Cardiogenic shock after acute coronary occlusion. Pathogenesis, early diagnosis, and treatment

The early natural history of left anterior descending coronary artery (LAD) occlusion and the development of cardiogenic shock was studied in 35 open chest anesthetized dogs observed for 6 hours. Six control dogs underwent LAD isolation without occlusion, 13 underwent isolated LAD occlusion to simulate single vessel disease, and 14 underwent LAD occlusion and a 50% left circumflex coronary artery (LCA) stenosis to stimulate multi-vessel disease. Control dogs undergoing anesthesia showed no significant changes in hemodynamics after 6 hours. All dogs with single vessel disease survived and developed immediate and persistent dyskinesis of the anterior wall, a compensatory hypercontractility of remote muscle (131% of control)*, slight energy and substrate depletion and anaerobic metabolism (increased G6P)* despite maintenance of "normal" blood flow through the LCA. In contrast, early mortality was 57% in simulated multi-vessel disease as intractable ventricular fibrillation and/or cardiogenic shock caused the deaths of 7 of 13 dogs (57%)*. Remote muscle became progressively hypocontractile (61% of control)* and caused progressive reduction in stroke work index (less than or equal to 0.5 g x m/kg)*. Remote muscle showed moderate substrate and energy depletion (greater than or equal to 60% fall of ATP and CP, 37% fall of glutamate)* and more pronounced evidence of anaerobic metabolism (G6P rose 373%)* despite "normal" blood flow. These findings suggest that remote muscle is the principle determinant of mortality after an otherwise non-lethal cardiac event.(ABSTRACT TRUNCATED AT 250 WORDS)