IDM HCM Treatment Cheatsheet
Key Concept: IDM HCM = dynamic LVOT obstruction from septal thickening. Treat with β-blockers (↑ diastolic filling, ↓ LVOT gradient). Avoid inotropes (dobutamine) and diuretics (furosemide) — both worsen obstruction by reducing LV volume.
| Treatment | Key Features |
|---|
| Propranolol |
- Dynamic LVOT obstruction (hypertrophic septal thickening) → reduce outflow tract gradient
- β-blocker: ↓ heart rate, ↑ filling time, ↑ LV volume → reduces dynamic obstruction
- IDM: maternal hyperglycemia → fetal hyperinsulinemia → glycogen deposition in septum
- Echo shows: ↑ interventricular septal thickness, ↓ LV chamber size
- Do NOT give inotropes (worsen LVOT obstruction); do NOT give diuretics (↓ preload worsens obstruction)
|
| Indomethacin |
- Pharmacologic PDA closure in premature neonates (inhibits prostaglandin synthesis)
- WRONG for HCM: indomethacin does not treat hypertrophic cardiomyopathy
- Preterm <34 weeks: first-line for hemodynamically significant PDA
|
| Dobutamine |
- Inotrope for dilated cardiomyopathy / cardiogenic shock (↓ contractility)
- WRONG for HCM: inotropes increase LVOT obstruction (contraindicated in dynamic obstruction)
|
| Furosemide |
- Loop diuretic for volume overload / CHF with ↑ preload
- WRONG for HCM: reducing preload (LV filling volume) worsens dynamic obstruction
|