Clinical course of patients with hypertrophic cardiomyopathy away from tertiary referral care

AIMS: Data on the clinical course of hypertrophic cardiomyopathy (HCM) are mainly derived from tertiary HCM centre studies, and knowledge of clinical outcomes of patients leaving specialty care and returning to local physicians is limited due to gaps between clinical encounters or complete loss of follow‐up. This survey aims to describe the clinical course of HCM in patients following their evaluation at a tertiary referral centre. METHODS AND RESULTS: A comprehensive outcomes survey was developed and sent to 4495 eligible patients with HCM previously evaluated at Mayo Clinic. Questions assessed general well‐being, New York Heart Association class, procedures performed, and probable HCM‐triggered ventricular arrhythmic events (VAEs) since last visit. In total, 2058 patients (mean age 63 ± 15 years; 42% female) responded to the survey covering a total of 10 510 patient‐years with an average of 5.4 ± 6.4 years of follow‐up since their last on‐campus/virtual visit to Mayo Clinic. During their time away from specialty care, 20% of patients reported having cardiac‐related hospitalizations and 25% reported having cardiac‐related procedures. Similar to high‐risk referral cohorts, 5% of patients reported VAEs with an event rate of 0.98 events/100 patient‐years. The prevalence of atrial fibrillation, syncope, pre‐syncope, cardiac‐related hospitalizations, and VAEs during time away from specialty care increased significantly with increasing New York Heart Association class (P < 0.001). CONCLUSIONS: Acknowledging ascertainment bias, the clinical course of patients away from tertiary care may be more severe than previously anticipated. Among those with exertional symptoms, HCM‐related morbidity increased substantially. Higher risk HCM patients should remain in contact with HCM specialty care.