Delayed Recovery Following Hypothermic Arrest in Rabbit Myocardium
The purpose of this investigation was to determine the relationship between the duration of myocardial ischemia at 15°C and the time required for the myocardium to recover maximum contractile function following the ischemia. The isolated blood perfused rabbit heart was used as a model of myocardial ischemia.
Hearts frau 22 New Zealand white rabbits were divided into four groups. In Group I seven hearts were subjected to 15 minutes of ischemia at 15°C. In Group II five hearts were subjected to 30 minutes of ischemia at 15°C. In Groups III and IV the ischemia time was extended to 60 and 120 minutes, respectively. Following the ischemia each heart was reperfused at normothermia and papillary muscle contractility was measured and used as an index of myocardial recovery.
Hearts in Group I recovered their maximum contractile function after an average of 22.5 minutes. Those in Groups II, III, and IV were fully recovered after 31.7, 38.2, and 45.5 minutes, respectively. The study indicates that the time required for the maximum recovery of myocardial contractility following myocardial ischemia increases at a decreasing rate with an increase in the duration of the ischemia at 15°C.
KeywordsCellulose Dioxide Magnesium Ischemia Lactate
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- 1.Angell, W. W., Rikkers, L., Dong, E. Organ Viability with Hypothermia. Journal Thoracic Cardiovascular Surgery 58: 619, 1969Google Scholar
- 4.Engelman, R. M., Chandra, R., Baumann, F. G., and Goldman, R. A. Myocardial reperfusion, a cause of ischemic injury during cardiopulmonary bypass. Surgery 80: 266, 1976.Google Scholar
- 5.Guilbeau, E. J., Fisk, R. L., Gordon, J. P., Edga, S. J., Switzer, A. J., and Moore, L. K. Improved isolated heart contractility with activated carbon hemoperfusion. Trans Am Soc Artif Intern Organs Vol.)XVI: 144, 1980.Google Scholar
- 9.Jennings, R. B. Relationship of accute ischemia to functional defects and irreversability. Circulation 53 (Suppl I): 26, 1976.Google Scholar
- 10.Jennings, R. B. and Ganote, C. E. Structural Changes in Myocardium During Acute Ischemia. Circulation Research Supplement III 34 & 35: 156–168, 1978.Google Scholar
- 13.Malong, J. V., and Nelson, R. L. Myocardial preservation during cardiopulmonary bypass: An overview. J. Thorac Cardiovasc Surg. 68: 101, 1974.Google Scholar
- 15.Reibel, and Rovetto Myocardial ATP Snynthesis and Mechanical Function Following Oxygen Deficiency. American Journal of Physiology 234: H620–H624, 1978.Google Scholar
- 20.Trump, B. F., Mergner, W. J., Kahang, M. W. and Saladino, A. J. Studies on the subcellular pathophysiology of ischemia. Circulation 53 (Suppl I): 14, 1976.Google Scholar
- 21.Tsien, R. W. Possible effect of hydrogen ions in ischEnic myocardium. Circulation 53 (Suppl I): 14, 1976.Google Scholar
- 23.Wakabayashi, A., Mihranian, M., Guilmette, E., Ito, Y. and Connolly, J. E. Functional Evaluation of Normothermic Intermittent Coronary Perfusion. The Journal of Thoracic and Cardiovascular Surgery 75: 20–24, 1978.Google Scholar
- 25.Williamson, J. R., Schaffer, S. W., Ford, C., and Safer, B. Contribution of tissue acidosis to ischenic injury in the perfused rat heart. Circulation 53 (Suppl I): 3, 1976.Google Scholar