Myocardial ischemia during cardiopulmonary bypass. The hazards of ventricular fibrillation in the presence of a critical coronary stenosis

R. C. Ciardullo, Hartzell V Schaff, J. T. Flaherty, V. L. Gott

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

The effect of a critical coronary artery stenosis on myocardial blood flow and metabolism in the fibrillating heart was assessed by placing 10 dogs on cardiopulmonary bypass, venting the ventricle, inducing ventricular fibrillation, and applying critical stenosis to the left anterior descending coronary artery (LAD). Endocardial and epicardial blood flows were measured by the radioactive microsphere technique prior to the application of the stenosis and after one hour and 2 hours of fibrillation. Intramyocardial oxygen tension (PO2) and carbon dioxide tension (PCO2) were continuously monitored in th LAD-supplied myocardium by a mass spectrometer probe inserted at midmyocardial depth. Selective arterial-coronary venous lactate differences were determined at control, one hour, and 2 hours. At the end of the 2 hour period, vital dye injection defined the distribution of the LAD. Endocardial flow to the myocardium of the stenosed LAD was reduced by 50% after one hour and by 70% after 2 hours (p<0.05). Epicardial flow fell 40 per cent after one hour and 50 per cent after 2 hours (p <0.05). Endocardial and epicardial flow in the distribution of the unstenosed circumflex coronary artery remained unchanged. Changes in myocardial PO2 and PCO2 in the LAD-supplied myocardium indicated the development of severe ischemia in all 10 dogs and suggested myocardial infarction in 5. There was a conversion from lactate extraction to lactate production during the 2 hour period of ventricular fibrillation. From this study, it is concluded tht the myocardium distal to a critical stenosis suffers a progressive reduction in flow during ventricular fibrillation which does not occur in regions supplied by unstenosed coronary arteries. Thus prolonged fibrillation in the presence of a flow-limiting coronary stenosis may play a role in the pathogenesis of myocardial infarction during coronary bypass surgery.

Original languageEnglish (US)
Pages (from-to)746-757
Number of pages12
JournalJournal of Thoracic and Cardiovascular Surgery
Volume73
Issue number5
StatePublished - 1977
Externally publishedYes

Fingerprint

Coronary Stenosis
Ventricular Fibrillation
Cardiopulmonary Bypass
Myocardial Ischemia
Myocardium
Lactic Acid
Coronary Vessels
Pathologic Constriction
Myocardial Infarction
Dogs
Microspheres
Carbon Dioxide
Coloring Agents
Ischemia
Oxygen
Injections

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Surgery

Cite this

Myocardial ischemia during cardiopulmonary bypass. The hazards of ventricular fibrillation in the presence of a critical coronary stenosis. / Ciardullo, R. C.; Schaff, Hartzell V; Flaherty, J. T.; Gott, V. L.

In: Journal of Thoracic and Cardiovascular Surgery, Vol. 73, No. 5, 1977, p. 746-757.

Research output: Contribution to journalArticle

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