Mechanical characteristics of the globally ischaemic heart.
OBJECTIVE
The aim was to study the effects of global ischaemia on the mechanical properties of the myocardium.


METHODS
Myocardial ischaemia was achieved by incubating the hearts of 160 rats in normal saline at 37 degrees C for periods of up to 24 h. To obtain different degrees of contracture, excess pressure (up to 150 mm Hg) was created in the left ventricles of subgroups of hearts. After incubation the hearts underwent mechanical loading.


RESULTS
Ischaemic contracture of cardiomyocytes led to increased rigidity and strength of the myocardium. A pressure of 50 mm Hg or higher blocked the increase in strength and rigidity of the ischaemic myocardium.


CONCLUSIONS
It appears likely that in a functioning heart cardiomyocyte contracture in an ischaemic zone can only develop during the diastolic phase. A decrease in diastolic duration and/or an increase in diastolic pressure in the left ventricle may prevent increases in strength and rigidity of the ventricular wall after an infarct and promote the development of aneurysm and possible cardiac rupture.
Shlyachover
V E
VE
Central Science Laboratory, Gorkii Medical Institute, Ukraine.
Zenin
O K
OK
D000818:Animals; D001696:Biomechanical Phenomena; D003971:Diastole; D004195:Disease Models, Animal; D005260:Female; D006321:Heart / Q000503:physiopathology*; D008297:Male; D017202:Myocardial Ischemia / Q000503:physiopathology*; D011312:Pressure; D051381:Rats; D011919:Rats, Inbred Strains