Cardiovascular · Topic 10 of 48

Cardiogenic Shock

Cardiovascular · shock

Cardiogenic Shock

Pump failure with hypoperfusion. Stage it (SCAI A–E), support with norepinephrine and an inotrope, revascularize the culprit artery, and escalate early.

Key numbers

Hypotension plus hypoperfusion from heart failureSBP < 90 mmHg > 30 min

Cardiac index < 2.2, wedge > 15CI < 2.2 L/min/m²

Target MAP above 60–65 mmHgMAP > 60–65 mmHg

01 · Defined byHypotension plus hypoperfusion from heart failure

Cardiac cause plus SBP < 90 mmHg (or MAP < 60) for over 30 minutes or vasopressors needed, plus hypoperfusion: altered mentation, cold extremities, urine < 30 mL/h or lactate > 2 mmol/L.

02 · Defined byCardiac index < 2.2, wedge > 15

Hemodynamic profile of cardiogenic shock: cardiac index below 2.2 L/min/m² with pulmonary capillary wedge pressure above 15 mmHg — the cold-and-wet profile.

03 · DoMI shock: revascularize the culprit artery

In MI-related shock, emergent angiography and revascularization of the culprit vessel (PCI, or CABG if PCI is not feasible) is the definitive treatment; PCI of non-culprit stenoses is deferred.

Presentation

What you'll see

Shock can be normotensiveHypoperfusion without hypotension still counts and carries high mortality: watch for narrow pulse pressure (< 25% of SBP), heart rate > 100, cool clammy skin, capillary refill > 2 seconds and falling urine output.

Diagnosis & monitoring

Work-up

SCAI stages A to E must knowSCAI stages: A at risk; B beginning shock (hypotension or tachycardia without hypoperfusion); C classic shock with hypoperfusion; D deteriorating despite escalating drugs or devices; E extremis (refractory shock, cardiac arrest, ongoing CPR).

Target MAP above 60–65 mmHgTitrate vasoactive support to a MAP above 60–65 mmHg while restoring end-organ perfusion (mentation, urine output, lactate).

Do right now

In this order

First moves

Hypotension plus hypoperfusion from heart failureSBP < 90 mmHg > 30 min

→

ECG and echo in every suspected case

→

Norepinephrine first for hypotension

→

MI shock: revascularize the culprit artery

→

Microaxial pump for selected STEMI shock

Why each step

Hypotension plus hypoperfusion from heart failureCardiac cause plus SBP < 90 mmHg (or MAP < 60) for over 30 minutes or vasopressors needed, plus hypoperfusion: altered mentation, cold extremities, urine < 30 mL/h or lactate > 2 mmol/L.

ECG and echo in every suspected caseGet a 12-lead ECG and an echocardiogram or point-of-care ultrasound in every suspected case: ST elevation goes to the cath lab; echo finds LV or RV failure, tamponade, acute valve lesions or mechanical complications.

Norepinephrine first for hypotensionNorepinephrine, an inopressor (α1 > β1; raises SVR and blood pressure; 0.05–1 mcg/kg/min), is the first-line vasoactive for hypotensive cardiogenic shock; use the lowest dose for the shortest time.

MI shock: revascularize the culprit arteryIn MI-related shock, emergent angiography and revascularization of the culprit vessel (PCI, or CABG if PCI is not feasible) is the definitive treatment; PCI of non-culprit stenoses is deferred.

Microaxial pump for selected STEMI shockA microaxial flow pump (Impella CP) is reasonable (Class 2a) in selected STEMI-related shock with LV-dominant failure — DanGer Shock cut 6-month mortality from 58.5% to 45.8%, with more bleeding and limb ischemia.

Management

Orders

Add an inodilator: dobutamine or milrinoneInodilators raise output and lower SVR, suiting low output with adequate blood pressure: dobutamine (β1 > β2, 2–10 mcg/kg/min) or milrinone (PDE-3 inhibitor; renally cleared, long-acting — caution as renal function worsens).

Escalate to mechanical support if drugs failWhen end-organ function cannot be maintained with drugs, temporary mechanical circulatory support is reasonable (Class 2a); contact a Level 1 shock center early and transfer refractory patients.

PA catheter defines LV, RV or biventricular shockA pulmonary artery catheter may be considered (Class 2b): LV-dominant shock has PCWP > 15 mmHg; RV-dominant shock has right atrial pressure > 15 mmHg with a relatively normal wedge.

Use a multidisciplinary shock teamManagement by a multidisciplinary shock team (critical care cardiology, advanced HF, interventional cardiology, cardiac surgery) is reasonable (Class 2a) and associated with lower mortality.

Red flags & don'ts

Avoid harm

Avoid phenylephrine as the only pressor avoidA pure vasoconstrictor such as phenylephrine causes reflex bradycardia and lowers cardiac output; it is strongly discouraged as the single first-line agent in cardiogenic shock.

No routine IABP or VA-ECMO in MI shock avoidRoutine IABP (IABP-SHOCK II) and early routine VA-ECMO (ECLS-SHOCK) did not lower mortality in MI-related shock; the 2025 ACS guideline rates routine use Class 3: No Benefit.

Norepinephrine or dobutamine?

Commonly confused

Class	Inopressor
Receptors	α1 strongest, then β1
Vascular resistance	Raises SVR
Best fit	Hypotensive cardiogenic shock — first choice
Usual dose	0.05–1 mcg/kg/min

More detail

Reference

Show 6 reference facts

Cardiogenic shock carries 30–40% short-term and about 50% 1-year mortality; it complicates 5–10% of acute MIs.

Cardiac power output = MAP × cardiac output / 451; ≤ 0.6 W marks classic (SCAI C) shock. A low pulmonary artery pulsatility index (PAPi) signals RV failure.

Most patients change SCAI stage within the first 24 hours (stage B most often worsens); check lactate, pH, creatinine and liver tests every 2–4 hours early, and consider a daily echo.

Causes split into MI-related shock and HF-related shock (de novo, such as myocarditis or takotsubo, or acute-on-chronic); HF-related shock is now increasingly common.

IV beta-blockers early in MI increase the risk of cardiogenic shock; oral beta-blockers are started only when there is no heart failure or hypotension.

Treat congestion with IV loop diuretics, adding a thiazide or ultrafiltration if refractory; positive-pressure ventilation lowers LV afterload and helps LV failure but can worsen RV failure.

Pearl

Cold, wet and low: cardiac index under 2.2 with a wedge over 15 — open the artery and support the pump before the organs fail.

Sources · Heidenreich PA et al. 2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure (§9.5 cardiogenic shock; Tables 22–24). J Am Coll Cardiol 2022;79:e263–e421 · Sinha SS et al. 2025 Concise Clinical Guidance: ACC Expert Consensus Statement on the Evaluation and Management of Cardiogenic Shock. J Am Coll Cardiol 2025;85:1618–1641 · ACC — Cardiogenic Shock and Mechanical Circulatory Support: Year in Review 2025 · Merck Manual Professional — Complications of Acute Coronary Syndromes · ACC Clinical Trial Summary — DanGer Shock (Microaxial Flow Pump in Infarct-Related Cardiogenic Shock) · Left Ventricular Mechanical Circulatory Support Devices for Cardiogenic Shock After Myocardial Infarction. Cardiol Ther 2025 (SCAI stage criteria table) · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).