Sepsis-Associated Myocardial Dysfunction: Methods

Sepsis-Associated Myocardial Dysfunction: MethodsNonsurvivors had a lower mean systemic vascular resistance index than survivors. Mean stroke volume indexes did not differ between survivors and nonsurvivors. These changes normalized within 10 days after the onset of septic shock. The authors postulated that all patients with septic shock may develop myocardial depression, but nonsurvivors would have a lower systemic vascular resistance index than survivors. They concluded that the lower afterload may result in normal LVEF in nonsurvivors despite a reduced myocardial contractility. Another study by the same group revealed that patients with septic shock, and even those with normotensive sepsis, have a markedly abnormal response in left ventricular stroke work index (LVSWI), which is a measure of external left ventricular work, to volume infusion, indicating that in patients with sepsis an impairment of intrinsic myocardial performance is present. In this study, however, no outcome data are presented; therefore, it remains unknown whether there were any differences in LVSWI between survivors and nonsurvivors, and also whether the previous findings on the prognostic impact of LVEF and systemic vascular resistance index could be confirmed. Similar changes have been observed in the right ventricle (ie, dilatation and reduction of contractility, which are expressed as right ventricular stroke work index). In contrast to the left ventricular pattern, changes in right ventricular performance occurred in both survivors and nonsurvivors, but normalization was seen only in survivors. in detail
In accordance with the results of the study by Parker et al, some studies evaluating cardiac performance in patients with sepsis by echocardiography found an LVEF (using transthoracic echocardiography) or a left ventricular fractional area contraction (LVFAC) [using transesophageal echocardiography] of <50% in approximately 50% of patients with severe sepsis and septic shock. However, the typical pattern of left ventricular dilation in combination with an impaired LVEF was found in only one study, whereas in another study ventricular dimensions were normal despite low LVEF. Many other studies did not report left ventricular dimensions. Very interesting data came from a comprehensive study employing both transesophageal echocardiography and invasive monitoring to assess systolic and diastolic left ventricular function in patients with septic shock. Based on an analysis of transmitral inflow and pulmonary vein flow patterns, patients were subdivided into the following three subsets: (1) ratio of early peak flow velocity to atrial peak flow velocity (E/A) of > 1 and a ratio of systolic to diastolic pulmonary vein flow velocity (S/D) of > 1; (2) E/A of > 1 and S/D of < 1; and (3) E/A of < 1 and S/D of < 1.

This entry was posted in Cardiology and tagged cardiac troponins, myocardial dysfunction, natriuretic peptides, sepsis, septic shock.