What are the causes of cardiogenic shock in patients with a history of cardiovascular disease, such as coronary artery disease, heart failure, or myocardial infarction?

Causes of Cardiogenic Shock

Primary Etiology

Acute myocardial infarction is the leading cause of cardiogenic shock, complicating 7-10% of AMI cases and requiring loss of at least 40% of left ventricular myocardium to precipitate shock. 1, 2

• AMI-related cardiogenic shock remains the most common cause of mortality in acute myocardial infarction, with 30-day mortality rates of 40-45% despite contemporary treatment advances 1, 3
• The pathophysiology involves extensive myocardial necrosis or stunned but viable myocardium contributing to post-AMI shock 4, 1

Mechanical Complications of Acute Myocardial Infarction

These represent life-threatening causes requiring immediate recognition:

• Left ventricular free wall rupture is the most serious complication following AMI 4, 1
• Ventricular septal rupture creates acute left-to-right shunting with rapid hemodynamic deterioration 1
• Papillary muscle rupture leads to acute severe mitral regurgitation, which is a major predictor of mortality alongside LV ejection fraction 4, 1
• Right ventricular infarction most often associates with inferior AMI, manifesting with RV dyssynergy, dilatation, paradoxical septal motion, and decreased TAPSE 4, 1

Primary Cardiac Dysfunction

Beyond acute ischemia, several cardiac pathologies precipitate cardiogenic shock:

• Acute decompensated heart failure in patients with pre-existing cardiomyopathy can lead to cardiogenic shock, following a more indolent course compared to AMI-related shock 1, 2
• Severe valvular heart disease requiring emergency cardiac surgery 1
• Myocarditis causing acute myocardial inflammation and dysfunction 4, 1
• Myocardial contusion from trauma 4
• Acute aortic dissection with involvement of coronary ostia or acute aortic regurgitation 4

Arrhythmic Causes

Rhythm disturbances can precipitate or complicate cardiogenic shock:

• Atrial fibrillation is present in nearly 20% of cardiogenic shock patients 1
• Severe tachyarrhythmias or bradyarrhythmias causing hemodynamic compromise 1
• Conduction disorders associated with hemodynamic instability 1

Critical Diagnostic Approach

When evaluating suspected cardiogenic shock, immediate echocardiography is essential:

• Perform immediate transthoracic echocardiography to confirm the diagnosis, identify the specific cause, assess hemodynamic status including filling pressures and stroke volume, and rule out other shock etiologies 4
• If TTE is suboptimal, proceed directly to transesophageal echocardiography 4
• Look specifically for depressed LV global function (ejection fraction), regional wall motion abnormalities, decreased stroke volume and cardiac output, elevated LV filling pressures, and secondary mitral regurgitation 4

Common Pitfalls in Diagnosis

Avoid confusing late-stage septic shock with cardiogenic shock—septic shock can develop myocardial depression, but the primary hemodynamic pattern remains distributive with decreased systemic vascular resistance, whereas cardiogenic shock demonstrates elevated SVR as a compensatory mechanism 5

• When diagnosis remains unclear after echocardiography, invasive hemodynamic monitoring with pulmonary artery catheterization provides definitive measurements: cardiac index <2.2 L/min/m², PCWP >15 mmHg, CVP >15 mmHg, and elevated SVR 1, 5
• In RV infarction, assessment of LV function can be challenging as the LV may be relatively unloaded; when considering mechanical support, increased volume delivered to the LV by an RVAD may reveal significant LV dysfunction 4