Overview
Definition
A state of inadequate tissue perfusion due to cardiac dysfunction, resulting in severe hypotension and end-organ damage despite adequate intravascular volume.
Epidemiology
The leading cause of death in patients hospitalized with acute myocardial infarction. Very high mortality rate (40-50%).
Etiology & Risk Factors
- Acute Myocardial Infarction (pump failure - most common)
- Severe Valvular Disease (e.g., acute severe mitral regurgitation from papillary muscle rupture)
- Arrhythmias (prolonged VT or extreme bradycardia)
- Myocarditis / End-stage Cardiomyopathy
Clinical Symptoms
- Severe hypotension (Systolic BP < 90 mmHg)
- Cold, clammy, mottled extremities (poor perfusion)
- Oliguria (decreased urine output)
- Altered mental status / confusion
- Tachycardia and tachypnea
Clinical Approach
Diagnosis
- Echocardiogram (severely depressed LV/RV function, structural defects)
- ECG (evaluate for STEMI/ischemia/arrhythmia)
- Elevated Lactate (tissue hypoperfusion)
- Pulmonary Artery (Swan-Ganz) Catheter (low cardiac index < 2.2, high pulmonary capillary wedge pressure > 15)
Management
- Immediate revascularization (PCI/CABG) if caused by acute MI
- Inotropes (Dobutamine, Milrinone) to increase cardiac contractility
- Vasopressors (Norepinephrine) if severely hypotensive
- Mechanical Circulatory Support (Intra-aortic balloon pump [IABP], Impella, ECMO) as a bridge to recovery or transplant
- Diuretics (only once blood pressure is stabilized, to relieve congestion)
Complications
- Multiple Organ Failure (Renal/Hepatic failure)
- Lethal arrhythmias
- Death