Preservation of myocardial ultrastructure after 24 hours of Klebsiella sepsis: histologic, functional, and biochemical correlations.

Myocardial function with ultrastructure and high energy phosphate levels in dogs was correlated after 24 hours of sepsis using live Klebsiella aerogenes. All animals developed progressive hemodynamic deterioration over a 24 hour period. Mean arterial pressure decreased from 148 +/- 7 mmHg to 85 (P less than 0.01) and cardiac output decreased from 3.43 +/- .31 to 1.6 +/- 0.5 L/min. Left ventricular stroke work decreased from 48.2 +/- 5 to 18.1 +/- 6 gm-meters (P less than 0.001). Systemic and pulmonary vascular resistances were increased at 24 hours (3,538 +/- 27 to 7,404 +/- 1,400 dyne/sec/cm-5 (P less than 0.01), and 185 +/- 20 and 619 +/- 90 dyne/sec/cm-5 (P less than 0.001), respectively. Left ventricular function curves at 24 hours showed a fixed low output. However, myocardial ultrastructure was preserved and high energy phosphate levels remained normal. These observations correlate well with the changes seen clinically in early gram negative sepsis in hypovolemic patients. Thus, this appears to be a suitable model for further investigation of the effects of gram negative sepsis on myocardial performance, ultrastructure, and maintenance of energy stores.