Cardiovascular injury from blunt thoracic impact of epinephrine and isoproterenol injected rabbits.

Nonpenetrating thoracic impact of 10 anesthetized rabbits injected with epinephrine and experiencing transient hypertension resulted in 4 incidents of traumatic rupture of the left ventricle. Impact of similar severity did not produce ventricular injury (p less than 0.01) in either 11 control or 10 animals injected with isoproterenol and experiencing transient hypotension. Immediate death (p less than 0.001) and aortic rupture (p less than 0.05) were most frequent in epinephrine injected animals. Impact during cardiac systole produced more frequent cardiovascular lesions in the epinephrine injected animals than during diastolic loading (p less than 0.001), whereas the cardiac phase was not a significant factor in the thoracic injuries of the control or isoproterenol injected animals. The experiments indicate that the precondition of the myocardium is an important factor in the incidence of ventricular and major vascular rupture in nonpenetrating thoracic impact.