What is the initial management approach for patients with hypertrophic cardiomyopathy?

Initial Management Approach for Hypertrophic Cardiomyopathy

The initial management of hypertrophic cardiomyopathy (HCM) should focus on symptom alleviation, lifestyle modifications, and pharmacological therapy tailored to the presence or absence of left ventricular outflow tract obstruction (LVOTO). 1

Diagnostic Evaluation

• Initial evaluation should include transthoracic 2D and Doppler echocardiography at rest and during Valsalva maneuver in sitting, semi-supine, and standing positions to assess for LVOTO 1
• Comprehensive evaluation of LV diastolic function is recommended, including pulsed Doppler of mitral valve inflow, tissue Doppler velocities, pulmonary vein flow velocities, and left atrial size measurement 1
• In symptomatic patients with resting or provoked LVOT gradient <50 mmHg, exercise echocardiography is recommended to detect provocable obstruction 1
• Cardiovascular magnetic resonance imaging (CMR) should be considered at baseline assessment if resources permit, especially for patients with poor acoustic windows or when certain LV regions are poorly visualized 1

Pharmacological Management

For Obstructive HCM:

• First-line therapy: Non-vasodilating beta-blockers are recommended as initial treatment for symptomatic patients with LVOTO 1
• Alternative first-line: Calcium channel blockers (verapamil or diltiazem) are reasonable alternatives when beta-blockers are not tolerated or ineffective 1
• Advanced therapy: For patients with persistent symptoms despite beta-blockers or calcium channel blockers, options include:
  • Adding disopyramide (in combination with AV nodal blocking agent) 1
  • Cardiac myosin inhibitors (mavacamten) in adult patients 1
  • Septal reduction therapy when performed at experienced centers 1

For Non-obstructive HCM:

• Beta-blockers or calcium channel blockers may help improve diastolic filling and relieve symptoms 1
• For younger patients (≤45 years) with non-obstructive HCM due to pathogenic cardiac sarcomere variants and mild phenotype, valsartan may be beneficial to slow adverse cardiac remodeling 1

Important Medication Considerations:

• Avoid peripheral vasodilators (dihydropyridine calcium channel blockers, ACE inhibitors, ARBs) in patients with LVOTO as they can worsen obstruction 1
• Use diuretics cautiously as they can exacerbate LVOTO by decreasing preload 1
• Verapamil carries specific warnings for HCM patients - pulmonary edema and severe hypotension have been reported in patients with severe LVOTO 2
• Avoid PDE5 inhibitors, particularly in patients with LVOTO 1

Lifestyle Modifications

• Exercise recommendations:

  • Avoid competitive sports activities 1
  • Participation in vigorous recreational activities is reasonable after comprehensive evaluation and shared decision-making 1
  • Universal restriction from vigorous physical activity is not indicated for most patients 1

• Diet and alcohol:

  • Maintain healthy body mass index 1
  • Consider smaller, more frequent meals to avoid chest pain, particularly with LVOTO 1
  • Avoid dehydration and excess alcohol, especially with LVOTO 1

• Other lifestyle considerations:

  • Smoking cessation should be encouraged 1
  • Provide counseling regarding sexual activity and potential medication effects on sexual performance 1
  • Most patients can continue normal job activities, but heavy manual jobs involving strenuous activity should be discussed with specialists 1

Risk Stratification for Sudden Cardiac Death

• For patients with ≥1 major SCD risk factor, discussion of estimated 5-year sudden death risk is useful during shared decision-making for ICD placement 1
• Extended ambulatory monitoring is recommended to screen for atrial fibrillation in high-risk patients 1

Special Considerations

• Endocarditis prophylaxis: Infective endocarditis in HCM is virtually confined to patients with LVOTO. The incidence is 3.8 per 1000 person-years with a 4.3% probability at 10 years in patients with LVOTO 1

• Pregnancy: Mavacamten is contraindicated during pregnancy due to potential teratogenic effects 1

• Advanced HF: In patients who develop persistent systolic dysfunction (LVEF <50%), cardiac myosin inhibitors should be discontinued 1

Common Pitfalls to Avoid

• Failure to identify LVOTO during initial evaluation, which can be provoked with exercise or Valsalva maneuver 1
• Using vasodilators in patients with LVOTO, which can worsen obstruction 1
• Aggressive diuresis, which can decrease preload and augment LVOTO 1
• Overlooking atrial fibrillation, which requires appropriate anticoagulation 1
• Combining verapamil with quinidine in HCM patients, which has resulted in significant hypotension 2