Heart Dysfunction in Human Septic Shock

Although sepsis-induced alteration in cardiac performance is frequent, it is rarely clinically relevant. It occurs within 24 to 48 hours after the onset of sepsis in humans and involves both right and left ventricles. The coexistence of biventricular dilation remains controversial. However, recent data suggest that ventricular dilation is likely related to heavily fluid-resuscitated septic patients. Both reduction in cardiac performance and ventricular dilation recover within 6 to 8 days in septic patients who survive. Despite data suggesting a role for circulating cardiodepressing factors, increasing evidence is in favor of an intrinsic alteration in cardiac myofilament contractile function. Peroxynitrite rather than NO may play a role in this intrinsic alteration. In addition, reduction in myofilament response to calcium also plays an important role in sepsis-induced alteration in cardiac performance. Septic cardiomyopathy rarely needs a specific treatment. Thus, some patients with severe sepsis who do not increase, or who even reduce, cardiac index after adequate volume loading may need inotropic support. This is usually transient in patients who survive.