Hypertrophic Cardiomyopathy Treatment: An Individualized Approach

November 23, 2022|PCNA

Putting the pieces together of CVD diagnosis and treatment plan requires an individualized approach—and hypertrophic cardiomyopathy (HCM) is no exception.

Hypertrophic Cardiomyopathy Prevalence and Diagnosis

HCM is the most common genetic heart disease in the United States, with one in 500 or 0.2% diagnosed with the condition worldwide. HCM causes thickening of the left ventricle which reduces the heart’s ability to pump blood efficiently; in severe cases, there is obstruction of blood flow to the body.

Diagnosis can be complicated due to symptom variability and similarity to other health conditions such as exercise-induced asthma. Some individuals are asymptomatic; other individuals have severe symptoms and complications—often during exertion. For more details about symptomology and diagnosis, check out this PCNA’s Heart to Heart Nurse podcast episode.

Hypertrophic Cardiomyopathy Treatment: Pharmacological, Medical, and Surgical

Once the HCM diagnosis is confirmed, the process for disease management begins and may entail both medical and surgical options. The 2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy[1] provides guidance including consideration of factors such as patient age, presence or absence of left ventricular outflow obstruction (LVOTO), left ventricular ejection fraction, hypotension, atrial and ventricular arrhythmias, risk of sudden cardiac death (SCD), and others.

Some of the recommendations include the following. Always refer to the latest professional guidelines, best practices, institutional policies, and the specific circumstances of the individual being treated to identify the best course of action. The use of shared decision-making (SDM) enables patients to take an active role in their treatment, which can lead to improved adherence and outcomes.

Pharmacotherapies

There are a number of algorithms within the AHA/ACC Guideline Document that can support clinicians in applying the recommendations for medical therapies for HCM symptom management and risk reduction for future cardiac events.

Treating comorbidities is a key first step, regardless of symptomology.

For persistent paroxysmal atrial fibrillation, regardless of CHA2DS2VASc score, it is recommended that direct oral anticoagulants (DOACs) be used.

For individuals with LVOTO, the following recommendations are included to optimize hemodynamics and manage symptoms:

  • Nonvasodilating beta-blockers
    • Use nondihydropyridine calcium channel blockers if beta-blockers are not tolerated or are ineffective
  • Verapamil or diltiazem
  • If severe symptoms still persist, addition of disopyramide

For patients with obstruction, the guideline includes a class 1 endorsement of vasoconstrictors without inotropic activity—either alone or with beta-blockers—for acute hypotension which is unresponsive to the administration of fluids. A class 2b recommendation offers cautious use of low-dose diuretics for patients experiencing persistent dyspnea, along with volume overload and high left-sided filling pressures.

For patients with obstructive HCM that have severe dyspnea at rest, hypotension, resting gradients over 100 mm Hg, or are less than 6 weeks of age, the discontinuation of vasodilators and digoxin was considered reasonable, and verapamil was noted as potentially harmful.

While not yet included in the guideline, in April of 2022 the FDA approved the first-in-class drug, mavacamten, which is a cardiac myosin inhibitor for the treatment of obstructive HCM in individuals with NYHA class II-III symptoms. There are specific indications for use under a risk evaluation and mitigation strategy (REMS) program to ensure adequate ejection fraction for patients.[2] The medication can offer better functional capacity and improved quality of life.

Medical and Surgical Therapies

For those patients for whom medication is ineffective, still have severe symptoms, or are not good surgical candidates due to complicating comorbidities, additional therapeutic options are available.

Alcohol Septal Ablation: This non-surgical procedure utilizes a balloon-tip catheter. The catheter is threaded through a blood vessel in the groin to the septum of the heart, where alcohol is injected into the thickened heart muscle. Some of the cardiac cells shrink and die; the scarred tissue is less thick and allows improved blood flow. There are risks for complications, such as the need for a pacemaker after the procedure due to heart block, a disruption of electrical signals through the heart which can reduce cardiac rhythm.

Septal Myectomy: A surgeon removes excess cardiac muscle from the thickened septum. This open-heart surgery includes a longer recovery time than an alcohol septal ablation, and some medical conditions may increase the risk for this type of procedure. If patients have other heart abnormalities that require repair, myectomy may be preferable to ablation.

Implantable Cardioverter Defibrillator (ICD) Therapy: In patients with HCM, risk stratification and selection of patients for prophylactic ICD therapy is an evolving process. The placement of an ICD can save the lives of some patients by aborting potentially life-threatening ventricular tachyarrythmias. Using the guideline recommendations and associated algorithms to identify patients at greatest risk, and using an SDM process to balance the risks and benefits, can be helpful in this complex ICD decision-making process.

Hypertrophic Cardiomyopathy Treatment is a Team Effort

In concert with a patient’s local team of primary care, cardiology, and other specialty providers, staff at an HCM Center of Excellence (CoE) provide support and resources to healthcare professionals (HCPs), patients, and families affected by HCM. While CoEs may vary in scope and services, they provide expertise in HCM, high-quality care for patients and families, second opinions for both HCPs and patients, and may even include research opportunities in-house or through referral networks.

Hypertrophic Cardiomyopathy Resources

From PCNA:

Hypertrophic Cardiomyopathy Association: information for providers, patients, and about HCM Centers of Excellence.

[1] Ommen SR, Mital S, Burke MA, et al. 2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy. Circulation. 2020;142:e558-e631. https://doi.org/10.1161/CIR.0000000000000937

[2] Lou, Nicole. Cardiac Myosin Inhibitor Gets FDA’s Blessing for Obstructive HCM. MedPage Today. April 29, 2022. https://www.medpagetoday.com/cardiology/prevention/98464. Accessed October 26, 2022.

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