What is the initial treatment for hypertrophic cardiomyopathy?

Initial Treatment for Hypertrophic Cardiomyopathy

Beta-blockers are the first-line treatment for symptomatic patients with both obstructive and non-obstructive hypertrophic cardiomyopathy (HCM). 1, 2

First-Line Medical Management

• Beta-blockers should be titrated to maximum tolerated doses with a goal of achieving a resting heart rate of less than 60-65 bpm 1, 2
• Beta-blockers improve symptoms by:
  • Slowing heart rate
  • Improving diastolic function
  • Reducing left ventricular filling pressures
  • Reducing myocardial oxygen demand 3
• Beta-blockers should be used with caution in patients with sinus bradycardia or severe conduction disease 1
• Beta-blockers are particularly important as primary medical therapy in neonates and children with HCM 3

Second-Line Therapy

• For patients who do not respond to beta-blockers, have side effects, or contraindications, non-dihydropyridine calcium channel blockers (verapamil or diltiazem) are recommended 3, 1, 2
• Verapamil can be effective at:
  • Reducing chest pain
  • Improving exercise capacity
  • Improving stress myocardial perfusion defects 3
• Verapamil should be started at low doses and titrated up as needed, with caution in patients with:
  • High outflow gradients
  • Advanced heart failure
  • Sinus bradycardia 1, 2
• Verapamil should be used with extreme caution in patients with obstructive HCM who have systemic hypotension or severe dyspnea at rest 4

Management of Refractory Symptoms

• For patients with obstructive HCM who remain symptomatic despite beta-blockers or calcium channel blockers, disopyramide combined with a beta-blocker or verapamil may be beneficial 1, 2
• Loop or thiazide diuretics may be used cautiously to improve dyspnea and volume overload when present 3
• Aldosterone antagonists may also be considered in some patients 3
• Diuretics should be used intermittently or at chronic low doses to prevent symptomatic hypotension and hypovolemia 3

Special Considerations

• In patients with HCM who develop systolic dysfunction with LVEF <50%, guideline-directed therapy for heart failure with reduced ejection fraction is recommended 3
• In patients with nonobstructive HCM who have a pathogenic cardiac sarcomere genetic variant and mild phenotype, valsartan may be beneficial to slow adverse cardiac remodeling 3
• Avoid using beta-blockers with either verapamil or diltiazem due to potential for high-grade atrioventricular block 1

Medications to Avoid

• Dihydropyridine calcium channel blockers (e.g., nifedipine) are potentially harmful in patients with resting or provocable LVOT obstruction 1, 2
• Vasodilators (ACE inhibitors, ARBs) should be used cautiously or avoided in obstructive HCM, as they may worsen symptoms 2
• Digitalis is potentially harmful in treating dyspnea in HCM patients without atrial fibrillation 1

Advanced Treatment Options

• For severely symptomatic patients with obstructive HCM despite optimal medical therapy, septal reduction therapy should be considered, including:
  • Surgical myectomy
  • Alcohol septal ablation 1, 2
• Septal reduction therapy should only be performed by experienced operators in comprehensive HCM clinical programs 1
• For patients with extensive apical hypertrophy extending to the midventricle who have refractory symptoms, transapical myectomy may be considered 3

Important Pitfalls to Avoid

• Do not perform septal reduction therapy in asymptomatic patients with normal exercise capacity, regardless of gradient severity 1, 2
• Verapamil can cause serious adverse effects in HCM patients with pulmonary edema, severe left ventricular outflow obstruction, or history of left ventricular dysfunction 4
• Careful monitoring is needed when combining medications, particularly when adding disopyramide, which should not be used alone in patients with atrial fibrillation 2