Heart Dysfunction in Septic Patients: From Physiology to Echocardiographic Patterns

Septic shock represents the vast majority of the cases of shock in intensive care unit (ICU) patients and is a life-threatening condition needing prompt recognition and treatment to provide adequate oxygen utilization to the cells. Initial characterization of sepsis-associated cardiovascular dysfunction was based on clinical patterns identified by physical examination; however, the use of invasive and, more recently, non-invasive tools for hemodynamic assessment at the bedside allowed a more comprehensive evaluation of this clinical condition. The heart is one of the organs most frequently failing in sepsis; however, depending on the definition used, the prevalence of sepsis-induced cardiac dysfunction may vary between 10% and 70%. In this context, several alterations in intracellular signaling pathway mechanisms have been proposed to explain the pathophysiology of septic cardiomyopathy, affecting the cytosolic calcium (Ca2+) and/or myofilament function and cardiac contractile force. Mitochondrial function is also significantly impacted by sepsis. These broad-spectrum micro derangements are associated with even greater variation in macroscopic heart dysfunction patterns, although finding a normal study is not unusual. For this reason, echocardiography plays a pivotal role in septic shock patients, identifying the clinical patterns related to acute right or left ventricular dysfunction. The available literature has shown that diastolic dysfunction and, potentially, right ventricular dysfunction may play a more important role in prognostication of heart damage than acute systolic left ventricular dysfunction, which is quite common, often reversible, and not associated with mortality.