TABLE 3

Risk-stratification models for primary prevention of sudden cardiac death in hypertrophic cardiomyopathy

North American modelEuropean model
An implantable cardioverter-defibrillator (ICD) is reasonable (class IIa recommendation, level of evidence C—limited evidence) if any of the following are present:

  • Family history of sudden death

  • Unexplained syncope

  • Maximum left ventricular wall thickness ≥ 30 mm


Or if the patient has any other risk factor or modifier for sudden cardiac death and either of the following:

  • Nonsustained ventricular tachycardia

  • Abnormal blood pressure response during exercise (decrease or failure to increase systolic blood pressure ≥ 20 mm Hg during exercise stress test)

The following factors are used to electronically calculate the 5-year risk of sudden cardiac death:

  • Family history of sudden death

  • Unexplained syncope

  • Maximum left ventricular wall thickness

  • Nonsustained ventricular tachycardia

  • Age

  • Left atrial diameter

  • Left ventricular outflow gradient


5-year risk < 4%: an ICD is generally not indicated
5-year risk ≥ 4% to < 6%: an ICD may be considered
5-year risk ≥ 6%: an ICD should be considered

  • Based on information in references 9 and 30.