Elektrokardiographische und histologische Untersuchungen bei der Sauerstoffvergiftung

Heart muscle necroses following normobaric hyperoxia: modification by beta-blocking agents and calcium antagonists

Heart muscle necroses can be produced in rabbits by normobaric hyperoxia. The pathogenesis of these lesions is controversial. In our investigations we found that such necroses can be prevented by beta blockers, but not by a calcium antagonist. This can be explained by the different action of the two drugs on the coronary arteries. The result supports the view that heart muscle necroses after normobaric hyperoxia are a direct toxic effect of oxygen on the heart muscle fibers.

Light and electron microscopic examinations of experimentally produced heart muscle necroses following normobaric hyperoxia

Heart muscle necroses following normobaric hyperoxia as examined under a light microscope occur after 40 hours exposure in the rabbit and increase in intensity with prolongation of the exposition time. Simultaneous arterial blood gas analysis excludes a hypoxemis as the cause, In addition electron microscopic examination of the necroses demonstrate the primary changes in the myofibrils but not in the mitochondria. The ultramorphological picture is however, quite similar to the myocardial necroses after epinephrine application in the rabbit. A pathogenetic relationship between heart muscle necroses after normobaric hyperoxia and after epinephrine should be considered.