Risk stratification for HCM:
HCM is one of the most common causes of sudden death in young people (≤1% annually and predominantly in patients <25 years), including competitive athletes.
Sudden death is paradoxically low in patients >60 years of age.
It is caused by fast VT or VF due to reentry in the electrophysiological substrate of scarring and disarray.
There is no evidence that bradyarrhythmias play a role.
High risk factors are:
◆ Previous cardiac arrest (although most are lethal)
◆ Massive LV hypertrophy (≥30 mm)
◆ Family history of HOCM-related sudden cardiac death
◆ Non-sustained VT on Holter or during exercise.
◆ Unexplained syncope.
