The American College of Cardiology and American Heart Association’s latest recommendations include a new drug class and low-to-moderate exercise.

Summary: The American College of Cardiology and the American Heart Association have released a new guideline for managing hypertrophic cardiomyopathy. The guidelines emphasize collaborative decision-making and recommend updated treatment pathways, including cardiac myosin inhibitors. It advocates for incorporating low-to-moderate intensity exercise and suggests vigorous physical activities can be reasonable for some individuals. The guidelines also provide recommendations for risk assessment of sudden cardiac death, especially in pediatric cases, and were created in collaboration with leading medical societies.

Key Takeaways: 

  • The new guideline recommends incorporating cardiac myosin inhibitors for symptomatic obstructive hypertrophic cardiomyopathy, offering an alternative for patients who have not responded to first-line therapies.
  • Low-to-moderate intensity exercise is now encouraged for all patients with hypertrophic cardiomyopathy, with some patients able to engage in competitive sports following shared decision-making with clinicians.
  • The new guideline provides recommendations for assessing and managing the risk of sudden cardiac death, emphasizing clear risk markers and patient-specific risk scores.

The American College of Cardiology and the American Heart Association released a new clinical guideline for managing individuals diagnosed with hypertrophic cardiomyopathy. 

The guideline reiterates the importance of collaborative decision-making with patients who have hypertrophic cardiomyopathy and provides updated recommendations for the most effective treatment pathways for adult and pediatric patients.

Hypertrophic cardiomyopathy is an inherited cardiac condition most often caused by a gene mutation that makes the heart muscle too thick (hypertrophy), which impairs its ability to adequately pump blood throughout the body. Hypertrophic cardiomyopathy affects approximately 1 in every 500 individuals; however, a significant portion of cases remain undiagnosed because many people do not exhibit symptoms. Occasionally, the first time hypertrophic cardiomyopathy is diagnosed is after a sudden death. People who do have symptoms may experience episodes of fainting, chest pain, shortness of breath, or irregular heartbeats.

Evidence-Based Guidance

“Incorporating the most recent data, this new guideline equips clinicians with the latest recommendations for the treatment of [hypertrophic cardiomyopathy],” said Steve R. Ommen, MD, FACC, medical director of the Mayo Hypertrophic Cardiomyopathy Clinic and chair of the guideline writing committee, in a release. “We’re seeing more evidence that patients with [hypertrophic cardiomyopathy] can return to their normal daily lives with proper care and management.”

Updated recommendations in the guideline reflect recent evidence about hypertrophic cardiomyopathy treatment and management including new forms of pharmacologic management; participation in vigorous recreational activities and competitive sports; and risk stratification for sudden cardiac death with an emphasis on pediatric patients.

Incorporating Cardiac Myosin Inhibitors

The guideline includes recommendations for adding cardiac myosin inhibitors, a new class of medication for patients with symptomatic obstructive hypertrophic cardiomyopathy who do not get adequate symptom relief from first-line drug therapy. Symptomatic obstructive hypertrophic cardiomyopathy is a type of hypertrophic cardiomyopathy where the heart muscle is restricted. 

Cardiac myosin inhibitors are the first US Food and Drug Administration (FDA)-approved class of medication to specifically target the thickening of the heart muscle instead of treating the symptoms; however, they are monitored under the FDA’s Risk Evaluation and Mitigation Strategies program, which may create additional steps and time for both the clinician and the patient. Clinicians require special training to prescribe the medication, and patients require regular screenings.

“These new drugs offer an alternative for patients who have failed first-line therapy and either want to delay or possibly avoid more aggressive options,” Ommen says in a release. “With this guideline, we’re providing clinicians with point-of-care guidance about effectively using this first-in-class, evidence-based treatment option and improving their patients’ quality of life.”

Evolving Recommendations for Exercise 

In addition to medication treatment, growing evidence is showing that the benefits of exercise outweigh the potential risks for patients with hypertrophic cardiomyopathy. Low-to-moderate intensity recreational exercise should be part of how hypertrophic cardiomyopathy patients manage their overall health. For some HCM patients, competitive sports may be considered in consultation with hypertrophic cardiomyopathy clinical specialists.

“Recommendations for physical activity continue to evolve with research,” Ommen says in a release. “As part of a healthy lifestyle, patients with hypertrophic cardiomyopathy are now encouraged to engage in low-to-moderate intensity physical activities. We’re seeing how vigorous physical activities can be reasonable for some individuals. With shared decision-making between the clinician and the patient, some patients may even be able to return to competitive sports.”

Emphasizing Risk Assessment for Sudden Cardiac Death

Poorly managed hypertrophic cardiomyopathy may lead to many complications including sudden cardiac death. The new guideline includes recommendations for assessing and managing the risk of sudden cardiac death by establishing clear risk markers. Guidance for integrating risk markers with tools to estimate an individual patient’s sudden cardiac death risk score is recommended to aid in the patient/clinician shared decision-making regarding implantable cardioverter defibrillator placement, incorporating a patient’s personal level of risk tolerance and specific treatment goals including quality of life.

Several recommendations in the new guideline extend to pediatric patients. A specific pediatric risk stratification for sudden cardiac death is emphasized, with risk calculators specific to children and adolescents and stressing the importance of hypertrophic cardiomyopathy centers with expertise in pediatrics. The new guideline extends exercise stress testing recommendations to include children diagnosed with hypertrophic cardiomyopathy to help determine functional capacity and provide prognostic feedback.

Comprehensive Collaboration

The 2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy is published simultaneously today in the Journal of the American College of Cardiology and Circulation.

In addition to the American College of Cardiology and the American Heart Association, the guideline was written in collaboration with and endorsed by the American Medical Society for Sports Medicine, the Heart Rhythm Society, the Pediatric & Congenital Electrophysiology Society, and the Society for Cardiovascular Magnetic Resonance.

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