New developments in the isolated working heart: a comparison of neonatal, immature, and adult rabbits after sixty minutes of ischemia in respect to hemodynamic and biochemical parameters.
Hemodynamic and biochemical changes were studied on 36 white ELCO-rabbits, seven adult older than 150 days, seven immatures between 21 and 27 days, and seven neonatals between 7 and 14 days. Five supplementary hearts of each age group served for preischemic biochemical values. Protection during 60 min of global ischemia was provided by topical cooling and selective coronary perfusion with Bretschneider cardioplegia (8 degrees C). A comparison between pre- and postischemic results showed decreases in coronary flow in the adult (p < 0.004), aortic flow (p < 0.04), cardiac output (p < 0.02), and stroke volume (p < 0.02) in the neonate. The preservation of ATP and CP was sufficient in the adult and immature myocardium, whereas a significant decrease in neonatal ATP was found (p < 0.01). According to these findings we consider immature myocardium to be more resistant against ischemia than the two other age groups. The apparatus used is a development of the conventional working heart, but combines a physiological flow-pressure relation, with instruments guaranteeing high accuracy, devices for drug application, and fits for different sizes of hearts. Therefore, this new approach promises to be of clinical relevance for investigations on the improvement of myocardial protection in both adults and children.
Podesser
B
B
II. Department of Surgery, University of Vienna, Austria.
Hausleithner
V
V
Seitelberger
R
R
Wollenek
G
G
Wolner
E
E
Steiert
H
H
D000255:Adenosine Triphosphate / Q000378:metabolism; D000375:Aging / Q000502:physiology*; D000818:Animals; D006321:Heart / Q000254:growth & development* / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology*; D007036:Hypothermia, Induced; D008955:Models, Cardiovascular; D017202:Myocardial Ischemia / Q000378:metabolism* / Q000503:physiopathology*; D009206:Myocardium / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D011817:Rabbits; D013997:Time Factors
D010725:Phosphocreatine; D000255:Adenosine Triphosphate