This handout is for nstemi in hypertrophic cardiomyopathy — microvascular ischemia + supply-demand mismatch. Your care team identified this based on: patient with known hypertrophic cardiomyopathy (resting or provocable lvot gradient ≥30 mmhg, septal thickness ≥15 mm) presenting with ischemic chest pain + hstn rise/fall + non-st-elevation ecg — microvascular ischemia / supply-demand crisis on differential.
Other reasons your team may use this plan: nste-acs workup angiogram shows unobstructed epicardial coronaries + bedside echo reveals asymmetric septal hypertrophy (≥15 mm) with sam and dynamic lvot gradient → hcm-microvascular nstemi substrate; stress cmr shows first-pass perfusion defect + mid-wall lge in hypertrophied septum + unobstructed epicardial coronaries — confirms hcm-microvascular mi substrate per petersen 2007 pmid 17502574; new-onset afib with rapid ventricular response in hcm patient + hstn rise/fall + non-st-elevation ecg — loss of atrial kick destabilizes lv filling → subendocardial ischemia / supply-demand mismatch in stiff hypertrophied lv.
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 → relieves microvascular ischemia by improving subendocardial perfusion gradient; 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 → improves subendocardial perfusion → relieves microvascular ischemia; titratable, off rapidly if hemodynamic compromise |
| aspirin | 81 mg daily (no high-dose load if no atherosclerotic substrate identified) OR 162-325 mg load if concurrent atherosclerotic NSTEMI on imaging | PO | daily indefinitely | ASA monotherapy reasonable in HCM-microvascular NSTEMI (no plaque rupture substrate); some authors continue indefinitely for general cardiovascular risk reduction; DAPT NOT routine (reserve P2Y12 only if concurrent atherosclerotic CAD on imaging) — different from atherosclerotic NSTEMI default |
| metoprolol_succinate | 25-50 mg PO daily titrate to maximally tolerated (target HR 60-80) | PO | daily | ACC/AHA 2024 HCM Class I — first-line chronic β-blockade for symptomatic HCM; reduces inotropy + lengthens diastole → reduces LVOT gradient → improves microvascular perfusion |
| carvedilol | 3.125 mg BID titrate to max tolerated (target HR 60-80) | PO | BID indefinitely | ACC/AHA 2024 HCM Class I alternative; α1-blockade caution in obstructive HCM with very high gradient (vasodilator effect may worsen gradient — start low) — prefer metoprolol succinate as first choice in pure HOCM |
| 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); improves diastolic relaxation and microvascular perfusion |
| 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 → improves microvascular perfusion; 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; ARISTOTLE 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 |
Plan: HCM-microvascular NSTEMI regimen — overrides parent cardio.nstemi.core.v1 vasodilator + DAPT + statin defaults; uses BB or non-DHP CCB + ASA monotherapy + AC for AF (Class I regardless of CHA2DS2-VASc); chronic ladder: BB/CCB → disopyramide → mavacamten → septal reduction therapy — ACC/AHA 2024 HCM Guideline (Ommen) + ESC 2023 cardiomyopathies (Arbelo PMID 37622666) + EXPLORER-HCM (Olivotto PMID 32861276)
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 genetic counseling + screening (50% autosomal dominant inheritance per ACC/AHA 2024); mavacamten REMS echo q4w during titration then q12w maintenance; ICD/septal reduction decision finalized per SCD criteria; AC continuation indefinite if AF; sports clearance shared decision; cardiac rehab if NYHA II-III (modified intensity — avoid heavy isometric exercise); long-term cardiology surveillance
Guideline: ACC/AHA 2024 HCM Guideline (Ommen) + ESC 2023 cardiomyopathies (Arbelo PMID 37622666) + ESC 2014 HCM (Elliott PMID 25173338) for SCD risk + 2025 ACC/AHA ACS Guideline (Rao) for parent ACS arc