title: Clinical characteristics and natural history of hypertrophic cardiomyopathy with midventricular obstruction.
abstract: BACKGROUND
  The prevalence, clinical characteristics and natural history of patients with hypertrophic cardiomyopathy (HCM) and midventricular obstruction (MVO) have not been adequately studied.
  
  
  RESULTS
  A single-center cohort consisting of 423 patients (mean age, 49.3±17.2 years; 66.2% male) was thoroughly followed up for a median of 84 months (7 years; range, 6-480 months). MVO, characterized by the echocardiographic appearance of midventricular muscular apposition with a simultaneous mid-cavitary gradient ≥30mmHg, was identified in 34 patients (8%). Patients with MVO tended to be more symptomatic during their initial evaluation (>90% presented with NYHA class ≥II) compared to the rest of the HCM cohort. Apical aneurysm formation was identified in more than one-fourth of patients with MVO (26.5%), being a characteristic of the group. On multivariate Cox regression hazard analysis, presence of MVO strongly predicted progression to end-stage (burnt out) HCM and related heart failure (HF) deaths (hazard ratio, [HR], 2.62; 95% confidence interval [CI]: 1.2-8.8; P=0.047), as well as sudden death and associated lethal arrhythmic events (HR, 3.3; 95% CI: 1.26-8.85; P=0.016).
  
  
  CONCLUSIONS
  MVO is a distinct phenotype of HCM associated with unfavorable prognosis in terms of end-stage HCM, sudden death and lethal arrhythmic events. The high adverse outcome rate necessitates early recognition of MVO and appropriate therapeutic interventions.
authors.affiliation: Cardiomyopathies Center, First Cardiology Department, AHEPA University Hospital.
authors.forename: Georgios K
authors.initials: GK
authors.lastname: Efthimiadis
authors.forename: Efstathios D
authors.initials: ED
authors.lastname: Pagourelias
authors.forename: Despoina
authors.initials: D
authors.lastname: Parcharidou
authors.forename: Thomas
authors.initials: T
authors.lastname: Gossios
authors.forename: Vasileios
authors.initials: V
authors.lastname: Kamperidis
authors.forename: Efstratios K
authors.initials: EK
authors.lastname: Theofilogiannakos
authors.forename: Zoi
authors.initials: Z
authors.lastname: Pappa
authors.forename: Soultana
authors.initials: S
authors.lastname: Meditskou
authors.forename: Stavros
authors.initials: S
authors.lastname: Hadjimiltiades
authors.forename: Christodoulos
authors.initials: C
authors.lastname: Pliakos
authors.forename: Haralampos
authors.initials: H
authors.lastname: Karvounis
authors.forename: Ioannis H
authors.initials: IH
authors.lastname: Styliadis
mesh_terms: D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000000981:diagnostic imaging / Q000209:etiology / Q000401:mortality / Q000503:physiopathology; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology; D003645:Death, Sudden / Q000209:etiology / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D014463:Ultrasonography; D014694:Ventricular Outflow Obstruction / Q000150:complications / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology