What are the latest management strategies for hypertrophic cardiomyopathy (HCM)?

Latest Management Strategies for Hypertrophic Cardiomyopathy (HCM)

The management of hypertrophic cardiomyopathy requires a stepwise pharmacological approach starting with beta-blockers, followed by non-dihydropyridine calcium channel blockers, and then adding myosin inhibitors or disopyramide for persistent symptoms, with septal reduction therapy reserved for medication failures. 1

Pharmacological Management

First-Line Therapy

• Beta-blockers:
  • Should be titrated to maximally tolerated doses
  • Target heart rate: 50-60 beats per minute
  • Mechanism: Reduce early LV ejection acceleration and systolic force on mitral leaflet 1
  • Goal: Improve symptoms by reducing LVOT gradient during exercise

Second-Line Therapy

• Non-dihydropyridine calcium channel blockers (verapamil, diltiazem):
  • Particularly effective for chest pain and improving exercise capacity 1
  • Should be used cautiously in patients with high resting gradients due to potential vasodilatory effects 2
  • Contraindicated if pre-excitation is present 3

Third-Line Therapy

• Disopyramide:

  • Can be added in combination with beta-blockers or calcium channel blockers
  • Requires QTc interval monitoring during dose titration 1
  • Most effective agent for lowering gradient in head-to-head comparisons 2
  • Consider adding pyridostigmine to mitigate vagolytic side effects 2

• Myosin inhibitors:

  • Newer agents for adult patients with persistent symptoms despite standard therapy 1

Contraindicated Medications

• Nitrates: Contraindicated due to potential worsening of LVOTO 1
• Vasodilators (ACE inhibitors, ARBs): Should be avoided in obstructive HCM 1
• Digoxin: Should be avoided in patients with LVOTO and normal EF 3
• Class IC antiarrhythmics (flecainide, propafenone): Should be avoided as they may worsen conduction and increase ventricular rate 3

Management of Atrial Fibrillation

AF is common in HCM patients and associated with unfavorable prognosis, including increased risk of heart failure, death, and stroke 3.

Anticoagulation

• All HCM patients with AF (paroxysmal, persistent, or permanent) should receive oral anticoagulation with vitamin K antagonists (target INR 2.0-3.0) 3
  • CHA₂DS₂-VASc score is not recommended for risk stratification in HCM patients 3
  • Lifelong therapy is recommended, even when sinus rhythm is restored 3
  • Even patients with short episodes of AF should be strongly considered for anticoagulation 3

Rate Control

• Beta-blockers and non-dihydropyridine calcium channel blockers (alone or in combination)
  • Target resting heart rate < 100 BPM 3
  • Assess adequacy of rate control during exercise
  • If rate control cannot be achieved, consider AV node ablation and permanent pacing 3

Rhythm Control

• Amiodarone: Safe and effective for HCM patients 3
• Disopyramide: Safety and efficacy for AF in HCM not well established 3
• Radiofrequency ablation: Consider for symptomatic AF refractory to medical therapy
  • Early success and complication rates similar to patients without HCM 3

Septal Reduction Therapy

Indicated when medical therapy fails to control symptoms:

• Surgical myectomy
• Alcohol septal ablation
• Should be performed only at experienced centers 1

Lifestyle Modifications

• Physical activity:

  • Participation in moderate recreational activities is reasonable after comprehensive evaluation
  • Universal restriction from physical activity not indicated for most HCM patients 1
  • Avoid dehydration and excess alcohol consumption, particularly with LVOTO 1

• Weight management:

  • Comprehensive lifestyle interventions for weight loss recommended
  • May lower risk of LVOTO, heart failure, and atrial fibrillation in patients with obesity 1

Monitoring and Follow-up

• Regular assessment of symptom status
• Periodic echocardiography every 1-2 years to evaluate:
  • LVOT gradient
  • Myocardial hypertrophy
  • Mitral regurgitation
  • Myocardial function 1
• Extended ambulatory monitoring for high-risk patients with AF 1

Clinical Pitfalls to Avoid

1. Inappropriate use of vasodilators: Can worsen LVOT obstruction and cause clinical deterioration
2. Underutilization of anticoagulation: All HCM patients with AF should receive anticoagulation regardless of CHA₂DS₂-VASc score
3. Inadequate beta-blocker dosing: Should be titrated to target heart rate of 50-60 BPM
4. Overreliance on verapamil in patients with high resting gradients: May worsen obstruction due to vasodilatory effects
5. Failure to refer to specialized centers for septal reduction therapy when medical therapy fails

By following these evidence-based strategies, clinicians can optimize management of HCM patients to reduce symptoms, prevent complications, and improve quality of life.