Treatment of hypertrophic cardiomyopathy

(Circ 2020;142:e558; Lancet 2021;398:2102; JACC 2022;79:390)

Heart failure

• ⊖ inotropes/chronotropes:

  • β-blockers (JACC 2021;78:2505),
  • CCB (verapamil),
  • disopyramide

• Careful use of diuretics, because may further ↓ preload. If LVOTO, avoid vasodilators. Avoid digoxin b/c ↑ contractility and ∴ outflow obstruction.

• If sx refractory to drug Rx + obstructive physio. (∇ ≥30 mmHg at rest or w/ provocation):

  • (a) Surgical myectomy: long-term ↓ symptoms in 90% (Circ 2014;130:1617)
  • (b) Alcohol septal ablation (JACC 2018;72:3095): ∇ ↓ by ~80%, only 5–20% remain w/ NYHA III–IV sx; 14% require repeat ablation or myectomy. Good alternative for older Pts, multiple comorbidities. Complic: transient (& occ. delayed) 3° AVB w/ 10–20% req. PPM; VT due to scar formation.
  • Mavacamten (cardiac myosin inhibitor) ↓ HF sxs & LVOT ∇ (Lancet 2020;396,750)
    • If refractory to drug therapy and there is nonobstructive pathophysiology: transplant

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• Acute HF: can be precip. by dehydration or tachycardia; Rx w/ fluids, βB, phenylephrine
• AF: rate control w/ βB, maintain SR w/ disopyramide or amio; low threshold to anticoag
• ICD if VT/VF. Reasonable for 1° prevention if ≥1 risk factor:
• ⊕ FHx SCD, unexplained syncope, LV wall ≥30 mm, LV aneurysm or EF <50%; consider if NSVT, failure of SBP to ↑ or fall from peak ≥20 mmHg w/ exercise, ? extensive MRI delayed enhancement. EPS not useful. HCM Risk-SCD Score (https://doc2do.com/hcm/webHCM.html).
• Counsel to avoid dehydration, extreme exertion
• 1st-degree relatives: screen w/ TTE q12–18m as teen or athlete then q5y as adult, ECG (because timing of HCMP onset variable). Genetic testing if known mutation.