Background:End-stage hypertrophic cardiomyopathy (HCM) is complicated by substantial adverse events.However,few studies have focused on electrocardiographic features and their prognostic values in HCM.This study aimed to evaluate the clinical manifestations and prognostic value of electrocardiography in patients with end-stage HCM.Methods:End-stage HCM patients were enrolled from a total of 1844 consecutive HCM patients from April 2002 to November 2013 at Fuwai Hospital.Clinical data,including medical history,electrocardiography,and echocardiography,were analyzed.Cox hazards regression analysis was used to assess the risk factors for cardiovascular mortality.Results:End-stage HCM was identified in 99 (5.4％) patients,averaged at 52 ± 16 years old at entry.Atrial fibrillation was observed in 53 patients and mural thrombus in 19 patients.During 3.9 ± 3.0 years of follow-up,embolic stroke,refractory heart failure,and death or transplantation were observed in 20,39,and 51 patients,respectively.The incidence of annual mortality was 13.2％.Multivariate Cox hazards regression analysis identified New York Heart Association Class (NYHA) Ⅲ/Ⅳ at entry (hazard ratio [HR]:1.99;95％ confidence interval [CI]:1.05-3.80;P =0.036),left bundle branch block (LBBB) (HR:2.80;95％ CI:1.47-5.31;P =0.002),and an abnormal Q wave (HR:2.21;95％ CI:1.16-4.23;P =0.016) as independent predictors of cardiovascular death,in accordance with all-cause death and heart failure-related death.Conclusions:LBBB and an abnormal Q wave are risk factors of cardiovascular mortality in end-stage HCM and provide new evidence for early intervention.Susceptibility of end-stage HCM patients to mural thrombus and embolic events warrants further attention.