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cardio.acute-hf.hcm-decompensation.v1

Hypertrophic cardiomyopathy with acute decompensation

cardiologyacuteadultacuteinpatienttransitionoutpatient
Start encounter →Print handoutPRODUCTION

Phase E variant of cardio.acute-hf.core.v1 — narrowed to HCM acute decompensation. Inherits the parent ADHF decompensation arc via routing; specializes for the HCM-specific OBSTRUCTION CRISIS physiology (SAM-driven dynamic LVOT obstruction + diastolic dysfunction + AFib intolerance) which inverts standard ADHF management. Manifest pointer reuses cardio.acute-hf.core.v1 manifest. Design-brief pointer reuses parent (HCM-specific differences documented inline). Phenotypes covered: (1) obstructive HCM (HOCM) with SAM-mediated LVOT obstruction crisis (SBP <90 → fluids + phenylephrine + esmolol; never inotropes); (2) HCM with new-onset AFib RVR (loss of atrial kick destabilizes diastolic filling — emergent rate control or cardioversion + Class I AC regardless of CHA2DS2-VASc); (3) end-stage dilated HCM phenotype (~5% of HCM with LVEF <50% — switch to cardio.hfref.core.v1 for standard HFrEF GDMT 4-pillar). Treatment paradox vs standard ADHF: give FLUIDS (not diurese aggressively), give pure α-agonist phenylephrine (not norepinephrine), give esmolol IV (lengthen diastole, reduce inotropy), AVOID dobutamine/milrinone/epinephrine (worsen SAM and LVOT gradient), AVOID NTG/ACEi/ARB/ARNI (vasodilator drops afterload → worsens gradient), AVOID DHP CCB (amlodipine vasodilator effect). Chronic disease-modifying therapy ladder: BB or non-DHP CCB → disopyramide (negative inotrope) → mavacamten (cardiac myosin inhibitor — first FDA-approved disease-modifying therapy per EXPLORER-HCM Class IIa) → septal reduction therapy (surgical myectomy gold standard or alcohol septal ablation) for refractory obstruction with LVOT gradient ≥50 mmHg + NYHA III-IV. SCD risk stratification: ESC 2014 HCM-RISK-SCD 5-year score + ACC/AHA 2024 modifiers (LGE >15% on CMR, family history of SCD, unexplained syncope, NSVT on Holter, apical aneurysm, LV wall thickness ≥30 mm) → primary-prevention ICD per individualized risk-benefit. Status INTEGRATED. Authored 2026-05-15 by shard-06-cardio-acute as HCM acute decompensation variant.

Entry points (4)

  • symptom
    Acute dyspnea / orthopnea / pre-syncope in patient with known HCM (resting or provocable LVOT gradient ≥30 mmHg) — sudden hemodynamic deterioration
    acute_dyspnea_in_known_hcm_patient
  • imaging
    Bedside echo: new or worsened SAM-mediated LVOT obstruction with dynamic gradient (rest ≥50 mmHg or with Valsalva/exercise provocation) in HCM patient
    new_lvot_obstruction_with_sam_on_bedside_echo
  • symptom
    New-onset AFib with rapid ventricular response in HCM — loss of atrial kick → catastrophic LV filling drop because stiff hypertrophied LV depends on atrial systole
    new_atrial_fibrillation_with_acute_decompensation_in_hcm
  • history
    HCM patient with precipitant: GI losses, sepsis, fever, postoperative volume shifts, or inadvertent diuretic over-shoot → acute LVOT obstruction crisis
    precipitant_dehydration_or_fever_or_postop_in_hcm

Required inputs (15)

  • agerequired
    demographic • used at CONTEXT
    Age input for ESC HCM-RISK-SCD; older patients more likely to have AF and require AC; mavacamten and disopyramide tolerability depends on age and frailty
  • sbprequired
    vital • used at RED_FLAGS
    Hypotension in HCM = SAM-mediated LVOT obstruction collapse — treat with FLUIDS + phenylephrine, NOT inotropes; SBP <90 with HCM precipitant triggers obstruction-crisis pathway
  • hrrequired
    vital • used at RED_FLAGS
    Tachycardia worsens LVOT gradient by shortening diastolic filling; HR target <80 bpm with esmolol IV; new AFib RVR requires emergent rate control or cardioversion
  • spo2required
    vital • used at RED_FLAGS
    Pulmonary edema secondary to acute diastolic dysfunction + SAM-driven mitral regurgitation — SpO2 < 92% triggers NIPPV (use carefully — avoid pre-load drop)
  • echo_lvot_gradientrequired
    imaging • used at INITIAL_WORKUP
    Bedside or formal TTE — resting + provocable LVOT gradient, SAM, septal thickness, LVEF, mitral regurgitation severity — drives ALL drug decisions
  • lv_wall_thicknessrequired
    imaging • used at INITIAL_WORKUP
    Asymmetric septal hypertrophy ≥15 mm (≥13 mm with FH or genetic confirmation) — diagnostic anchor; ≥30 mm = high-SCD-risk band per ACC/AHA 2024 HCM
  • cmr_lge
    imaging • used at RISK_STRATIFICATION
    CMR LGE quantifies fibrosis burden — high LGE (>15% LV mass) refines SCD risk upward beyond HCM-RISK-SCD score; identifies apical aneurysm
  • ecgrequired
    imaging • used at INITIAL_WORKUP
    LVH voltage criteria, lateral T-wave inversion, abnormal Q-waves; new AFib detection drives immediate AC + rate/rhythm strategy
  • creatininerequired
    lab • used at TREATMENT
    eGFR for disopyramide (renal-adjusted), mavacamten (CYP-mediated metabolism — not strict renal cutoff but used in monitoring), AC dosing if AF
  • nt_probnprequired
    lab • used at INITIAL_WORKUP
    Elevated in HCM acute decompensation; useful for trending decongestion but interpret cautiously (chronic elevation in HCM regardless of acute state)
  • potassiumrequired
    lab • used at CONTEXT
    HypoK in hypertrophied stiff LV worsens VT/VF risk; also affects disopyramide proarrhythmia; replete K to ≥4.0
  • magnesium
    lab • used at CONTEXT
    HypoMg ↑ TdP risk on disopyramide (QT prolongation); maintain Mg ≥2.0
  • family_history_scdrequired
    history • used at CONTEXT
    ESC HCM-RISK-SCD component + ACC/AHA 2024 SCD risk stratification; cascade screening referral
  • unexplained_syncope
    history • used at RISK_STRATIFICATION
    Major SCD risk modifier in HCM (ESC 2014; ACC/AHA 2024)
  • current_medsrequired
    history • used at CONTEXT
    Detect inadvertent vasodilators (ACEi, ARB, nitrates), inotropes, or aggressive diuretics that may have precipitated obstruction crisis; need to stop or switch

12-phase flow (12)

  1. 1FRAME
    Acute decompensation in HCM = dynamic LVOT obstruction (SAM-driven) + diastolic dysfunction + often AFib — preload/afterload-dependent. Treatment paradox vs ADHF: give fluids, give phenylephrine, slow HR with esmolol, AVOID inotropes / vasodilators / aggressive diuresis
    inputs: sbp, hr, echo_lvot_gradient
    advance: HCM-specific physiology framed before any drug ordered
  2. 2ENTRY
    Recognize HCM patient in acute deterioration; bedside echo for LVOT gradient + SAM + LVEF; ECG for AFib; identify precipitant (dehydration, fever, AFib, postop)
    inputs: age
    advance: phenotype + precipitant documented
  3. 3CONTEXT
    Family history SCD, prior HCM workup (CMR, Holter, genetic testing), current chronic regimen (BB, CCB, disopyramide, mavacamten), home meds review for inadvertent vasodilators / inotropes
    inputs: sbp, hr, creatinine, potassium, family_history_scd, current_meds
    advance: context complete
  4. 4RED_FLAGS
    SAM-mediated LVOT obstruction crisis (SBP <90 + worsening gradient — give fluids + phenylephrine, NOT inotropes); new AFib with RVR (loss of atrial kick → emergent rate control / cardioversion); ventricular arrhythmia / SCD risk; septal reduction therapy decision; mavacamten-related LVEF drop <50%
    inputs: sbp, hr, spo2
    actions: acute_pulm_edema, cardiogenic_shock
    advance: red flags screened and obstruction crisis resolved
  5. 5INITIAL_WORKUP
    TTE (resting + provocative LVOT gradient, SAM, septal thickness, LVEF, MR), ECG, NT-proBNP, BMP, CBC, troponin (rule out concurrent ACS), CXR; consider cardiac MRI if not recent (LGE for SCD refinement)
    inputs: echo_lvot_gradient, lv_wall_thickness, ecg, nt_probnp, creatinine
    actions: panel.cardiac, panel.renal
    advance: phenotype + LVOT gradient + LVEF documented
  6. 6BRANCHING_WORKUP
    Identify precipitant — sepsis (sepsis bundle), AFib (AC + rate/rhythm), ACS (troponin trend, cath if elevated and hemodynamically compatible), inadvertent vasodilator (stop), pregnancy (specialist co-management), HOCM provocative testing (Valsalva at bedside)
    inputs: current_meds
    advance: precipitant identified or empirical management initiated
  7. 7DIFFERENTIAL
    Obstructive (HOCM, resting or provocable gradient ≥30 mmHg) vs non-obstructive vs apical HCM vs end-stage dilated phenotype (rare 5% with LVEF <50% — classic ADHF GDMT applies); exclude phenocopies (TTR amyloid, Fabry, Danon, athlete heart, hypertensive HD)
    inputs: echo_lvot_gradient, lv_wall_thickness
    advance: phenotype assigned (obstructive vs non-obstructive vs end-stage dilated)
  8. 8RISK_STRATIFICATION
    ESC 2014 HCM-RISK-SCD 5-year score (driver for primary-prevention ICD); ACC/AHA 2024 multi-modality refinement (LGE, family history, syncope, NSVT, apical aneurysm, LV thickness ≥30 mm); CHA2DS2-VASc inapplicable for stroke (ANY AF in HCM = Class I AC); MAGGIC if end-stage dilated phenotype; HAS-BLED for AC bleed risk
    inputs: family_history_scd, cmr_lge, unexplained_syncope
    actions: calc.cha2ds2vasc, calc.maggic
    advance: SCD risk + AC decision + ICD decision documented
  9. 9TREATMENT
    ACUTE: fluids 250-500 mL crystalloid bolus, phenylephrine 50-200 mcg IV bolus or 0.5-3 mcg/kg/min infusion for hypotension, esmolol 50-300 mcg/kg/min IV titrate to HR <80, AC if AFib, electrical cardioversion if hemodynamically unstable AFib, AVOID dobutamine/milrinone/epinephrine, AVOID NTG/ACEi/ARB, AVOID aggressive diuresis (use cautiously if frank pulmonary edema). CHRONIC: BB or non-DHP CCB (verapamil/diltiazem) at maximally tolerated dose; disopyramide ≥40-50 mg/d titrate (negative inotrope, lengthens QT — monitor); mavacamten 5 mg PO daily start, titrate q4w with echo per REMS (Class IIa per ACC/AHA 2024 for persistent symptomatic obstruction); septal reduction therapy (surgical myectomy gold standard, alcohol septal ablation alternative) for refractory obstruction with LVOT gradient ≥50 mmHg + NYHA III-IV; ICD per ESC 2014 + ACC/AHA 2024 SCD criteria; AC for AF (DOAC preferred — apixaban / rivaroxaban — Class I regardless of CHA2DS2-VASc per ACC/AHA 2024 HCM)
    inputs: sbp, hr, creatinine
    advance: acute hemodynamic crisis resolved + chronic disease-modifying plan documented
  10. 10DISPOSITION
    ICU/CICU if hypotensive or arrhythmic; cardiology + electrophysiology consult; HCM specialist referral for mavacamten initiation and septal reduction therapy decision
    advance: unit + specialist referral assigned
  11. 11MONITORING
    Telemetry continuous (VT/VF surveillance + AFib detection); daily echo if mavacamten initiation (REMS — LVEF q4w during titration to detect drop <50%); BMP daily; QT on disopyramide; if AFib AC therapeutic; serial Holter for NSVT (SCD modifier)
    inputs: creatinine, potassium
    actions: panel.cardiac
    advance: monitoring schedule documented
  12. 12FOLLOWUP
    HCM specialist clinic within 1-2 weeks; cascade family screening (genetic counseling); mavacamten REMS echo q4w during titration then q12w maintenance; ICD/septal reduction decision finalised; sports clearance shared decision; cardiac rehab if NYHA II-III
    advance: long-term plan + family screening + follow-up cadence finalised