Myocardial Dysfunction and Shock after Cardiac Arrest

Abstract

Postarrest myocardial dysfunction includes the development of low cardiac output or ventricular systolic or diastolic dysfunction after cardiac arrest. Impaired left ventricular systolic function is reported in nearly two-thirds of patients resuscitated after cardiac arrest. Hypotension and shock requiring vasopressor support are similarly common after cardiac arrest. Whereas shock requiring vasopressor support is consistently associated with an adverse outcome after cardiac arrest, the association between myocardial dysfunction and outcomes is less clear. Myocardial dysfunction and shock after cardiac arrest develop as the result of preexisting cardiac pathology with multiple superimposed insults from resuscitation. The pathophysiology involves cardiovascular ischemia/reperfusion injury and cardiovascular toxicity from excessive levels of inflammatory cytokine activation and catecholamines, among other contributing factors. Similar mechanisms occur in myocardial dysfunction after cardiopulmonary bypass, in sepsis, and in stress-induced cardiomyopathy. Hemodynamic stabilization after resuscitation from cardiac arrest involves restoration of preload, vasopressors to support arterial pressure, and inotropic support if needed to reverse the effects of myocardial dysfunction and improve systemic perfusion. Further research is needed to define the role of postarrest myocardial dysfunction on cardiac arrest outcomes and identify therapeutic strategies.

Figure 1

Pathophysiologic mechanisms involved in postarrest myocardial dysfunction. Boxes represent major contributing etiologies. Circles represent therapeutic interventions explored in experimental models of cardiac arrest.

Figure 2

Suggested early goal-directed hemodynamic optimization strategy for patients with hypotension or hypoperfusion after return of spontaneous circulation following cardiac arrest. CVP, central venous pressure; PPV, pulse pressure variation; SVV, stroke volume variation; IVC, inferior vena cava; MAP, mean arterial pressure; HR, heart rate; S_cvO₂, central venous oxygen saturation; CO, cardiac output.