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Accession Number:
ADA027973
Title:
Cardiac Pathology Associated with High Sustained +Gz: Subendocardial Hemorrhage
Descriptive Note:
Final rept. Feb 1973-May 1976
Corporate Author:
SCHOOL OF AEROSPACE MEDICINE BROOKS AFB TX
Report Date:
1976-01-01
Pagination or Media Count:
10.0
Abstract:
Adult miniature swine were exposed to various levels and durations of Gz. After exposure, all swine were euthanized and necropsied. Gross, histologic, and electronmicroscopic observations were made on the heart tissue. Subendocardial hemorrhage SEH was commonly found in the left ventricle, rarely in the right ventricle, and its severity was directly related to a level and duration of G exposure, b heart rate, and c catecholamine activity. SEH was made more severe with i.v. atropine 4 mg, and prevented with i.v. propranolol 20 mg. Heart hemorrhage was usually limited to the immediate subendocardial region and frequently surrounded Purkinjes fibers. In severe cases, however, hemorrhages penetrated several millimeters into the heart muscle and sometimes penetrated Purkinjes fibers. Restraint of unanesthetized swine in the centrifuge couch, low G-levels, andor i.v. injections of atropine or epinephrine produced minimal SEH lesions.
Distribution Statement:
APPROVED FOR PUBLIC RELEASE
