Myocardial dysfunction in septic shock

Septic shock is almost uniformly associated with an increased cardiac outpu t and decreased systemic vascular resistance when patients are adequately V olume resuscitated. Despite the increased cardiac output, septic myocardial depression is common. Most patients experience biventricular dilatation, a decrease in ejection fraction, and a depressed Frank-Starling response. In addition, diastolic compliance abnormalities may be seen. These responses may be adaptive and can herald a good outcome. The mechanism underlying sep tic myocardial depression is not myocardial hypoperfusion but rather the di rect cellular effects of circulating or local mediators, particularly the c ytokines TNF-alpha and IL-1 beta. These cytokines may depress baseline and catecholamine stimulated myocardial contractility by a variety of mechanism s. Nitric oxide generation is one such mechanism.