A physiologic explanation for cardiac deterioration in septic shock.

Utilizing analysis of multiple mechanical and electrophysiologic parameters, a technique for describing the myocardial depressant effects of septic shock was employed. Rabbit papillary muscle was exposed to septic shock serum obtained from dogs made hypotensive by infusing Escherichia coli 1-1.9 X 10(9) colony forming units per cubic centimeter (7 cc/kg). The exposure produced depression in action potential amplitude (47%), duration (32%), resting membrane potential (37%), velocities of phases 0 (31%), 2 (100%); phase 3 was preserved. Also, peak tension (62%) and velocity of contraction (51%) and relaxation (56%) were decreased. If the muscle was first exposed to 30 mM KCL solution, these depressions were eliminated. These data suggest the myocardial defects are mediated through abnormalities in fast channel activity.