The Journal of Thoracic and Cardiovascular Surgery, Vol 101, 465-472, Copyright © 1991 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Differing susceptibilities to cold preservation of rat atria and ventricles
H Noguchi, I Muramatsu, R Muraoka, Y Chiba and S Kigoshi
Second Department of Surgery, Fukui Medical School, Japan.
The susceptibilities of atria and ventricles to cold preservation were
studied in rat hearts. Rat hearts were stored in Collins' solution at 4
degrees C for 0, 12, or 24 hours, and the atrial and ventricular function
was measured in a working heart model and in isolated atrial and papillary
muscle preparations. In working heart preparations, cardiac output
decreased to 0 ml/min and other parameters of ventricular function
(systolic and end-diastolic pressure and dP/dt of the left ventricle)
markedly deteriorated after 12 hours of preservation. After 24 hours, no
contraction of the left ventricle was observed despite the presence of
atrial contraction. In isolated atrial muscle preparations, the rate of
spontaneous beating of the right atrium was not affected by cold
preservation. The twitch contractions of right and left atria were
attenuated but elicited after 24 hours. In electrically driven papillary
muscles, twitch contractions were also markedly attenuated by 12 hours of
preservation and were abolished after 24 hours. The positive inotropic
effect of isoproterenol was also markedly attenuated in the atrial
preparations by cold preservation. However, the positive chronotropic
response to isoproterenol and the negative chronotropic and inotropic
responses to carbachol were little affected by cold preservation.
Intramural cholinergic and adrenergic nerve stimulation produced first
negative and then positive effects on the beating rate and twitch
contraction in the isolated right atria. Cold preservation selectively
attenuated and finally abolished the adrenergic responses. In the
ventricles, the adenosine triphosphate and creatine phosphate content
significantly decreased and the lactate content increased with an increase
in the preservation period. On the other hand, changes of such metabolites
in the atria were either not observed or were much smaller. These results
suggest that atrial function is maintained better than ventricular function
in the cold- preserved heart.
