Arrhythmia monitoring in HCM patients is used not only for determining risk of sudden death and potential need for an implantable defibrillator, but also for detecting atrial fibrillation (AFib) and implementing anti-coagulation for stroke prevention.
If you are looking for a good survey of current practices in the treatment of HCM, a recent article published in the journal Structural Heart by Dr. Ahmad Masri and the team at Oregon Health and Sciences University (OHSU) provides an informative overview of thirty controversies and considerations in the treatment of HCM. This article explains in some detail how the doctors at this HCM Center approach these situations.
As reported in this New York Times article, radiation has been used as a successful treatment in five patients with ventricular arrhythmias who had previously failed standard treatment using catheter radiofrequency ablation. The complete study was published last week in the New England Journal of Medicine.
Because long term effects of radiation to the heart are unknown, this method is still quite experimental and could potentially cause long term side effects such as lung and heart damage. Science Daily reported that the researchers have performed the procedure on 23 patients to date, and are currently enrolling patients in a clinical trial.