Septic cardiomyopathy in critically ill patients

Abstract

Depression of LV intrinsic contractility is constant in patients with septic shock. Because most parameters of cardiac function are strongly dependent on afterload, especially in this context, cardiac performance evaluated at the bedside reflects intrinsic contractility but also thedegree of vasoplegia. Recent advances in echocardiography have allowed better characterization of septic cardiomyopathy. Unlike classic cardiomyopathy, it is not associated with high filling pressures for two reasons: increased LV compliance and frequently associated RV dysfunction. It is always reversible. Although it is unclear how septic cardiomyopathy affects outcome, a hyperkinetic state is indicative of profound and persistent vasoplegia associated with a high mortality rate. Preliminary data suggest that the hemodynamic response to dobutamine challenge has a prognostic value, but large studies are required to establish whether inotropic drugs should be used to treat this septic cardiac dysfunction.

Reversible myocardial depression in patients with septic shock was first described in 1984 by Parker et al. using radionuclide cineangiography. In a series of 20 patients, they reported a 65% incidence of left ventricular(LV) systolic dysfunction, defined by an ejection fraction<45%. In 1990, using transthoracic echocardiography, Jardin et al. reported the same results. In a canine model simulating human septic shock, Natanson et al. demonstrated that intrinsic LV performance was actually depressed in all animals and not corrected by volume expansion. Finally, more recently, Barraud et al. confirmed the presence of severe depressed intrinsic LV contractility using LV pressure/ volume loops in lipopolysaccharide-treated rabbits.

All of these studies, and many others not cited in this introduction, demonstrate the reality of the impairment of intrinsic LV contractility in septic shock. For many years, septic cardiac dysfunction was largely underestimated because the hemodynamic device used, i.e., the pulmonary artery catheter, was not appropriate for establishing such a