What is the treatment for Hypertrophic Cardiomyopathy (HCM)?

Treatment for Hypertrophic Cardiomyopathy (HCM)

Beta-blocking drugs are the first-line treatment for symptoms (angina or dyspnea) in adult patients with obstructive or nonobstructive HCM, with verapamil recommended as second-line therapy for those who don't respond to beta-blockers or have contraindications to them. 1

Pharmacological Management

First-Line Therapy

• Beta-blockers:
  • Recommended for symptomatic patients with either obstructive or nonobstructive HCM 1
  • Should be titrated to a resting heart rate of <60-65 bpm for optimal symptom control 1
  • Use with caution in patients with sinus bradycardia or severe conduction disease 1
  • Dosing: Titrate up to maximum tolerated doses as needed for symptom control 1

Second-Line Therapy

• Verapamil:
  • Recommended when beta-blockers are ineffective, not tolerated, or contraindicated 1
  • Start at low doses and titrate up to 480 mg/day as needed 1
  • Caution: Use carefully in patients with high gradients, advanced heart failure, or sinus bradycardia 1, 2
  • Avoid in patients with obstructive HCM who have systemic hypotension or severe dyspnea at rest 1

Additional Pharmacological Options

• Disopyramide:

  • Can be combined with beta-blockers or verapamil for persistent symptoms in obstructive HCM 1
  • Never use disopyramide alone in patients with atrial fibrillation 1

• Diuretics:

  • Reasonable to add in nonobstructive HCM when dyspnea persists despite beta-blockers or verapamil 1
  • May be used cautiously in obstructive HCM when congestive symptoms persist 1

Medications to Avoid

• Dihydropyridine calcium channel blockers (e.g., nifedipine): Potentially harmful in patients with resting or provocable LVOT obstruction 1
• Digitalis: Potentially harmful for treating dyspnea in HCM without atrial fibrillation 1
• Positive inotropic drugs (dopamine, dobutamine, norepinephrine): Potentially harmful for acute hypotension in obstructive HCM 1
• ACE inhibitors/ARBs: Use with caution; potentially harmful in patients with resting or provocable LVOT obstruction 1

Non-Pharmacological Management

Septal Reduction Therapy

• Reserved for patients with severe drug-refractory symptoms and LVOT obstruction 1
• Should be performed only by experienced operators in comprehensive HCM clinical programs 1
• Should NOT be performed in asymptomatic patients regardless of obstruction severity 1

Acute Hypotension Management

• Intravenous phenylephrine (or another pure vasoconstrictor) is recommended for acute hypotension in obstructive HCM not responding to fluid administration 1

Lifestyle Modifications

• Low-intensity aerobic exercise is reasonable as part of a healthy lifestyle 1
• Treat comorbidities (hypertension, diabetes, hyperlipidemia, obesity) according to existing guidelines 1

Special Populations

Children and Adolescents

• Beta-blockers may be useful for symptom control 1
• Monitor for side effects including depression, fatigue, or impaired scholastic performance 1

Comparative Effectiveness

Recent data suggests that in low-risk HCM patients, verapamil therapy was not associated with a higher incidence of adverse events compared to beta-blocker therapy 3, though beta-blockers remain the first-line treatment according to guidelines.

Treatment Algorithm

1. Asymptomatic patients:

   • No specific drug therapy required
   • Manage comorbidities and allow low-intensity exercise

2. Symptomatic patients:

   • Start with beta-blockers, titrate to heart rate <60-65 bpm
   • If symptoms persist or beta-blockers not tolerated → Add or switch to verapamil
   • If still symptomatic with obstructive HCM → Add disopyramide
   • If still symptomatic with nonobstructive HCM → Add diuretics
   • For refractory symptoms with obstruction → Consider septal reduction therapy

This approach has contributed to reducing HCM-related mortality to <1% per year in contemporary practice 4.