CARDIOGENIC SHOCK

✓ Medically ReviewedDISEASEID: MDBT0061🚨 TRIAGE: EMERGENCYICD-10: R57.0

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Definition

CLINICAL DEFINITION

Cardiogenic shock is pump failure causing poor tissue perfusion (low organ blood flow). It needs proven cardiac dysfunction (weak pumping on exam or imaging). It needs hypotension (low pressure) or drugs or devices to hold pressure. Perfusion failure shows as cool clammy skin, low urine or confusion. Labs show high lactate (oxygen debt marker) with low cardiac index (size adjusted output).

IN PLAIN ENGLISH

The heart suddenly pumps too weakly to feed the body. Blood pressure falls and organs get too little blood. Skin turns cold and pale and breathing gets fast. Urine drops and thinking gets foggy. This needs emergency intensive care at once.

COMMON MISCONCEPTION / WHAT IT DOES NOT MEAN

Cardiogenic shock is not low pressure alone without organ injury. It is not faint (brief blackout) that settles lying flat. It is not dehydration alone that corrects fast with fluids. It is not septic vasodilation (infection vessel widening) with a normal pump at first. Diagnosis needs pump failure plus low pressure plus poor flow together.

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Word Breakdown

cardi-

=heart

-genic

=producing or coming from

Literal Meaning: produced by the heart, with shock meaning sudden circulation collapse

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Abbreviations

CS=Cardiogenic shock - pump failure shock with poor organ blood flow

CI=Cardiac index - heart output per minute adjusted for body size

CO=Cardiac output - blood volume pumped per minute

MCS=Mechanical circulatory support - pump devices such as balloon pump or microaxial pump

SCAI=Society for Cardiovascular Angiography and Interventions - body staging shock from at risk to extremis

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Synonyms & Variants

Cardiac shock›Pump failure shock›

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Category-Specific Context

Cardiogenic shock is a Disease because it is a full syndrome (linked set of findings) with causes and course. It sits under Shock with pump failure as the driver. It overlaps infarction (heart attack), heart failure, valve disease and rhythm disease. Care targets the pump cause plus organ support.

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Clinical Context & Usage

CLINICAL SETTINGS

Emergency DepartmentCoronary Care UnitCardiac Intensive Care UnitCardiac Catheterisation LaboratoryPostoperative Cardiac Surgery Unit

USAGE & DOCUMENTATION NOTES

Use the term only when pump failure plus low pressure plus poor flow occur together. Record pressure trend, perfusion signs, lactate (flow marker) and echo (heart ultrasound) findings. State cause such as infarction related or valve related. Add SCAI stage (severity scale) to track path. Reassess often because early shock can mimic simple low pressure.

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Primary Causes & Pathophysiology

PATHOPHYSIOLOGY

Pump injury lowers stroke volume (blood per beat) and cardiac output. Low output drops arterial and coronary pressure (heart vessel flow). Poor coronary flow worsens ischaemia (oxygen shortage) and weakens squeeze further. Vessels tighten and fluid is kept to lift pressure. This raises afterload (pump resistance) and lung pressures. Lungs fill with fluid while organs suffer low flow.

PRIMARY CAUSES

Acute myocardial infarction

Large muscle loss cuts stroke volume (blood per beat) and output. Pressure falls while filling pressures rise. Organs suffer low flow.

Acute decompensated heart failure with low ejection fraction (pump fraction)

Chronic weak pump fails under load or rhythm stress. Forward flow drops while lung and body congestion (fluid buildup) worsen.

Malignant tachyarrhythmia or severe bradycardia (very fast or very slow rhythm)

Extreme rate shortens filling time or cuts beats per minute. Output falls even when muscle strength is intact.

Severe valve lesion such as acute mitral regurgitation (leaky mitral valve) or aortic stenosis (tight aortic valve)

Blocked forward flow or backward leak cuts effective output. Atrial and lung pressures surge while body flow collapses.

Mechanical complications of infarction such as septal rupture (hole between chambers) or papillary muscle rupture

Shunt (abnormal blood diversion) or valve disruption steals forward flow. Filling pressures surge while body output drops.

Acute myocarditis and stress cardiomyopathy (inflammation or temporary ballooning weakness)

Wide inflammation (immune injury) or stunning weakens squeeze across regions. Output drops without blocked arteries.

Post-cardiotomy pump failure after cardiac surgery

Low flow then restored flow injury plus stunning after bypass (heart lung machine use) depresses squeeze. Separation from bypass fails.

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Drug-Induced Causes

💊 Beta-blockers including metoprolol, atenolol and esmolol ↗

Mechanism: Lower squeeze and rate so output and pressure fall, which a failing heart cannot offset

→ Stop drug, monitor rhythm and pressure, use vasopressors (pressure drugs) and inotropes (squeeze drugs), treat slow pulse with atropine or pacing

💊 Non-dihydropyridine calcium channel blockers verapamil and diltiazem ↗

Mechanism: Cut squeeze and slow conduction (electrical spread) with vessel widening, so rate, strength and tone fall together

→ Stop drug, give calcium and cautious fluids, use vasopressors and inotropes, correct salts, involve toxicology early

💊 Antiarrhythmics with negative squeeze effects including flecainide, propafenone and disopyramide ↗

Mechanism: Depress contraction and alter conduction, so weak hearts lose output during rhythm treatment

→ Stop agent, switch to less depressant plan, support pressure, monitor ECG intervals, correct potassium and magnesium

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Epidemiology

Prevalence:Cardiogenic shock is uncommon in the community but central in cardiac intensive care. It complicates a minority of acute infarctions (heart attacks), mainly large anterior events. It appears often in advanced heart failure units. Risk rises with age and coronary burden (artery blockage load).

Age Group:Most cases occur in older adults with coronary disease or chronic failure. Younger cases follow myocarditis (muscle inflammation), overdose, arrhythmia or post-surgical failure. Ischaemic (blocked artery) triggers dominate with age. Inflammatory and toxic triggers dominate in the young.

Geographic Distribution:Cardiogenic shock occurs worldwide wherever coronary disease and heart failure exist. Reported outcomes track access to emergency angioplasty (artery opening), cardiac surgery and mechanical support. Smoking, diabetes and hypertension (high pressure) patterns shape case mix.

Red Flags & Triage ★

TRIAGE LEVEL

🚨 EMERGENCY

DO NOT MISS — LIFE-THREATENING PRESENTATIONS

Coronary occlusion needing emergency artery opening
Septal or papillary muscle rupture needing surgery
Malignant rhythm or complete block needing pacing or shock
Tamponade or massive embolism mimicking pump failure
Mixed septic shock needing antibiotics plus pump support
Beta-blocker or calcium blocker toxicity

URGENT EVALUATION TRIGGERS

Systolic pressure below 90 or support needed to hold pressure
Cold clammy skin with slow colour return
Urine below 30 mL per hour or rising creatinine
New confusion or hard to rouse
Lactate above 2 with acid blood
Lung oedema with low oxygen or oxygen need
Sustained rhythm change, chest pain or arrest

Contraindications & Precautions

CONTRAINDICATIONS

Do not start routine beta-blockers during acute shock with poor flow
Do not delay emergency artery opening for ischaemic cause to try fluids alone
Do not give large fluid boluses in overt lung oedema with high filling pressures

SPECIAL PRECAUTIONS

Give fluids cautiously with lung exam and echo (heart ultrasound) checks
Monitor rhythm always because arrhythmia can start or follow shock
Track kidney function, lactate, urine and alertness hourly early on
Balance bleeding with clotting risk on devices and blood thinners
Search for infection because mixed pump plus septic shock is common

Complications

DOWNSTREAM CLINICAL COMPLICATIONS

Multiorgan failure of kidneys, liver, lungs and brain
Malignant arrhythmia and cardiac arrest
Acute kidney injury needing dialysis
Shock liver from prolonged low flow
Pulmonary oedema with respiratory failure
Limb ischaemia from vasopressors or devices
Bleeding and clotting from devices and anticoagulation
Secondary infection during prolonged intensive care

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Confused With (LASA & DDx) ★

LEXICAL (LASA) — SIMILAR NAMES

Obstructive shock

Shares low output and low pressure but is blocked filling or flow from tamponade (fluid around heart) or lung clot, treated by drainage or clot removal

Septic shock

Shares low pressure and high lactate (flow marker) but is vessel widening from infection, needing antibiotics and source control first

CLINICAL DIFFERENTIAL DIAGNOSES (DDx)

Septic shock

Key Distinguishing Feature: Warm skin early with wide pulse pressure and proven infection source with low vessel tone

Hypovolaemic shock

Key Distinguishing Feature: Flat neck veins with bleeding or fluid loss that lifts with blood or fluids alone

Tamponade with obstructive shock

Key Distinguishing Feature: Pressure dip breathing in with fluid and chamber collapse on echo that eases after drainage

Massive pulmonary embolism

Key Distinguishing Feature: Sudden breathlessness with right heart strain and clot on CT, not left pump failure with lung oedema

Anaphylactic shock

Key Distinguishing Feature: Exposure trigger with hives, swelling and wheeze that responds fast to adrenaline

Neurogenic shock

Key Distinguishing Feature: Spinal injury with warm dry skin and slow pulse from lost nerve tone

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Clinical Pearls

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Check flow not just pressure with mentation, urine, lactate and echo. Near-normal pressure can still hide low output when vessels clamp down.

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Get bedside echo at once to split pump failure from tamponade, valve leak and right heart failure. Each needs a different urgent procedure.

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Open the artery fast when infarction drives shock with cardiology and shock team alert. Artery opening improves survival more than fluids alone.

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Start norepinephrine for low pressure plus dobutamine or milrinone for low output per protocol. Review for mixed vasodilation and infection when pressure stays low.

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Limit fluids when lungs are wet with high filling pressures. Use small fluid tests with lung and echo checks rather than large fixed boluses.

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Example Usage & SOAP

CLINICAL SENTENCE

""68-year-old with anterior infarction developed cold clammy shock with lung oedema needing urgent artery opening.""

IN A SOAP NOTE

S: 68-year-old with chest pressure then severe breathlessness, cold sweats and confusion for 2 hours. O: BP 78/52, HR 118, RR 28, SpO2 88 percent on 4L, Temp 36.1C, cold clammy skin, crackles mid-lungs, raised neck veins, weak pulse, anterior ST elevation, lactate high, echo severe anterior weakness with low pump fraction. A: Cardiogenic shock from infarction with lung oedema and poor flow. P: Emergency cardiology and ICU alert, primary angioplasty plan, norepinephrine plus inotrope per protocol, oxygen, fluid limit, urine and lactate watch, device and surgical backup review.

DIFFERENTIAL DIAGNOSIS CONTEXT

Low pressure with poor flow and pump failure on echo favours cardiogenic shock. Flat veins with bleeding that lifts with fluids favours volume loss. Fever with warm skin and proven infection favours septic shock even when pump function is mildly low.

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Classifications & Scoring

STAGING SCALE

SCAI SHOCK Classification Stages A to E

Stages at risk, beginning, classic, deteriorating and extremis by pressure, flow, drugs and arrest course. Higher stage predicts higher death and guides escalation.

SCORING TOOL

CardShock Risk Score

Predicts short term death using age, confusion, prior infarction, pump fraction, lactate, kidney injury and bedside variables

SCORING TOOL

IABP-SHOCK II Risk Score

Predicts 30-day death in infarction shock using age, prior stroke, glucose, creatinine, lactate and flow after angioplasty

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Prognosis

SHORT-TERM OUTCOME

Short term death stays high in overt shock cohorts despite modern care. Risk rises with high lactate (flow marker), acid blood, cardiac arrest and multi-drug need. Early artery opening for ischaemic cause improves survival. SCAI stage and path predict escalation need.

LONG-TERM PROGNOSIS

Survivors face chronic failure, repeat infarction (heart attack), rhythm disease and readmission. Outlook follows residual pump fraction, complete revascularisation (artery opening) and device harm. Rehab, guideline failure therapy and defibrillator (shock device) review improve course. Some need transplant or durable assist review.

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References & Coding

ICD-10 DIAGNOSTIC CODE

R57.0

LITERATURE CITATIONS & GUIDELINES

[1]ESC Guidelines for heart failure 2021

[2]AHA Scientific Statement on cardiogenic shock

[3]SCAI SHOCK classification expert consensus

MEDICAL DISCLAIMER — This content is intended for educational purposes and qualified healthcare professionals only. Always refer to current clinical diagnostic criteria, institutional protocols, and official guidelines. Medobo is not responsible for clinical decisions made based on this content.