstract
Hemodynamic observations were made in four men with chronic constructive pericarditis, who were subjected to heart catheterization. All four subjects had low stroke volumes at rest and the cardiac output was low in two of them. The right atrial and the PCV pressures (pulmonary artery wedge pressures) were high, but the pulmonary vascular resistance was fairly normal. During exercise there was only slight increase in cardiac output and the arteriovenous difference in oxygen content of the blood increased to high values. The right atrial and PCV pressures increased considerably. During an intravenous infusion of histamine the cardiac output and the stroke volume increased, and were higher than during exercise. The calculated stroke work was also increased by histamine. During histamine infusion the right atrial pressure decreased, and the PCV pressure increased, but comparatively little. The mechanism of this effect of histamine is discussed and it is concluded that a direct action of histamine on the heart, with an increase of its contractile power, is the most likely explanation.