What are the treatment options for Hypertrophic Cardiomyopathy (HCM) and associated complications?

From the Guidelines

The treatment for hypertrophic cardiomyopathy (HCM) should prioritize a multidisciplinary approach, incorporating shared decision-making, genetic counseling, and risk stratification for sudden cardiac death, with first-line medical therapy typically involving beta-blockers or non-dihydropyridine calcium channel blockers, and consideration of septal reduction therapy or implantable cardioverter-defibrillator placement as needed 1.

Key Considerations

• The primary goal of treatment is to alleviate symptoms and prevent complications, with a focus on individualized care and patient-centered decision-making 1.
• Beta-blockers, such as metoprolol, and non-dihydropyridine calcium channel blockers, like verapamil, are commonly used as first-line medical therapy to reduce heart rate, improve diastolic filling, and decrease outflow obstruction 1.
• For patients with obstructive HCM who remain symptomatic despite optimal medical therapy, septal reduction therapy, either through surgical myectomy or alcohol septal ablation, may be considered, with referral to specialized HCM centers recommended for optimal outcomes 1.
• Cardiac myosin inhibitors, such as mavacamten, offer a new treatment option for patients with symptomatic obstructive HCM who do not derive adequate symptomatic relief from first-line drug therapy 1.
• Patients with HCM and persistent or paroxysmal atrial fibrillation should be considered for oral anticoagulation with direct-acting oral anticoagulants or warfarin, regardless of CHADS2-VASc score, to mitigate the increased risk of stroke 1.

Complications and Risks

• Medical therapy may be associated with complications, such as bradycardia, hypotension, fatigue, and anticholinergic effects, which should be carefully monitored and managed 1.
• Surgical myectomy and alcohol septal ablation carry risks, including ventricular septal defect, aortic regurgitation, complete heart block, and perioperative mortality, emphasizing the need for careful patient selection and referral to experienced HCM teams 1.

Genetic Counseling and Risk Stratification

• Genetic counseling is essential for patients with HCM, given the condition's autosomal dominant inheritance, and should include discussion of genetic testing options and screening recommendations for first-degree family members 1.
• Risk stratification for sudden cardiac death is critical, incorporating established risk markers and individual risk score estimation to inform decision-making regarding implantable cardioverter-defibrillator placement 1.

From the FDA Drug Label

In 120 patients with hypertrophic cardiomyopathy (most of them refractory or intolerant to propranolol) who received therapy with verapamil at doses up to 720 mg/day, a variety of serious adverse effects were seen Three patients died in pulmonary edema; all had severe left ventricular outflow obstruction and a past history of left ventricular dysfunction. Eight other patients had pulmonary edema and/or severe hypotension; abnormally high (greater than 20 mmHg) pulmonary wedge pressure and a marked left ventricular outflow obstruction were present in most of these patients Sinus bradycardia occurred in 11% of the patients, second-degree AV block in 4%, and sinus arrest in 2%. The combination of sustained-release verapamil and beta-adrenergic blocking agents has not been studied However, there have been reports of excessive bradycardia and AV block, including complete heart block, when the combination has been used for the treatment of hypertension. In patients with hypertrophic cardiomyopathy (IHSS), alpha-adrenergic agents (phenylephrine HCl, metaraminol bitartrate, or methoxamine HCl) should be used to maintain blood pressure, and isoproterenol and norepinephrine should be avoided

The treatment options for Hypertrophic Cardiomyopathy (HCM) and associated complications include:

• Verapamil: may be used to treat HCM, but with caution and close monitoring due to the risk of adverse effects such as pulmonary edema, hypotension, and AV block.
• Alpha-adrenergic agents: such as phenylephrine, metaraminol, or methoxamine, may be used to maintain blood pressure in patients with HCM.
• Avoidance of certain medications: such as beta-adrenergic blockers, isoproterenol, and norepinephrine, which may exacerbate HCM.
• Close monitoring: of patients with HCM, including monitoring of blood pressure, cardiac function, and potential adverse effects of medications 2.

From the Research

Treatment Options for Hypertrophic Cardiomyopathy (HCM)

• Medical management is the primary treatment approach for HCM, aiming to reduce symptoms and prevent sudden cardiac death (SCD) 3, 4.
• Pharmacologic treatment of symptoms in patients with HOCM consists of negative inotropic drugs, such as beta blockers and disopyramide, as well as nondihydropyridine calcium channel blockers (CCBs) like verapamil 3, 5.
• For patients with high left ventricular outflow tract (LVOT) gradients, treatment options include nonvasodilating beta-blockers or non-dihydropyridine-type CCBs, with mavacamten, a myosin inhibitor, being a newer option 5.
• Septal reduction therapies, including surgical septal myectomy and alcohol septal ablation, can be considered for patients with severe symptoms unresponsive to medical therapy 3, 6.

Septal Reduction Therapies

• Surgical septal myectomy is a highly effective treatment with a >90% relief of obstruction and improvement in symptoms, but it is typically offered to younger patients with extreme hypertrophy 6.
• Alcohol septal ablation is a less invasive treatment with comparable hemodynamic and clinical results to septal myectomy, but its effectiveness depends on the septal perforator artery supplying the area of contact between the hypertrophied septum and the anterior leaflet of the mitral valve 6.
• The choice between septal myectomy and alcohol septal ablation depends on patient preference, operator experience, and institutional availability 3, 6.

Management of Complications

• Patients with HCM are at risk of developing atrial fibrillation, malignant arrhythmias, and mitral valve insufficiency, which require careful management 5.
• Implantable cardioverter-defibrillators (ICDs) are recommended for patients at high risk of SCD 3.
• Regular screening of relatives is essential for early detection and treatment of HCM 3.