Implantable Cardiac Monitors in Low Risk Hypertrophic Cardiomyopathy: To Protect and Serve, or Observe and Report?
HCM is associated with an increased risk of various cardiac arrhythmias, including atrial fibrillation (AF), nonsustained ventricular tachycardia (NSVT), and sustained ventricular tachycardia (VT). Furthermore, the presence of cardiac arrhythmias has an important effect on the prognosis of HCM patients, especially with respect to ventricular arrhythmias as a major cause of sudden cardiac death (SCD). In this issue of Journal of Cardiovascular Electrophysiology, Magnusson and Mörner describe the
... Mörner describe the incidence of NSVT, AF, and bradycardia in thirty patients at relatively low risk of SCD by utilizing an implantable cardiac monitor (ICM). These data are useful in demonstrating a fairly significant arrhythmia burden in a low risk population. The ramifications of these findings are a bit unclear, however. Certainly, atrial fibrillation is important to detect in order to mitigate the increased stroke risk by instituting anticoagulation. Detection of NSVT was less useful in this low risk population, but could be potentially more actionable in intermediate risk HCM patients. Thus, although further investigation is needed, the authors have taken the first step in determining appropriate treatment strategies for arrhythmias in HCM by helping to define the scope of the problem.