Hypertrophic cardiomyopathy screening

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [mailto:mgibson@perfuse.org];

Overview
Genetic testing is the diagnostic study of choice to definitively diagnose hypertrophic cardiomyopathy. While definitive, these techniques can be expensive and can be difficult to access. If the mutation has already been identified in other family members, it is fairly efficient to test for that isolated mutation.

Screening Methods if Genetic Testing is Not Available
Absent the availability of genetic testing, clinical screening should be conducted using the history, physical exam, the electrocardiogram and the echocardiogram in adolescent patients aged 12 to 18 who are first degree relatives of patients with a confirmed diagnosis of hypertrophic cardiomyopathy. Because HCM can have a delayed age of onset, individuals over the age of 18 with an affected first degree relative should have screening every 5 years. Unless the child is engaged in extremely competitive sports or has an aggressive family history of HCM with premature death, screening is generally not recommended in children under the age of 12.

Screening of Competitive Athletes for Hypertrophic Cardiomyopathy
Screening for hypertrophic cardiomyopathy(HCM) is a controversial subject in the medical community, as HCM is the leading cause of sudden death in athletes.

Family History
The AHA/ACC guidelines recommend that a family history should be obtined in athletes to ascertain if there is a history of sudden death or if HCM is present in any family members.

Physical Examination
If the family history is positive, then a physical examination and echocardiography should be performed.

Yield of Aggressive Testing: The Italian Experience

 * In Italy, all competitive athletes are required to undergo pre-participation screening for the presence of HCM.


 * This screening consists of:
 * A 12-lead ECG
 * A general and cardiovascular physical examination, including blood pressure measurements
 * A family history


 * Over 3 million competitive athletes are evaluated each year, and athletes judged to be free of cardiovascular disease receive a certificate enabling them to participate in competitive athletics.


 * In a study done in Italy over a 9-year period (1990-1998), 41 of the 4450 athletes screened on echocardiography showed LV hypertrophy, with an increased wall thicknesses. Only four athletes demonstrated a maximal LV wall thickness of 13 mm or more.  Thus, the yield of echocardiographic screening appears to be low.

Follow-Up of Patients with diagnosed HOCM
These patients are re-evaluated every 12 to 18 months.

2011 ACCF/AHA Guideline Recommendations: Genetic Testing Strategies/Family Screening
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Class I
1. Evaluation of familial inheritance and genetic counseling is recommended as part of the assessment of patients with HOCM. (Level of Evidence: B)

2. Patients who undergo genetic testing should also undergo counseling by someone knowledgeable in the genetics of cardiovascular disease so that results and their clinical significance can be appropriately reviewed with the patient. (Level of Evidence: B)

3. Screening (clinical, with or without genetic testing) is recommended in first-degree relatives of patients with HOCM. (Level of Evidence: B)

4. Genetic testing for HOCM and other genetic causes of unexplained cardiac hypertrophy is recommended in patients with an atypical clinical presentation of HOCM or when another genetic condition is suspected to be the cause. (Level of Evidence: B)

Class IIa
1. Genetic testing is reasonable in the index patient to facilitate the identification of first-degree family members at risk for developing HOCM. (Level of Evidence: B)

Class IIb
1. The usefulness of genetic testing in the assessment of risk of sudden cardiac death in HOCM is uncertain. (Level of Evidence: B)

Class III (No Benefit)
1. Genetic testing is not indicated in relatives when the index patient does not have a definitive pathogenic mutation. (Level of Evidence: B)

2. Ongoing clinical screening is not indicated in genotype-negative relatives in families with HOCM. (Level of Evidence: B)}}

Guideline Resources
2011 ACCF/AHA Guideline for the Diagnosis and Treatment of Hypertrophic Cardiomyopathy