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What is Hypertrophic Cardiomyopathy (HCM)?

NYU Winthrop Hospital’s HCM Center is dedicated to helping patients and families coordinate the best care available, and strives to forge a committed, caring, lifelong relationship with each patient.

Hypertrophic cardiomyopathy (HCM) is an inherited disease that can appear without warning or without obvious family history. HCM affects 1 in 500 individuals across all age groups, both genders and every race. In general, one half of all offspring of a known HCM patient will inherit the gene, although when and how the disease manifests itself is highly variable.

HCM is characterized by myocardial disarray, which creates abnormalities in the heart muscle fibers and makes accurate diagnosis and treatment important. HCM often involves:

  • excessive thickening of the inter-ventricular septum or other areas
  • increased left ventricular stiffness (diastolic function abnormality)
  • left ventricular outflow tract (LVOT) obstruction
  • mitral valve regurgitation
  • pulmonary hypertension
  • heart failure (with or without congestion)
  • risk of sudden cardiac death (ventricular tachycardia)

HCM Involves a Diverse Range of Symptoms

The clinical presentation of HCM is diverse, ranging from individuals with no apparent symptoms to those with:

  • disabling symptoms of heart failure
  • exercise intolerance and fatigue
  • shortness of breath (dyspnea)
  • chest pain
  • palpitations
  • lightheadedness or passing out (syncope)

HCM is the most common cause of sudden cardiac death in individuals under 30 who appear otherwise healthy. A conclusive diagnosis, which may include genetic testing, is vital to the prognosis and determination of treatment options.

While diagnosis traditionally involves an echocardiogram, the subtleties of the disease manifestations may be difficult to discern, requiring comprehensive focused echocardiographic evaluations using multiple views. When echocardiogram is inconclusive or suspicious for severe thickening or apical variant, cardiac MRI may be required. Other diagnostic testing may include periodic Holter monitoring, stress testing, and cardiac catheterization.

HCM Management

Although there is no cure, most patients with symptoms can be managed with:

  • appropriate education and lifestyle modification
  • medical and pharmacologic therapy, including beta-blockers, calcium antagonists, anti-arrhythmic drugs and anticoagulants
  • pacemaker therapy
  • implantation of an internal cardioverter defibrillator (ICD) to prevent sudden cardiac death

When symptoms persist despite the above measures, surgical myectomy or catheter-based alcohol septal ablation (ASA) may be used to:

  • reduce the size of the thickened septum
  • enlarge the ventricular outflow tract
  • eliminate obstruction and mitral regurgitation
  • improve diastolic function
  • improve pulmonary hypertension
  • improve heart failure symptoms

HCM is an inherited disease, and it is not enough to simply treat the patient. All blood relatives must be evaluated by genetic testing or echocardiogram— the latter at routine intervals regardless of initial results — and all children need to be evaluated by pediatric cardiologists specializing in the disease.