Clinical Profile of Thromboembolic Events in Patients With Hypertrophic Cardiomyopathy in a Regional Japanese Cohort ― Results From Kochi RYOMA Study ―

BACKGROUND: There is limited information about the clinical profiles of patients with hypertrophic cardiomyopathy (HCM) and thromboembolic events in a community-based Japanese patient cohort.Methods and Results:In 2004, we established a cardiomyopathy registration network in Kochi Prefecture that comprised 9 hospitals, and finally 293 patients with HCM were followed. The mean age at registration was 63±14 years, and 197 patients (67%) were men. At registration, 86 patients (29%) had documented atrial fibrillation (AF). During a mean follow-up period of 6.1±3.2 years, thromboembolic events, including 3 embolic stroke deaths, occurred in 23 patients. The 5-year embolic event rate was 5.5%. During the follow-up period, an additional 31 patients (11%) had documentation of AF and finally a total of 117 patients (40%) developed AF. The 5-year embolic event rate in those 117 patients with AF was 12.3%. Of the 23 patients with embolic events, 12 had AF prior to the embolic complications and another 6 had documented AF after thromboembolism. AF was not detected in the remaining 5 patients. The CHADS2score did not correlate with the embolic outcome in HCM patients. CONCLUSIONS: In this community-based registry, thromboembolic events were not rare in patients with HCM. All patients with HCM in whom AF develops should be given anticoagulation therapy regardless of their CHADS2score.