Lumb1-4 has demonstrated that gradual occlusion of the coronary arteries in the pig allows nonfunctional collateral vessels to become functional in the ischemic myocardium.
Lumb2 and Garamella5 demonstrated that acute occlusion of the left anterior descending coronary artery in the pig consistently produced ventricular fibrillation within 30 minutes. Our previous data6 confirmed this finding.
Skinner7 demonstrated increased survival of dogs when acute occlusion of the left circumflex coronary artery was supported by mechanical ventricular assistance for five hours. Following acute occlusion of the left anterior descending coronary artery in the pig and ventricular fibrillation, we6 demonstrated that ventricular assistance for three hours allowed all hearts to be defibrillated with survival for 30 to 180 minutes.
This experiment was devised to determine whether six hours of ventricular assistance with the Anstadt Ventricular Assistor8 would allow nonfunctioning coronary collaterals to become functional and increase survival
Hoffer RE, Almond CH, Elefson EE, Corley EA, Kintner LD, Dickhaus DW, Mackenzie JW. Acute Anterior Descending Coronary Artery Ligation, Ventricular Fibrillation, and Ventricular AssistanceSurvival Following These in the Miniature Pig. Arch Surg. 1969;98(6):703-708. doi:10.1001/archsurg.1969.01340120051005