The Annals of Thoracic Surgery, Vol 55, 946-949, Copyright © 1993 by The Society of Thoracic Surgeons
New experimental technique to study blood cardioplegia in the isolated, perfused rat heart
M Chandra, H Schwalb, E Yaroslavsky-Houminer, Y Appelbaum, G Uretzky and JB Borman
Joseph Lunenfeld Cardiac Surgery Research Center, Hadassah University Hospital, Jerusalem, Israel.
Blood cardioplegia has been extensively studied clinically and in the large
animal experimental model. We describe here a modification of the original
Langendorff technique to study continuous warm blood cardioplegia in the
isolated, perfused rat heart. The excised heart is mounted on the perfusion
apparatus and perfused with Krebs-Henseleit buffer. Prearrest hemodynamics
are recorded. The shed blood in the mediastinal cavity (8 to 12 mL) is
collected, filtered, and reconstituted into cardioplegic solution
(hematocrit, 0.20; K+, 15 mmol/L). Hearts are arrested and maintained at 37
degrees C by continuous recirculation of blood cardioplegia for 1 hour. The
blood cardioplegia system consists of a Silastic tubing oxygenator,
peristaltic pump, and two filters (40 microns pore size). The heart is
reperfused with Krebs-Henseleit solution, and postarrest hemodynamics are
recorded. Percentage recovery of peak left ventricular pressure, heart
rate, and coronary flow were 98.5 +/- 3.1, 102 +/- 4.2, and 98.5 +/- 4.5
(mean +/- standard error of the mean; n = 6), respectively. Myocardial
oxygen consumption during arrest was 57 microL.min-1.g-1 dry wt, which is
10% of the myocardial oxygen consumption of a beating heart in in-vivo and
ex-vivo models. These results suggest the feasibility of studying blood
cardioplegia in the isolated, perfused rat heart model under controlled
conditions. Continuous warm blood cardioplegic arrest provided excellent
myocardial protection for 1 hour in this model.