Septic cardiomyopathy

Abstract

Depression of left ventricular (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, the cardiac performance evaluated at the bedside reflects intrinsic contractility, but also the degree of vasoplegia. Recent advances in echocardiography have allowed better characterization of septic cardiomyopathy. It is always reversible providing the patient's recovery. Unlike classic cardiomyopathy, it is not associated with high filling pressures, for two reasons: improvement in LV compliance and associated right ventricular dysfunction. Although, it is unclear to which extent it affects prognosis, a hyperkinetic state is indicative of a profound and persistent vasoplegia associated with a high mortality rate. Preliminary data suggest that the hemodynamic response to a 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.

Figure 1

Transesophageal echocardiography in two patients--one with cardiogenic shock (above) and the other with septic shock (below). In the patient with cardiogenic shock, the left ventricular short-axis view demonstrated global hypokinesia of the left ventricle with major dilatation. Pulsed Doppler at the mitral valve demonstrated a restrictive pattern of the left ventricular inflow with a high E wave velocity and a very low A wave velocity, highly suggestive of a high LV filling pressure. Note also the thrombus in the left ventricle (arrow). In the patient with septic shock, the short-axis view also demonstrated global hypokinesia of the left ventricle, but without a major dilatation. Note also the Doppler profile at the mitral valve, highly suggestive of normal LV filling pressure.

Figure 2

Long-axis view of the left ventricle by a transesophageal approach in a patient ventilated for septic shock. At day 1 (panel A), the patient had right ventricular dysfunction illustrated by major dilatation of the right ventricle. At day 2 (panel B), this was corrected. RV, right ventricle; LV, left ventricle.

Figure 3

Short-axis view of the left ventricle by a transgastric approach in a patient with septic shock at baseline after initial resuscitation and after a few hours of norepinephrine infusion. Note that restoration of a "normal" left ventricular afterload has unmasked impaired contractility. LVEF, left ventricular ejection fraction.

Figure 4

Relationship between left ventricular (LV) ejection fraction (x axis) and cardiac index (y axis) in 183 patients with septic shock who underwent echocardiography. Providing that depressed LV intrinsic contractility is constant, the relation may be separated into four parts according to systemic vascular resistance, volemia, and right ventricular (RV) function. Size of the circles is related to LV end-diastolic volume, from 35 for the smallest to 135 ml for the biggest.