CardiogenicShock

Cardiogenic shock · complete reference · all trials · full doses + brand names · SCAI staging · Full Card

Symptoms / Associated Sx

• Classic triad: hypotension (SBP <90 mmHg or ≥30 mmHg drop from baseline), end-organ hypoperfusion (AMS, oliguria UO <0.5 mL/kg/hr, rising lactate), elevated filling pressures (JVD, crackles, S3, pulmonary edema)

• Cool, clammy, mottled extremities; diaphoresis; pallor; narrow pulse pressure (<25 mmHg — reflects ↓stroke volume); tachycardia (compensatory — may be absent in BB-treated patients or AV block); altered mental status (confusion → somnolence → coma)

• Signs localizing the cause: S3 + bibasilar crackles + JVD = ADHF-CS; new holosystolic murmur at apex (papillary muscle rupture — acute MR) or left sternal border (VSD — post-MI Day 3–7); Beck triad (JVD + hypotension + muffled heart sounds) = tamponade; JVD + clear lungs + inferior STE = RV MI; RV failure without MI = massive PE or pulmonary HTN crisis

• SCAI Shock Classification: Stage A = at-risk (no hemodynamic compromise, biomarkers ↑); Stage B = beginning shock (tachycardia + ↑filling, SBP OK); Stage C = classic cardiogenic shock (SBP <90 + MAP <65 + tissue hypoperfusion); Stage D = deteriorating (worsening despite initial therapy); Stage E = extremis (cardiac arrest, CPR/MCS required); mortality Stage C ~30%, Stage E >50%

Neg

• Pt denies fever + warm flushed vasodilated skin + bounding pulses + high WBC with differential shift + obvious infection source in context of hypotension — argues against septic shock (septic/distributive shock: ↑CO + ↓SVR on echo/Swan-Ganz; hyperdynamic LV; management = IVF bolus 30 mL/kg + norepinephrine [Levophed] + antibiotics; inotropes not first-line; echo distinguishes: ↑CO in sepsis vs ↓CO in cardiogenic)

• Pt denies significant volume depletion history (GI losses, hemorrhage, third-spacing) with flat neck veins, dry mucous membranes, and empty LV on echo (hyperdynamic, small cavity) — argues against hypovolemic shock (fluid challenge 500 mL IVF bolus → if CO improves → hypovolemic; do NOT diurese a hypotensive patient without confirming elevated filling pressures first)

• Pt denies absent or markedly diminished unilateral breath sounds with tracheal deviation away from silent side and JVD without cardiac cause — argues against tension pneumothorax (obstructive shock — needle decompression 2nd intercostal space MCL immediately BEFORE any other intervention; do NOT obtain CXR if tension pneumothorax is hemodynamic emergency)

• Pt denies massive PE signs (RV dilation + RV hypokinesis + McConnell sign on echo without LV WMA, CT-PA positive) without LV dysfunction — argues against obstructive/PE-mediated shock (management = IV heparin + systemic tPA [alteplase 100 mg IV over 2h] if hemodynamic collapse; catheter-directed tPA for submassive PE; NOT inotropes first)

Social History (SHx)

• Recent STEMI/NSTEMI (timing, vessel, revascularization status — unrevascularized proximal LAD STEMI = highest risk); prior HF and last known EF; prior cath anatomy (multivessel CAD significantly ↑CS risk); prior LVAD or transplant evaluation status; prior ICD interrogation (recent appropriate shocks = arrhythmia-mediated CS)

• Time course of deterioration (abrupt = mechanical complication [papillary rupture, VSD, free wall rupture] — Days 3–7 post-MI; gradual = ADHF decompensation progressing to CS); current medications including BB (negative inotropy ↑CS risk), GDMT doses; recent changes in antihypertensives or GDMT

Main Etiology

• Acute MI-related (80%): large anterior STEMI (LAD territory) = most common single etiology; multivessel STEMI; mechanical complications post-MI (papillary muscle rupture → acute severe MR; VSD → biventricular failure; free wall rupture → tamponade); RV MI (complicates 30–50% of inferior STEMI); failed or delayed reperfusion

• Non-MI cardiac causes: end-stage decompensated HFrEF (Forrester Class IV — cold+wet); fulminant myocarditis (giant cell myocarditis — rapidly fatal without cardiac support; endomyocardial biopsy ±; immunosuppression for GCM); Takotsubo CM (catecholamine surge — avoid inotropes; IABP preferred; recovers); acute severe valvular dysfunction (acute AR from endocarditis/aortic dissection; acute MR from chord rupture; critical AS); massive PE (obstructive); cardiac tamponade (obstructive)

• Arrhythmia-mediated: VT storm (rapid VT → ↓CO → shock); complete AV block with bradycardia; AF-RVR in severe HF (rate-mediated ↓diastolic filling → ↓CO)

RF

• Large anterior STEMI (LAD/proximal LAD — largest territory at risk); multivessel CAD (prior MI + reduced EF = severely limited cardiac reserve); mechanical complication development (Days 3–7 post-STEMI: new systolic murmur = emergency echo); end-stage HFrEF (EF <20% = very limited reserve); fulminant myocarditis (any age — giant cell myocarditis lethal within weeks without advanced support); cardiac tamponade (malignancy, TB pericarditis, uremia, hemorrhagic)

Data

• Bedside echo — STAT, before any treatment decision (EF: global vs regional dysfunction [ischemic = regional; Takotsubo = apical; sepsis = global]; LV size: dilated = ADHF-CS; small/hyperdynamic = hypovolemic shock; RV: dilated + hypokinetic = PE or RV MI or pulmonary HTN crisis; tamponade: pericardial effusion + RV diastolic collapse + IVC plethora ≥21 mm with <50% inspiratory collapse; mechanical: severe MR on color Doppler; VSD — systolic flow jet at interventricular septum; IVC size — volume estimate)

• ECG STAT (STEMI/equivalent → cath lab immediately; VT/VF; complete AV block [inferior MI: usually transient]; new LBBB; tachyarrhythmia-mediated CS; compare to prior ECG)

• Lactate serial q4–6h (tissue hypoperfusion: >2 mmol/L = shock; >4 = profound; clearance at 4–6h: target ≥10%/h improvement; failure to clear = inadequate resuscitation → ↑MCS; serial lactate is the single best bedside monitor of shock adequacy)

• Right heart catheterization (Swan-Ganz catheter) (gold standard confirmation: CI <2.2 L/min/m2 = low CO; PCWP >18 mmHg = elevated filling pressures; SvO2 <65% = ↑O2 extraction ratio from ↓CO; confirms CS diagnosis; guides vasopressor + inotrope titration; identifies subtype: LV failure vs RV failure vs biventricular failure; CI + SvO2 guide MCS level of support)

• BMP q6–8h (Cr — AKI is primary end-organ marker of shock; rising Cr = progressive organ failure; K+ ≥5.0 = ↑VF risk in ischemic myocardium; CO2 ↓ = metabolic acidosis from poor perfusion; Na+ <130 = neurohormonal activation + poor prognosis in HF-CS)

• Troponin serial (peak value correlates with infarct size; re-elevation = reinfarction or stent thrombosis → urgent repeat PCI)

• CBC (Hgb — anemia ↑demand ischemia; transfuse to Hgb ≥8–10 in CS; WBC — infection trigger; eosinophilia suggests eosinophilic myocarditis [steroids])

• Coagulation studies + T&S (DIC from prolonged hypoperfusion — fibrinogen, D-dimer, PT/PTT; 2 units pRBC on hold for all CS patients; anti-Xa if on LMWH)

• CXR portable (pulmonary edema Killip ≥3; cardiomegaly; pneumothorax — tension; mediastinal widening — dissection/tamponade)

• BNP or NT-proBNP (elevated in LV failure CS; less elevated in RV failure or obstructive shock; guides diuretic timing post-stabilization)

• ABG (metabolic acidosis [↓pH, ↓HCO3, ↓pCO2 compensatory] = tissue hypoperfusion; hypoxemia [↓pO2] = pulmonary edema; respiratory failure → intubation threshold)

DDx

Septic shock (warm + vasodilated + febrile + ↑WBC + ↑CO on echo/Swan — IVF + norepinephrine [Levophed] + antibiotics; NOT inotropes-first; echo distinguishes: ↑CO in sepsis vs ↓CO in cardiogenic) · Hypovolemic shock (volume depletion history + flat JVP + small/empty LV + hyperdynamic echo — IVF bolus 500 mL; do NOT diurese) · Tension pneumothorax (absent unilateral BS + tracheal deviation + JVD — needle decompression 2nd ICS MCL immediately before CXR) · Massive PE/obstructive shock (RV dilation + RV hypokinesis + McConnell + CT-PA — anticoag + tPA if hemodynamic collapse; NOT inotropes) · Cardiac tamponade (Beck triad + pulsus paradoxus >10 + RV diastolic collapse on echo — pericardiocentesis NOW) · Severe ADHF (Forrester III) (cold+wet but not hypotensive — no shock yet; treat with diuresis + vasodilators + inotrope; different from CS)

Home Meds

• Hold in active cardiogenic shock: BB (carvedilol [Coreg]/metoprolol succinate [Toprol-XL]) — negative inotropy worsens low CO; hold or ↓50% if HR <60 or SBP <85; DO NOT stop abruptly — rebound ischemia risk; taper if possible; ACEi/ARB (↓afterload theoretically OK but ↑AKI + ↑K+ in shock — hold until hemodynamically stable); MRA (spironolactone [Aldactone]/eplerenone [Inspra]) — ↑K+ + ↑AKI risk; SGLT2i (Farxiga/Jardiance) — hold if hemodynamically unstable or eGFR <20

• Continue with caution: aspirin (Bayer) 81 mg PO daily (continue for ACS-CS); atorvastatin (Lipitor) 80 mg PO daily; antiarrhythmics if prescribed (amiodarone [Pacerone] — check level; avoid in torsades)

• Vasopressors + inotropes override all home medications in hemodynamically unstable cardiogenic shock; restart GDMT during recovery phase once hemodynamically stable off vasopressors

Plan

• Step 1 — Identify the cause using bedside echo (determines ALL management decisions):

  • LV failure (↓EF + dilated/hypokinetic LV) → inotropes + MCS + address cause (revascularization if STEMI)

  • RV failure (dilated + hypokinetic RV, preserved LV) → IV fluids + vasopressin (Pitressin) + avoid diuretics + treat cause (RV MI → reperfusion; PE → anticoag ± tPA)

  • Tamponade (pericardial effusion + RV diastolic collapse + IVC plethora) → pericardiocentesis IMMEDIATELY before any other intervention

  • Mechanical complication (severe MR on color Doppler; VSD jet) → emergent cardiothoracic surgery + IABP bridge

  • Hyperdynamic empty LV → reconsider diagnosis (hypovolemic? distributive? not cardiogenic)

• Step 2 — CCU transfer immediately: ICU/CCU team; arterial line (radial preferred — real-time continuous BP); central venous access (internal jugular or subclavian); Foley (UO monitoring q1h); continuous cardiac monitor + pulse oximetry; consider Swan-Ganz catheter for hemodynamic guidance in complex/refractory CS

• Step 3 — Vasopressors (MAP <65 or SBP <90):

  • Norepinephrine (Levophed) 0.01–0.5 mcg/kg/min IV first-line (SOAP II 2010: ↓arrhythmia vs dopamine [Intropin]; preferred for all types of shock; ↑SVR + mild ↑CO via beta-1)

  • Vasopressin (Pitressin) 0.03–0.04 units/min (fixed dose; add-on for refractory shock; preferred for RV failure — ↑SVR without ↑pulmonary vascular resistance; does not ↑myocardial O2 demand)

  • Dopamine (Intropin) 5–20 mcg/kg/min (second-line — SOAP II: ↑atrial arrhythmia risk; use if bradycardia component; dose-dependent: 1–3 mcg/kg/min = "renal dose" [minimal hemodynamic effect]; 3–10 = beta-dominant; >10 = alpha-dominant)

  • Epinephrine (Adrenalin) 0.01–0.5 mcg/kg/min (potent alpha + beta; preferred in cardiac arrest post-ROSC with shock; ↑arrhythmia risk; ↑myocardial O2 demand)

• Step 4 — Inotropes (confirmed ↓CO, CI <2.2 on echo or Swan-Ganz):

  • Dobutamine (Dobutrex) 2–20 mcg/kg/min IV (primary inotrope in CS — ↑CO via beta-1; ↓SVR [↓afterload]; ↑arrhythmia risk; tachyphylaxis at 72h; avoid if BP <75 without concurrent vasopressor)

  • Milrinone (Primacor) 0.1–0.75 mcg/kg/min IV (PDE3 inhibitor — ↑CO + ↓SVR + ↓PVR; preferred in BB-treated patients [bypasses beta-receptor]; preferred in RV failure [↓PVR]; reduce 50% if CrCl <30; vasodilatory — use with vasopressor if hypotensive)

  • Levosimendan (Simdax): calcium sensitizer — not widely available in US; used in Europe for CS bridge; improve responsiveness without increasing O2 demand

• Step 5 — MCS escalation (SCAI Stage C or D not improving on vasopressor + inotrope within 30–60 min):

  • Impella CP (Abiomed): axial flow pump; provides up to 3.5 L/min CO support; FDA-approved for CS; placed percutaneously via femoral artery across aortic valve into LV; unloads LV; preferred for isolated LV failure; IABP-SHOCK II (2012, NEJM): IABP does NOT ↓30-day mortality vs medical therapy in STEMI-CS; Impella hemodynamically superior to IABP

  • IABP (Datascope): intra-aortic balloon pump; counterpulsation — ↑diastolic BP + ↓afterload; limited CO support (~0.5 L/min); bridge to surgery or decision; most commonly used in mechanical complications (papillary rupture, VSD) pre-surgery

  • VA-ECMO (venoarterial extracorporeal membrane oxygenation): full biventricular support + oxygenation; femoral arterial + femoral venous cannulation; provides 3.5–6 L/min support; indicated for biventricular failure, cardiac arrest with ECPR, massive PE; increases LV afterload → LV distension (↑LVEDP) — may need concurrent Impella ("ECPella") to vent LV; highest-risk procedure, highest-morbidity support

  • Impella RP (Abiomed) or TandemHeart: RV assist device; for isolated RV failure not responding to vasopressin + fluids

  • Timing principle: early MCS (SCAI Stage C) significantly better outcomes than rescue MCS (Stage E); escalate proactively before multi-organ failure, not reactively after

• STEMI + cardiogenic shock — immediate PCI:

  • Cath lab activation immediately regardless of time from onset (SHOCK trial 1999, NEJM: early revascularization ↓1-year mortality 46.7% vs 63.1%; NNT 8; benefit greatest >54 years; continues at 6 years)

  • CULPRIT-SHOCK trial (2017, NEJM): PCI of culprit vessel only at time of STEMI + shock → ↓30-day death/RRT vs multivessel PCI (45.9% vs 55.4%; NNT 10); staged non-culprit PCI later when hemodynamically stable; do NOT perform complete revascularization in acute STEMI + CS

  • Impella CP (Abiomed) insertion before or at time of PCI in STEMI-CS; "Impella first" approach increasingly adopted

• Cardiac tamponade: pericardiocentesis under echo guidance immediately; subxiphoid or apical approach; drain minimum volume for hemodynamic stability; leave drainage catheter in place; send fluid for cytology + cultures + protein + LDH + glucose; pericardial window for malignant or recurrent effusion

• Mechanical complications (papillary rupture/VSD):

  • IABP (Datascope) or Impella CP (Abiomed) bridge immediately

  • Emergent cardiothoracic surgery for papillary muscle rupture (MV repair preferred over replacement) + VSD repair

  • Stabilize hemodynamics with MCS before OR; longer wait = higher pre-op mortality; timing requires judgment — CS specialist + cardiac surgery

• Fulminant myocarditis: MCS (Impella CP [Abiomed] or VA-ECMO) bridge; endomyocardial biopsy (giant cell myocarditis: multi-nucleated giant cells → immediate immunosuppression — methylprednisolone 1 mg/kg/day + cyclosporine [Sandimmune] 5 mg/kg/day; eosinophilic myocarditis → steroids; lymphocytic → supportive); transplant evaluation if refractory

• Post-shock recovery GDMT restart: once off vasopressors and MAP ≥65 without support — gradually restart: low-dose carvedilol (Coreg) 3.125 mg PO BID + sacubitril/valsartan (Entresto) 24/26 mg PO BID + spironolactone (Aldactone) 25 mg PO daily + dapagliflozin (Farxiga) 10 mg PO daily; wean inotropes slowly; reassess EF at 3 months

• PT/OT eval and treat — not active during shock; reassess when vasopressors weaned and hemodynamically stable; ICU deconditioning protocol; early PT/OT once transferred out of CCU; advance care planning if refractory CS

• Trend (every hour in active CS): arterial BP continuous; HR; UO q1h (target ≥0.5 mL/kg/hr); SpO2 continuous; lactate q4–6h (target clearance ≥10%/h, <2 mmol/L); CI (Swan) target >2.2; PCWP target 15–18; SvO2 target >65%; BMP q6–8h (K+/Cr/CO2/glucose); CBC; troponin serial (re-elevation = stent thrombosis → repeat PCI); temperature curve; ABG q4–6h; ventilator settings if intubated; Impella or VA-ECMO parameters if MCS in place

• Escalation triggers: SCAI Stage C → D (MAP ↓ despite vasopressors + inotropes, lactate rising, UO <0.3 mL/kg/hr) → upgrade MCS: Impella CP (Abiomed) → Impella 5.5 or VA-ECMO · refractory VT/VF → amiodarone (Pacerone) 150 mg IV → 1 mg/min ×6h + defibrillation; lidocaine (Xylocaine) 1–1.5 mg/kg IV bolus for refractory VT · complete AV block + hemodynamic instability → transcutaneous → transvenous temporary pacing; permanent PPM only after 2 weeks post-MI (inferior MI — usually transient) · worsening multi-organ failure (MSOF: Cr >3, bilirubin >3, GCS <12) → CRRT + advanced care planning discussion + palliative care team · refractory cardiogenic shock without reversible cause → transplant listing or permanent LVAD (HeartMate 3 [Abbott]) evaluation + advanced HF team

• Discharge (if survived to hemodynamic recovery): comprehensive GDMT: sacubitril/valsartan (Entresto) 24/26→97/103 mg PO BID + carvedilol (Coreg) 3.125→25 mg PO BID or metoprolol succinate (Toprol-XL) 12.5→200 mg PO daily + spironolactone (Aldactone) 25→50 mg PO daily + dapagliflozin (Farxiga) 10 mg PO daily; ferric carboxymaltose (Injectafer) if Fe deficient; ICD evaluation at 40 days if EF ≤35% (MADIT-II, SCD-HeFT); CRT-D if EF ≤35% + LBBB + QRS ≥150 ms; LVAD (HeartMate 3 [Abbott]) or cardiac transplant evaluation if advanced HF persists at 3 months; cardiac rehab referral; HF clinic 1–2 weeks; early advanced HF team involvement before discharge; advance care planning

⚠ Red Flags

• STEMI + cardiogenic shock: every minute of delayed PCI ↑mortality; SHOCK trial NNT 8 to save one life at 1 year with early revascularization; activate cath lab simultaneous with stabilization — not sequential; CULPRIT-SHOCK: PCI culprit vessel only in STEMI-CS + multivessel CAD (staged non-culprit PCI later)

• Mechanical complications post-STEMI (Days 3–7): new systolic murmur = EMERGENCY ECHO; papillary muscle rupture (acute severe MR — emergent MV surgery + IABP bridge); VSD (holosystolic murmur LLSB + biventricular failure + O2 step-up RA→RV — emergent surgical repair); free wall rupture (PEA + tamponade — OR); all carry 50–90% mortality without surgical intervention

• IABP-SHOCK II (2012, NEJM): IABP does NOT ↓30-day mortality vs optimal medical therapy in STEMI-CS; IABP is not obsolete but is not the primary MCS in STEMI-CS; Impella CP (Abiomed) preferred for hemodynamic support; IABP remains useful as bridge to surgery for mechanical complications

• Inotropes in tamponade: giving dobutamine (Dobutrex) or milrinone (Primacor) to a patient in tamponade → temporary partial improvement → missed diagnosis → continued compression → cardiac arrest; always do echo FIRST in any hypotensive patient; tamponade = pericardiocentesis, not inotropes

• Escalating inotropes without MCS in SCAI Stage D: inotrope escalation beyond dobutamine (Dobutrex) 10–15 mcg/kg/min or milrinone (Primacor) >0.5 mcg/kg/min without MCS = high arrhythmia risk without adequate hemodynamic benefit; Impella CP (Abiomed) provides superior hemodynamic support with less arrhythmia burden; escalate MCS, not inotropes

• BB in active cardiogenic shock (SBP <85 + signs of hypoperfusion) → negative inotropy → ↓CO → worsening shock; hold BB during active CS; taper if possible (abrupt stop = rebound ischemia); restart at low dose during hemodynamic recovery

• Fulminant giant cell myocarditis without biopsy: lethal within days to weeks without MCS + immunosuppression; always perform endomyocardial biopsy in CS of unknown etiology especially in young patients without obvious cause; giant cells on biopsy = immunosuppression (methylprednisolone + cyclosporine [Sandimmune]) + transplant evaluation

Senior IM Resident Pearls

• SCAI Shock Classification — stage the patient immediately on recognition: Stage A = at-risk; B = beginning (biomarkers+, still compensating); C = classic (hypotension + hypoperfusion — START MCS here, not Stage D); D = deteriorating (MCS now, escalate); E = extremis (CPR/ECPR); early MCS at Stage C has dramatically better outcomes than rescue MCS at Stage E; most teams intervene too late

• Bedside echo FIRST — determines the entire management algorithm: LV failure → inotropes + MCS; RV failure → fluids + vasopressin (Pitressin) [not norepinephrine (Levophed) alone — ↑PVR]; tamponade → pericardiocentesis before anything else; mechanical complication → surgery; hyperdynamic LV → reconsider diagnosis (not cardiogenic); this decision takes 2 minutes and changes everything

• SOAP II (2010, NEJM): norepinephrine (Levophed) vs dopamine (Intropin) in shock → equivalent 28-day mortality but norepinephrine ↓atrial arrhythmias (24.1% vs 12.4%); use norepinephrine (Levophed) as first-line vasopressor in all shock types including cardiogenic; dopamine only if bradycardia is a component

• SHOCK trial (1999, NEJM) — most important CS evidence: early revascularization vs aggressive medical stabilization in STEMI + CS → ↓1-year mortality (50.3% vs 63.1%; NNT 8); benefit continues at 6 years; early PCI is the only intervention proven to improve mortality in STEMI-CS; do not let hemodynamic stabilization delay cath lab activation

• CULPRIT-SHOCK (2017, NEJM): culprit-only PCI vs multivessel PCI at time of STEMI + CS → culprit-only ↓30-day death/RRT (45.9% vs 55.4%; NNT 10); do NOT perform complete revascularization in STEMI-CS at index cath; PCI culprit → stabilize → staged non-culprit PCI later when hemodynamically stable; one of the most impactful RCTs in interventional cardiology

• IABP-SHOCK II (2012, NEJM): IABP vs no IABP in STEMI-CS → no ↓30-day or 12-month mortality; IABP is not the first-choice MCS for STEMI-CS; Impella CP (Abiomed) preferred for hemodynamic support; IABP remains useful bridge to surgery in mechanical complications; retiring IABP as "routine" CS intervention is evidence-based

• RV failure in CS — different algorithm: vasopressin (Pitressin) preferred pressor (↑SVR without ↑PVR — ↑PVR worsens RV outflow obstruction); IV fluid loading (RV requires preload); avoid diuretics (↓RV preload → ↓CO); milrinone (Primacor) preferred inotrope (↓PVR); norepinephrine (Levophed) alone ↑PVR → worsen RV failure; Impella RP (Abiomed) or TandemHeart for refractory RV failure

• Common mistake — diuresing a hypotensive patient: "the patient has pulmonary edema AND hypotension" → reflex furosemide (Lasix) → ↓preload → ↓CO → worsening shock; confirm elevated filling pressures (echo: IVC plethora + PCWP >18) before ANY diuresis in CS; if MAP <65 → vasopressors FIRST → stabilize MAP → then cautious diuresis guided by Swan-Ganz or echo; diuresis in hypotension without hemodynamic guidance = dangerous