Hypertrophic Cardiomyopathy Clinical Practice Guidelines (AHA/ACC, 2020)

American Heart Association/American College of Cardiology

This is a quick summary of the guidelines without analysis or commentary. For more information, go directly to the guidelines by clicking the link in the reference.

January 28, 2021

In December 2020, the American Heart Association/American College of Cardiology (AHA/ACC) released clinical practice guidelines on the diagnosis and management of hypertrophic cardiomyopathy.[1]

Diagnosis

It is recommended that, as part of the initial diagnostic assessment in patients with suspected hypertrophic cardiomyopathy (HCM), a comprehensive physical examination and a complete medical and three-generation family history be performed.

Echocardiography

It is recommended that a transthoracic echocardiogram (TTE) be performed in the initial evaluation of patients with suspected HCM.

Repeat TTE is recommended every 1-2 years to evaluate the degree of myocardial hypertrophy, dynamic left ventricular (LV) outflow tract obstruction (LVOTO), mitral regurgitation (MR), and myocardial function, in patients with HCM who have experienced no change in clinical status or events.

Repeat TTE is recommended in patients with HCM in whom a change in clinical status or new clinical event has occurred.

A TTE with provocative maneuvers is recommended for patients with HCM who have a resting LV outflow tract (LVOT) gradient below 50 mmHg.

It is recommended that exercise TTE be performed for the detection and quantification of dynamic LVOTO in symptomatic patients with HCM in whom the resting or provokable outflow tract gradient is below 50 mmHg on TTE.

Intraoperative transesophageal echocardiogram (TEE) is recommended to evaluate mitral valve anatomy and function and the adequacy of septal myectomy, in patients with HCM in whom surgical septal myectomy is being performed.

TTE or intraoperative TEE, with intracoronary ultrasonogram-enhancing contrast injection of the septal perforator(s), is recommended for patients with HCM in whom alcohol septal ablation is being performed.

TTE within 3-6 months after septal reduction therapy (SRT) is recommended to assess the results in patients with HCM who have undergone the procedure.

Cardiovascular MRI

Cardiovascular magnetic resonance imaging (MRI) is indicated to clarify the diagnosis when, in patients suspected of having HCM, echocardiography is inconclusive.

Cardiovascular MRI is useful for patients with LV hypertrophy (LVH) when an alternative diagnosis such as infiltrative or storage disease or athlete's heart is suspected.

Cardiovascular MRI is a beneficial means of evaluating for maximum LV wall thickness, ejection fraction (EF), LV apical aneurysm, and the extent of myocardial fibrosis with late gadolinium enhancement (LGE), in patients who have not otherwise been identified as being at high SCD risk or in whom a decision to employ an implantable cardioverter-defibrillator (ICD) remains uncertain after a clinical assessment that includes personal/family history, echocardiography, and ambulatory electrocardiographic monitoring.

Cardiovascular MRI is indicated to inform the selection and planning of SRT when, in patients with obstructive HCM, the anatomic mechanism of obstruction is inconclusive on echocardiography.

Heart Rhythm Evaluation

It is recommended that in their initial evaluation (and as part of periodic follow-up, every 1-2 years) patients with HCM undergo a 12-lead electrocardiogram (ECG).

To identify individuals at SCD risk and guide arrhythmia management, it is recommended that patients with HCM undergo 24- to 48-hour ambulatory electrocardiographic monitoring during their initial evaluation and as part of periodic follow-up (every 1-2 years).

It is recommended that patients with HCM who develop palpitations or lightheadedness undergo extended (>24 hours) electrocardiographic monitoring or event recording. Unless symptoms occur during monitoring, this should not be considered diagnostic.

It is recommended that first-degree relatives of patients with HCM undergo a 12-lead ECG as part of the screening algorithm.

Angiography and Invasive Hemodynamic Evaluation

It is recommended that invasive hemodynamic assessment with cardiac catheterization be employed in patients with HCM who are candidates for SRT and in whom the results of noninvasive imaging studies are uncertain regarding the presence or severity of LVOTO.

It is recommended that coronary angiography (computed tomography [CT] or invasive) be performed in patients with HCM who have symptoms or evidence of myocardial ischemia.

When there is a risk of coronary atherosclerosis, it is recommended that patients with HCM undergo coronary angiography (CT or invasive) prior to surgical myectomy.

Exercise Stress Testing

Exercise TTE is recommended for the detection and quantification of dynamic LVOTO in patients with HCM who are symptomatic and who lack a resting or provokable outflow gradient of 50 mmHg or above on TTE.

Patients with nonobstructive HCM and advanced heart failure (HF) (New York Heart Association [NYHA] functional class III to class IV despite guideline-directed management and therapy [GDMT]) should undergo cardiopulmonary exercise stress testing to quantify the degree of functional limitation and to help select patients for heart transplantation or mechanical circulatory support.

Family Screening

It is recommended that part of the initial assessment of patients with HCM consist of assessment of familial inheritance, including a three-generation family history.

Genotype-Positive, Phenotype-Negative Patients

It is recommended that patients who are genotype-positive, phenotype-negative for HCM undergo serial clinical assessment, electrocardiography, and cardiac imaging at periodic intervals according to age (every 1-2 years in children and adolescents; every 3-5 years in adults) and clinical status change.


SCD Risk Evaluation

It is recommended that a comprehensive, systematic, noninvasive SCD risk assessment be performed on patients with HCM at initial evaluation and every 1-2 years thereafter, with assessment of the following risk factors included:

  • Personal history of cardiac arrest or sustained ventricular arrhythmias

  • Personal history of syncope that, owing to clinical history, is suspected of being arrhythmic

  • Family history of premature, HCM-related sudden death; cardiac arrest; or sustained ventricular arrhythmias, in a close relative

  • Maximal LV wall thickness, EF, LV apical aneurysm

  • Episodes of nonsustained ventricular tachycardia (NSVT) on continuous ambulatory electrocardiographic monitoring

Cardiovascular MRI is beneficial for the evaluation of maximum LV wall thickness, EF, LV apical aneurysm, and extent of myocardial fibrosis with LGE, in patients with HCM who have not otherwise been identified as being at high SCD risk or in whom it is still not certain after clinical assessment—including evaluation of personal/family history, echocardiography, and ambulatory electrocardiographic monitoring—whether ICD placement should proceed.

ICDs

It is recommended that an ICD be placed in patients with HCM and previous, documented cardiac arrest or sustained ventricular tachycardia (VT)

Single-coil, rather than dual-coil, ICD leads are recommended in patients with HCM who are receiving an ICD.

Management of HCM

It is recommended that nonvasodilating beta blockers, titrated to effectiveness or maximally tolerated doses, be used in patients with obstructive HCM and symptoms attributable to LVOTO.

It is recommended that non-dihydropyridine calcium channel blockers (eg, verapamil, diltiazem) be substituted for beta blockers in patients with obstructive HCM and symptoms attributable to LVOTO, if beta blockers are ineffective or not tolerated.

If, despite the use of beta blockers or non-dihydropyridine calcium channel blockers, patients with obstructive HCM have persistent, severe symptoms attributable to LVOTO, it is recommended either that disopyramide be added to treatment with one of the other drugs or that SRT be performed at an experienced center.

It is recommended that intravenous phenylephrine (or other vasoconstrictors without inotropic activity) be used alone or in combination with beta-blocking drugs if patients with obstructive HCM and acute hypotension are not responsive to fluid administration.

If performed at an experienced center, it is recommended that in eligible patients, SRT be employed to relieve LVOTO when individuals with obstructive HCM remain severely symptomatic despite GDMT.

If performed at an experienced center, it is recommended that surgical myectomy be employed in symptomatic patients with obstructive HCM who have associated cardiac disease requiring surgery (eg, associated anomalous papillary muscle, markedly elongated anterior mitral leaflet, intrinsic mitral valve disease, multivessel coronary artery disease [CAD], valvular aortic stenosis).

If performed at an experienced center, it is recommended that alcohol septal ablation be employed in eligible adult patients with obstructive HCM who remain severely symptomatic, despite GDMT, and in whom surgery is contraindicated or poses an unacceptable risk owing to serious comorbidities or advanced age.

It is recommended that patients with nonobstructive HCM with preserved EF and symptoms of exertional angina or dyspnea be treated with beta blockers or non-dihydropyridine calcium channel blockers.

It is recommended that anticoagulation with direct-acting oral anticoagulants (DOAC; as a first-line option) and vitamin K antagonists (as a second-line option) be employed, independent of the CHA2DS2-VASc score, in patients with HCM and clinical atrial fibrillation (AF).

It is recommended that anticoagulation be performed with DOAC (as a first-line option) and vitamin K antagonists (as a second-line option), independent of the CHA2DS2-VASc score, in patients with HCM in whom subclinical AF has been detected by internal or external cardiac device or monitor of over 24 hours' duration for a given episode.

It is recommended that beta blockers, verapamil, or diltiazem be used in individuals with AF in whom a rate-control strategy is planned, with the specific agent being chosen according to patient preferences and comorbid conditions.

Assessment for heart transplantation, in accordance with current listing criteria, is indicated in patients with HCM and recurrent, poorly tolerated, life-threatening ventricular tachyarrhythmias that have proven refractory to maximal antiarrhythmic drug therapy and ablation.

It is recommended that antiarrhythmic drug therapy be used in adults with HCM who have symptomatic ventricular arrhythmias or recurrent ICD shocks despite beta-blocker use. The agent should be chosen based on factors such as age, underlying comorbidities, severity of disease, patient preferences, and the balance between efficacy and safety.

It is recommended that antiarrhythmic drug therapy (amiodarone, mexiletine, sotalol) be used in children with HCM who have recurrent ventricular arrhythmias despite beta-blocker use. The agent should be chosen based on factors such as age, underlying comorbidities, severity of disease, patient preferences, and the balance between efficacy and safety.

It is recommended that in patients with HCM who have a pacing-capable ICD, shock risk be minimized by programming antitachycardia pacing into the device.

It is recommended that guideline-directed therapy for HF with reduced EF be employed in patients with HCM who develop systolic dysfunction with an LVEF below 50%.

It is recommended that diagnostic testing be carried out in patients with HCM and systolic dysfunction to evaluate for concomitant causes of systolic dysfunction (such as CAD).

Patients with nonobstructive HCM and advanced HF (NYHA functional class III to class IV despite guideline-directed therapy) should undergo a cardiopulmonary exercise test (CPET) to quantify the degree of functional limitation and to help in patient selection for heart transplantation or mechanical circulatory support.

It is recommended that evaluation for heart transplantation be carried out in accordance with current listing criteria when patients with nonobstructive HCM have advanced HF (NYHA class III to class IV despite guideline-directed therapy) or when life-threatening ventricular arrhythmias are refractory to maximal guideline-directed therapy.

Lifestyle Considerations

Mild- to moderate-intensity recreational exercise is beneficial in most patients with HCM as a means of improving cardiorespiratory fitness, physical functioning, and quality of life, and as a strategy for aiding overall health, in keeping with physical activity guidelines for the general population.

It is recommended that, via an expert provider, athletes with HCM undergo a comprehensive evaluation and participate in a shared discussion of the potential risks of sports participation.

Pregnancy

As a means of stroke prevention in pregnant women with HCM and AF or other indications for anticoagulation, administration of low–molecular-weight heparin or vitamin K antagonists (at maximum therapeutic dose of <5 mg daily) is recommended.

Selected beta blockers should be administered to pregnant women with HCM for symptoms associated with outflow tract obstruction or arrhythmias, with monitoring of fetal growth.

It is recommended that vaginal delivery be the first-choice delivery option in the majority of pregnant women with HCM.

The option of preconceptional and prenatal reproductive and genetic counseling should be given to affected families with HCM.

The patient's cardiologist and obstetrician should coordinate care for a pregnant woman with HCM. It is advised that pregnant individuals with HCM who are deemed high risk consult with an expert in maternal-fetal medicine.

Comorbidities

To decrease the risk of cardiovascular events, it is recommended that patients with HCM adhere to the guidelines on the prevention of atherosclerotic cardiovascular disease.

Counseling and comprehensive lifestyle interventions are recommended for patients with HCM who are overweight or obese, as a means of losing weight and maintaining this reduction and as a strategy for possibly lowering the risk of developing LVOTO, HF, and AF.

Lifestyle modifications and medical therapy for hypertension are recommended for individuals with HCM and hypertension, with beta blockers and non-dihydropyridine calcium channel blockers being preferred in patients with obstructive HCM.

It is recommended that patients with HCM be evaluated for symptoms of sleep-disordered breathing. If such symptoms are present, the patient should be referred to a sleep medicine specialist for assessment and treatment.

For more information, please go to Hypertrophic Cardiomyopathy.

For more Clinical Practice Guidelines, please go to Guidelines.

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