2024 AHA/ACC/Multisociety Hypertrophic Cardiomyopathy Guideline: Key Points

Ommen SR, Ho CY, Asif IM, et al.
2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines. J Am Coll Cardiol 2024;May 8:[Epub ahead of print].

The following are key points to remember from the 2024 AHA/ACC/multisociety guideline for the management of hypertrophic cardiomyopathy (HCM):

  1. Patients with HCM should be engaged in shared decision making to develop a care plan. Multidisciplinary HCM centers can help confirm diagnosis, facilitate genetic testing, and help guide advanced treatment options such as septal reduction therapies (SRTs).
  2. All patients being evaluated for HCM should have a comprehensive physical exam, medical history, and a three-generation family history assessed. Associated systemic or extracardiac symptoms should also be assessed to rule out HCM phenocopies (Danon, Fabry, RASopathies) as well as alternative causes for hypertrophy including hypertension, renal disease, valvular disease, and infiltrative diseases.
  3. In patients with HCM, a transthoracic echocardiogram (TTE) is recommended in initial evaluation. This should be repeated every 1-2 years or sooner if there are changes in clinical status. If the resting gradient is <50 mm Hg, provocative maneuvers (e.g., Valsalva) are recommended. In the absence of a provocable gradient, an exercise TTE is recommended.
  4. For screening of family members, TTE is recommended initially and should be repeated if clinical status changes or in children every 1-2 years and adults every 3-5 years.
  5. A cardiac magnetic resonance imaging (MRI) can be considered if TTE is inconclusive in HCM diagnosis and in SRT pre-procedure planning. Cardiac MRI can also help exclude infiltrative disease as well as athlete’s heart and help with sudden cardiac death (SCD) risk stratification when an implantable cardioverter-defibrillator (ICD) is not clearly indicated after clinical assessment.
  6. In all HCM patients, a 12-lead electrocardiogram (ECG) should be included in initial and annual follow-up assessments with 24-48 hours of ambulatory ECG monitoring for SCD risk stratification. In symptomatic patients with palpitations or in patients at high risk for atrial fibrillation (AF), an extended ECG monitor should be considered.
  7. For symptomatic HCM patients when location and severity of left ventricular (LV) outflow tract obstruction cannot be accurately assessed, a cardiac catheterization for invasive hemodynamic assessment is recommended. Similarly, coronary angiography should be performed prior to SRT and for symptoms of angina.
  8. For HCM patients, evaluation by a genetic counselor is recommended to discuss risk and benefits of genetic testing. HCM genetic testing should include genes for HCM phenocopies. Cascade genetic testing should be extended to first-degree relatives only if a pathogenic variant is identified in the proband. Preconception and prenatal genetic counseling should be offered to afflicted families.
  9. Family members who are genotype positive, but phenotype negative may participate in competitive sports. An ICD is not recommended for these family members for primary prevention and is not recommended for solely permitting participation in sport.
  10. For adolescent and adult HCM patients, risk stratification for SCD should be performed every 1-2 years. This assessment should include personal history of cardiac arrest or ventricular arrhythmias, arrhythmogenic syncope, family history of premature SCD, maximal LV thickness, LV apical aneurysm, and nonsustained ventricular tachycardia (VT) on ambulatory ECG monitoring. An ICD is indicated with previous VT or cardiac arrest in HCM patients.
  11. For symptomatic obstructive HCM patients, the first line of treatment is non-vasodilating beta-blockers. If these are not tolerated/ineffective, non-dihydropyridine calcium channel blockers (diltiazem/verapamil) should be considered. Verapamil is contraindicated however with rest symptoms, hypotension, and very high gradients of >100 mm Hg at rest. Use of combination therapy with both beta-blocker and calcium channel blocker is unsupported for HCM. In the event of persistent symptoms despite trial of both classes, either addition of myosin inhibitors in adults, disopyramide, or SRTs should be considered.
  12. SRTs must be performed at experienced HCM centers. Myectomy is recommended if there is an associated cardiac disease needing surgical treatment (e.g., mitral valve abnormalities). If surgery is contraindicated, alcohol septal ablation can be considered.
  13. For HCM patients with LVEF <50%, standard guideline-directed medical therapy for heart failure with reduced ejection fraction (HFrEF) is recommended with discontinuation of myosin inhibitors and assessment for other causes for HFrEF such as coronary artery disease. Heart transplantation should be considered in patients with nonobstructive HCM and advanced HF or with arrhythmia refractory to therapy.
  14. In HCM patients with clinical AF or subclinical AF of >24 hours’ duration, irrespective of CHA2DS2-VASc score, systemic anticoagulation is recommended with a direct-acting oral anticoagulant (DOAC) as first line and vitamin K antagonist as second line.
  15. HCM patients should be encouraged to participate in mild to moderate intensity recreational exercise. Athletes with HCM should engage in shared decision making regarding sport participation. Universal restriction from competitive sports in HCM patients is not indicated.
  16. Pregnant women with HCM on beta-blockers should be monitoring for arrhythmias and symptoms. Vaginal delivery is recommended, and care should be coordinated between their cardiologist and an obstetrician. Mavacamten is teratogenic and should not be used.

Clinical Topics: Arrhythmias and Clinical EP, Noninvasive Imaging, Atrial Fibrillation/Supraventricular Arrhythmias, Echocardiography/Ultrasound, Heart Failure and Cardiomyopathies

Keywords: Atrial Fibrillation, Echocardiography, Hypertrophic Cardiomyopathy

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