The Arrhythmic Risk

The clinical course of the disease is usually benign and many patients are asymptomatic, or have mild symptoms. A minority of patients are at risk for arrhythmias, some of which can also be life-threatening. Therefore, research over the last 20-30 years has focused on identifying the minority of patients with high arrhythmic risk who may benefit from the implantation of an automatic defibrillator (ICD).

The main arrhythmic risk factors are:

• Previous cardiac arrest, or prolonged ventricular arrhythmia which resulted in cardiac collapse
• Syncope (fainting with loss of consciousness) from an unknown cause (e.g., fainting due to blood sampling or sudden changes in position should not be considered as a risk factor)
• Presence in the family of one or more cases of people who died suddenly when they were young
• Important increase in cardiac wall thickness (hypertrophy)
• Repetitive ventricular arrhythmias (ventricular tachycardia) detected by 24-hour Holter ECG monitoring

The doctor's judgment is important in assessing risk factors, their severity and combination, and the risk stratification is individual for each patient. It is therefore essential that the risk stratification is carried out in Centres expert in this disease.

Arrhythmic risk may vary over time, so it is advisable that patients with hypertrophic cardiomyopathy are followed up with regular visits (usually every 6-12 months).