HCM Risk-SCD

The HCM Risk-SCD estimates the risk of sudden cardiac death at 5 years in patients with hypertrophic cardiomyopathy.

The risk of SCD in 5 years for an individual HCM patient can be calculated from the following equation:

Probability of Sudden Cardiac Death at 5 years = 1 - 0.998^{exp(PrognosticIndex)}

where Prognostic Index = 0.15939858*Maximal wall thickness (mm) - 0.00294271*Maximal wall thickness2 (mm2) + 0.0259082*Left atrial diameter (mm) + 0.00446131*Maximal left ventricular outflow tract gradient (mmHg) + 0.4583082*Family history SCD + 0.82639195*NSVT + 0.71650361*Unexplained syncope - 0.01799934*Age at clinical evaluation (years).

It should not be used in:

• Paediatric patients (<16 years)
• Elite/competitive athletes
• HCM associated with metabolic diseases (e.g. Anderson-Fabry disease), and syndromes (e.g. Noonan syndrome).
• Patients with a previous history of aborted SCD or sustained ventricular arrhythmia who should be treated with an ICD for secondary prevention.

Caution should be exercised when assessing the SCD in patients following invasive reduction in left ventricular outflow tract obstruction with myectomy or alcohol septal ablation.

Acccording to ESC Guidelines, in patients with a 5-year risk of SCD <4%, an ICD is generally not indicated, in patients with a risk of 4 to less than 6%, an ICD may be considered and in patients with a 5-year risk ≥6%, an ICD should be considered.