Hypertrophic Cardiomyopathy: A 2020 AHA/ACC Guideline for Patient Management

A new guideline for diagnosing and managing patients with hypertrophic cardiomyopathy (HCM) focuses on shared decision-making between clinicians and patients to personalize treatment options.

The 2020 guideline, issued by the American Heart Association (AHA) and the American College of Cardiology (ACC) and published jointly in Circulation and the Journal of the American College of Cardiology, provides an update to the previous guideline published in 2011. It addresses the comprehensive evaluation and management of adults and children with HCM and was developed for cardiovascular and noncardiovascular clinicians.

What Is the Range of New Recommendations?

New recommendations address such topics as electrocardiography, imaging and genetic testing, medical therapies, septal reduction therapies (SRT), sudden cardiac death (SCD) risk assessment and prevention, and lifestyle considerations, including participation in activities and sports, occupation, and pregnancy.

Shared decision-making between patients and providers can lead to better health outcomes, and the best opportunities involve those in which complex pathways can vary among different patients, according to the AHA/ACC writing committee.

“For patients with HCM or at risk for HCM, shared decision-making is recommended in developing a plan of care (including but not limited to decisions regarding genetic evaluation, activity, lifestyle, and therapy choices) that includes a full disclosure of the risks, benefits, and anticipated outcomes of all options, as well as the opportunity for the patient to express [his or her] goals and concerns,” the committee recommended.

Specialized needs, complex and evolving clinical management, and the relatively uncommon prevalence of HCM in many clinical practices have created a greater demand for clinical HCM centers, according to the writing committee.

“In patients with HCM in whom SRT is indicated, the procedure should be performed at experienced centers (comprehensive or primary HCM centers) with demonstrated excellence in clinical outcomes for these procedures,” the committee advised. “In patients with HCM, consultation with or referral to a comprehensive or primary HCM center is reasonable to aid in complex disease-related management decisions.”

Implications for Diagnosis and Decision-Making

Cardiac imaging has an important role in the diagnosis and clinical decision-making in patients with HCM. Echocardiography is the primary imaging modality, and cardiovascular magnetic resonance (CMR) imaging may be an alternative to echocardiography when the echocardiogram is inconclusive, noted the committee.

“In patients with suspected HCM, a transthoracic echocardiogram (TTE) is recommended in the initial evaluation,” the writing committee stated. “In patients with HCM with no change in clinical status or events, repeat TTE is recommended every 1 to 2 years to assess the degree of myocardial hypertrophy, dynamic left ventricular outflow tract obstruction (LVOTO), mitral regurgitation, and myocardial function. For patients with HCM who experience a change in clinical status or a new clinical event, repeat TTE is recommended.”

Cardiac computed tomography (CT) provides excellent spatial resolution that allows for clear definition of LV structure, according to the writing committee. “In adult patients with suspected HCM, cardiac CT may be considered for diagnosis if the echocardiogram is not diagnostic and CMR imaging is unavailable,” the group recommended.

Other Key Factors for Assessment

Genetic testing has an important role in diagnosing and managing patients with HCM, as well as for their families. Ideally, genetic assessment should be performed in a specialized multidisciplinary HCM center experienced in all aspects of genetic counseling and testing, noted the writing committee. “In patients with HCM, evaluation of familial inheritance, including a 3-generation family history, is recommended as part of the initial assessment,” the committee advised.

Younger patients with HCM have a higher risk for SCD compared with older patients. Because the risk of SCD extends for many years, periodic reassessment of this risk is an integral component of evaluating most patients with HCM, noted the writing committee.

“In patients with HCM, a comprehensive, systematic noninvasive SCD risk assessment at initial evaluation and every 1 to 2 years thereafter is recommended and should include evaluation of these risk factors: (a) Personal history of cardiac arrest or sustained ventricular arrhythmias. (b) Personal history of syncope suspected by clinical history to be arrhythmic. (c) Family history in close relative of premature HCM-related sudden death, cardiac arrest, or sustained ventricular arrhythmias. (d) Maximal LV wall thickness, ejection fraction (EF), LV apical aneurysm. (e) [nonsustained ventricular tachycardia (NSVT)] episodes on continuous ambulatory electrocardiographic monitoring.”

Primary Goals of Pharmacologic Therapy

The main role of pharmacologic therapy aimed at the dynamic left ventricular obstruction is symptom relief because no convincing data suggest that pharmacologic therapy alters the natural history of HCM, according to the writing committee. “In patients with obstructive HCM and symptoms attributable to LVOTO, nonvasodilating beta-blockers, titrated to effectiveness or maximally tolerated doses, are recommended,” stated the committee. “In patients with obstructive HCM and symptoms attributable to LVOTO, for whom beta-blockers are ineffective or not tolerated, substitution with non-dihydropyridine calcium channel blockers (eg, verapamil, diltiazem) is recommended.”

SRT is generally reserved for patients with symptoms that are not relieved by medical therapy and affect the quality of life, noted the writing committee. “In patients with obstructive HCM who remain severely symptomatic despite guideline-directed management and therapy, SRT in eligible patients, performed at experienced centers, is recommended for relieving LVOTO,” the committee advised.

Symptomatic, nonobstructive HCM can be a diagnostic and therapeutic challenge, according to the writing committee. “In patients with nonobstructive HCM with preserved EF and symptoms of exertional angina or dyspnea, beta-blockers or non-dihydropyridine calcium channel blockers are recommended,” the committee advised.

Implications for Managing Patients

Recommendations for recreational exercise and competitive sports participation for patients with HCM have been challenging, and available data regarding the risk of SCD in this population are inconsistent, noted the writing committee.

“For most patients with HCM, mild- to moderate-intensity recreational exercise is beneficial to improve cardiorespiratory fitness, physical functioning, and quality of life, and for their overall health in keeping with physical activity guidelines for the general population,” the committee advised. “For athletes with HCM, a comprehensive evaluation and shared discussion of potential risks of sports participation by an expert provider is recommended. For most patients with HCM, participation in low-intensity competitive sports is reasonable.”

Patients with HCM also have a number of occupational considerations, particularly those involving potential loss of consciousness that can place the patient or others in a harmful situation. “For patients with HCM, it is reasonable to follow Federal Motor Carrier Safety Administration cardiovascular disease guidelines that permit driving commercial motor vehicles, if they do not have an implantable cardioverter-defibrillator (ICD) or any major risk factors for SCD and are following a guideline-directed management plan,” advised the writing committee.

Pregnancy in most women with HCM is well tolerated, and maternal mortality is very low, according to the committee. “For pregnant women with HCM and atrial fibrillation or other indications for anticoagulation, low-molecular-weight heparin or vitamin K antagonists (at maximum therapeutic dose of <5 mg daily) are recommended for stroke prevention,” the committee advised. “In pregnant women with HCM, selected beta-blockers should be administered for symptoms related to outflow tract obstruction or arrhythmias, with monitoring of fetal growth.”

AHA/ACC Top 10 Take-Home Messages for Managing Patients With HCM

1. Shared decision-making, a dialogue between patients and their care team that includes full disclosure of all testing and treatment options, discussion of the risks and benefits of those options, and, importantly, engagement of the patient to express his or her own goals, is particularly relevant in the management of conditions such as HCM.

2. Although the primary cardiology team can initiate evaluation, treatment, and longitudinal care, referral to multidisciplinary HCM centers with graduated levels of expertise can be important to optimizing care for patients with HCM. Challenging treatment decisions—in which reasonable alternatives exist, the strength of recommendation is weak (eg, any class 2b decision) or is particularly nuanced, and for invasive procedures that are specific to patients with HCM—represent crucial opportunities to refer patients to these HCM centers.

3. Counseling patients with HCM regarding the potential for genetic transmission of HCM is one of the cornerstones of care. Screening first-degree family members of patients with HCM, using either genetic testing or an imaging/electrocardiographic surveillance protocol, can begin at any age and can be influenced by specifics of the patient/family history and family preference. As screening recommendations for family members hinge on the pathogenicity of any detected variants, the reported pathogenicity should be reconfirmed every 2 to 3 years.

4. Optimal care for patients with HCM requires cardiac imaging to confirm the diagnosis, characterize the pathophysiology for the individual, and identify risk markers that may inform decisions regarding interventions for left ventricular outflow tract obstruction and SCD prevention. Echocardiography continues to be the foundational imaging modality for patients with HCM. CMR imaging will also be helpful in many patients, especially those in whom there is diagnostic uncertainty, poor echocardiographic imaging windows, or when uncertainty persists regarding decisions about ICD placement.

5. Assessment of an individual patient’s risk for SCD continues to evolve as new markers emerge (eg, apical aneurysm, decreased left ventricular systolic function, and extensive gadolinium enhancement). In addition to a full accounting of an individual’s risk markers, communication with patients regarding not just the presence of risk markers but also the magnitude of their individualized risk is key. This enables informed patients to fully participate in the decision-making regarding ICD placement, which incorporates their own level of risk tolerance and treatment goals.

6. The risk factors for SCD in children with HCM carry different weights than those observed in adult patients; they vary with age, and different body sizes must be accounted for. Coupled with the complexity of placing ICDs in young patients with anticipated growth and a higher risk of device complications, the threshold for ICD implantation in children often differs from that for adults. These differences are best addressed at primary or comprehensive HCM centers with expertise in children with HCM.

7. Septal reduction therapies (surgical septal myectomy and alcohol septal ablation), when performed by experienced HCM teams at dedicated centers, continue to improve in safety and efficacy such that earlier intervention may be possible in select patients with drug-refractory or severe outflow tract obstruction causing signs of cardiac decompensation. Given the data on the significantly improved outcomes at comprehensive HCM centers, these decisions represent an optimal referral opportunity.

8. Patients with HCM and persistent or paroxysmal atrial fibrillation have a sufficiently increased risk of stroke such that oral anticoagulation with direct oral anticoagulants (or alternatively, warfarin) should be considered the default treatment option independent of the CHA₂ DS₂ VASc score. As rapid atrial fibrillation is often poorly tolerated in patients with HCM, maintenance of sinus rhythm and rate control are key pursuits in successful treatment.

9. Heart failure symptoms in patients with HCM, in the absence of left ventricular outflow tract obstruction, should be treated similarly to other patients with heart failure symptoms, including consideration of advanced treatment options (eg, cardiac resynchronization therapy, left ventricular assist device, transplantation). In patients with HCM, an ejection fraction of less than 50% connotes significantly impaired systolic function and identifies individuals with poor prognosis and who are at increased risk for SCD.

10. Increasingly, data affirm that the beneficial effects of exercise on general health can be extended to patients with HCM. Healthy recreational exercise (moderate intensity) has not been associated with increased risk of ventricular arrhythmia events in recent studies. Whether an individual patient with HCM wishes to pursue more rigorous exercise or training depends on a comprehensive shared discussion between that patient and his or her expert HCM care team regarding the potential risks of that level of training or participation but with the understanding that exercise-related risk cannot be individualized for a given patient.

The writing committee consisted of clinicians, cardiologists, interventionalists, cardiovascular surgeons, and a lay/patient representative and included representatives from the ACC, AHA, American Association for Thoracic Surgery, American Society of Echocardiography, Heart Failure Society of America, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance.

The guideline was developed in collaboration with and endorsed by the American Association for Thoracic Surgery, American Society of Echocardiography, Heart Failure Society of America, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, and Society for Cardiovascular Magnetic Resonance; it was endorsed by the Pediatric and Congenital Electrophysiology Society.

Disclosures: Some of the writing committee members reported affiliations with pharmaceutical and medical device companies. Please see the original reference for a full list of authors’ disclosures.

References

1. Ommen SR, Mital S, Burke MA, et al. 2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Published online November 20, 2020. Circulation. doi: 10.1161/CIR.0000000000000938

2. Writing Committee Members; Ommen SR, Mital S, Burke MA, et al. 2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients with Hypertrophic Cardiomyopathy: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Published online November 20, 2020. J Am Coll Cardiol. doi: 10.1016/j.jacc.2020.08.044