Background Severe left ventricular (LV) systolic dysfunction is an uncommon complication of hypertrophic cardiomyopathy (HCM) that is associated with poor prognosis. Small observational series suggest that patients with rare causes of HCM are more likely to develop systolic impairment than those with idiopathic disease or mutations in cardiac sarcomeric protein genes. The aim of this study was to test this hypothesis by comparing the prevalence of systolic dysfunction and its impact on prognosis in patients with different causes of HCM.
Methods and results 1697 patients (52 (40–63) years, 1160 (68%) males) with HCM followed at two European referral centres were studied. Diagnosis of specific aetiologies was made on the basis of clinical examination, cardiac imaging and targeted genetic and biochemical testing. The primary survival outcome was all-cause mortality or heart transplantation (HTx) for end-stage heart failure (HF). Secondary outcomes were HF-related death, sudden cardiac death, stroke-related death and non-cardiovascular death. Systolic dysfunction (LV ejection fraction <50% by two-dimensional (2D) echocardiography) at first evaluation was more frequent in rare phenocopies than in idiopathic or sarcomeric HCM (105/409 (26%) vs 40/1288 (3%), respectively (p<0.0001)). All-cause death/HTx and HF-related death were more frequent in rare phenocopies compared with idiopathic or sarcomeric HCM (p<0.0001). All-cause mortality and HF-related death were highest in patients with cardiac amyloidosis (p<0.0001).
Conclusions In adults with HCM, LV systolic dysfunction is more frequent in those with rare phenocopies. When combined with age at presentation, it is a marker for specific aetiologies and is associated with poorer long-term survival.
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Contributors SR, CR and PME conceived and designed the research. SR, NR, LRL, CCQ and OG acquired the data. SR, EB and HB analysed and interpreted the data. SR, HB and COM performed statistical analysis. SR drafted the manuscript. EB, COM, HB, PR, CCQ, MTE, AP, WMcK, CR and PME made critical revision of the manuscript for important intellectual content. All authors have given final approval of the version published and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Funding SR has been supported by Borse di Studio per la ricerca scientifica ‘SIC-SANOFI’. Part of this work was funded by the National Institute for Health Research University College London Hospitals Biomedical Research Centre.
Competing interests None declared.
Ethics approval The National Research Ethics Service (NRES)/Ethics Committee London Harrow approval for data collection at The Heart Hospital was obtained that included waiving patient's consent given the retrospective observational nature of the work. Patients at the Department of Cardiology at the Bologna University have been approved by the appropriate local ethics committee.
Provenance and peer review Not commissioned; externally peer reviewed.