Stroke and Embolic Events in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is one of the most common genetic cardiac disorders, with markedly heterogeneous clinical manifestations and natural history. Although stroke and systemic embolic events are known to occur as complications of HCM, few data are available on the occurrence and profile of these events in this patient population. In a previous study, stroke and systemic embolic events showed an incidence of 0.8% per year, and these ominous and profound complications were more common in patients with atrial fibrillation (AF). Anticoagulation has proved effective in reducing the incidence of these events in patients with HCM and AF. Also, current guidelines state that anticoagulation is indicated in patients with HCM with paroxysmal, persistent, or chronic AF, regardless of known embolic risk factors such as those covered by the congestive heart failure, hypertension, age=75 years, diabetes mellitus, stroke score. Given the often paroxysmal and asymptomatic nature of AF, however, its diagnosis is sometimes difficult in real-world clinical practice. It is therefore possible that a subclinical, asymptomatic (silent) paroxysmal episode or a first paroxysmal episode of AF in patients without previously documented AF may lead to stroke and peripheral embolization. The epidemiology of these events in patients without documented AF is an important clinical issue. This is especially true for patients at high risk of embolization, such as those with HCM, although the connection remains unclear. The aim of this study was to investigate the frequency and clinical features of patients with HCM with stroke and systemic embolic events in a tertiary referral cohort in Japan and to clarify the epidemiology and risk factors of these events in patients with HCM without previously documented AF.