This handout is for hypertrophic cardiomyopathy with acute decompensation. Your care team identified this based on: acute dyspnea / orthopnea / pre-syncope in patient with known hcm (resting or provocable lvot gradient ≥30 mmhg) — sudden hemodynamic deterioration.
Other reasons your team may use this plan: bedside echo: new or worsened sam-mediated lvot obstruction with dynamic gradient (rest ≥50 mmhg or with valsalva/exercise provocation) in hcm patient; 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; hcm patient with precipitant: gi losses, sepsis, fever, postoperative volume shifts, or inadvertent diuretic over-shoot → acute lvot obstruction crisis.
Take these medications exactly as prescribed. Do not stop or change a dose without talking to your provider.
| Medication | Starting dose | How | When | What it does |
|---|---|---|---|---|
| phenylephrine | 50-200 mcg IV bolus or 0.5-3 mcg/kg/min infusion titrate to MAP ≥65 | IV | bolus or continuous infusion | Pure α-agonist increases afterload → reduces LVOT gradient by improving aortic ejection and abolishing SAM; preferred over norepinephrine (β-component worsens obstruction) and ABSOLUTELY preferred over inotropes |
| esmolol | 500 mcg/kg IV bolus then 50-300 mcg/kg/min infusion titrate to HR <80 | IV | continuous infusion | Short-acting cardioselective β-blocker lengthens diastolic filling time, reduces inotropy → reduces LVOT gradient; titratable, off rapidly if hemodynamic compromise |
| metoprolol_tartrate | 25 mg PO BID titrate to maximally tolerated | PO | BID | ACC/AHA 2024 HCM Class I — first-line chronic β-blockade for symptomatic HCM; reduces inotropy + lengthens diastole |
| verapamil | 120 mg PO daily extended-release titrate to 480 mg/d max | PO | daily ER | ACC/AHA 2024 HCM Class I alternative — non-DHP CCB; CAUTION in obstructive HCM with very high gradient or heart failure (vasodilator effect can worsen gradient — start low) |
| disopyramide | 40-50 mg PO TID-QID extended-release titrate to 600-800 mg/d max; renal-adjusted | PO | TID-QID | ACC/AHA 2024 HCM Class IIa — negative inotrope reduces SAM and LVOT gradient; QT prolongation + anticholinergic effects + proarrhythmic — monitor QT, K, Mg |
| mavacamten | 5 mg PO daily start; titrate q4w per echo per REMS (max 15 mg/d) | PO | daily | ACC/AHA 2024 HCM Class IIa — first-in-class cardiac myosin inhibitor; EXPLORER-HCM PMID 32861276 (Olivotto Lancet 2020): 30% relative improvement in pVO2 + ~47% reduction in resting LVOT gradient; VALOR-HCM 2023: reduces septal reduction therapy referrals; REMS program — echo q4w during titration to detect LVEF drop <50% |
| apixaban | 5 mg PO BID (2.5 mg BID per FDA dose-reduction criteria) | PO | BID indefinite | ACC/AHA 2024 HCM Class I — ANY AF in HCM = anticoagulate regardless of CHA2DS2-VASc score; DOAC preferred over warfarin; RE-LY/ARISTOTLE/ROCKET-AF/ENGAGE class evidence applies |
| rivaroxaban | 20 mg PO daily with food (15 mg if CrCl 15-50) | PO | daily indefinite | ACC/AHA 2024 HCM Class I — DOAC alternative for AF in HCM |
| warfarin | 5 mg PO daily; INR target 2-3 | PO | daily indefinite | ACC/AHA 2024 HCM Class I if DOAC contraindicated; INR 2-3 |
Plan: HCM acute decompensation — preload/afterload-dependent: fluids + phenylephrine + esmolol + AVOID inotropes/vasodilators; chronic: BB/CCB/disopyramide → mavacamten → septal reduction therapy (ACC/AHA 2024 HCM)
Contact your care team if any of the following happen:
Call 911 or go to the nearest emergency room right away if you have:
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
Guideline: ACC/AHA 2024 HCM Guideline + ESC 2023 cardiomyopathies (Arbelo) + ESC 2014 HCM (Elliott) for SCD risk