title: Assessment and significance of left ventricular mass by cardiovascular magnetic resonance in hypertrophic cardiomyopathy.
abstract: OBJECTIVE
  Our aim was to assess the distribution and clinical significance of left ventricular (LV) mass in patients with hypertrophic cardiomyopathy (HCM).
  
  
  BACKGROUND
  Hypertrophic cardiomyopathy is defined echocardiographically by unexplained left ventricular wall thickening. Left ventricular mass, quantifiable by modern cardiovascular magnetic resonance techniques, has not been systematically assessed in this disease.
  
  
  METHODS
  In 264 HCM patients (age 43 +/- 18 years; 75% men), LV mass by cardiovascular magnetic resonance was measured, indexed by body surface area, and compared with that in 606 healthy control subjects.
  
  
  RESULTS
  The LV mass index in HCM patients significantly exceeded that of control subjects (104 +/- 40 g/m(2) vs. 61 +/- 10 g/m(2) in men and 89 +/- 33 g/m(2) vs. 47 +/- 7 g/m(2) in women; both p < 0.0001). However, values were within the normal range (< or = mean +2 SDs for control subjects) in 56 patients (21%), and only mildly increased (mean +2 to 3 SDs) in 18 (16%). The LV mass index showed a modest relationship to maximal LV thickness (r(2) = 0.38; p < 0.001), and was greater in men (104 +/- 40 g/m(2) vs. 89 +/- 33 g/m(2) in women; p < 0.001) and in patients with resting outflow obstruction (121 +/- 43 g/m(2) vs. 96 +/- 37 g/m(2) in nonobstructives; p < 0.001). During a 2.6 +/- 0.7-year follow-up, markedly increased LV mass index proved more sensitive in predicting outcome (100%, with 39% specificity), whereas maximal wall thickness >30 mm was more specific (90%, with 41% sensitivity).
  
  
  CONCLUSIONS
  In distinction to prior perceptions, LV mass index was normal in about 20% of patients with definite HCM phenotype. Therefore, increased LV mass is not a requirement for establishing the clinical diagnosis of HCM. The LV mass correlated weakly with maximal wall thickness, and proved more sensitive in predicting outcome.
authors.affiliation: Regional Referral Center for Myocardial Diseases and Radiology Unit, Azienda Ospedaliera Universitaria Careggi, Florence, Italy. olivottoi@ao-careggi.toscana.it
authors.forename: Iacopo
authors.initials: I
authors.lastname: Olivotto
authors.forename: Martin S
authors.initials: MS
authors.lastname: Maron
authors.forename: Camillo
authors.initials: C
authors.lastname: Autore
authors.forename: John R
authors.initials: JR
authors.lastname: Lesser
authors.forename: Luigi
authors.initials: L
authors.lastname: Rega
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Casolo
authors.forename: Marcello
authors.initials: M
authors.lastname: De Santis
authors.forename: Giovanni
authors.initials: G
authors.lastname: Quarta
authors.forename: Stefano
authors.initials: S
authors.lastname: Nistri
authors.forename: Franco
authors.initials: F
authors.lastname: Cecchi
authors.forename: Carol J
authors.initials: CJ
authors.lastname: Salton
authors.forename: James E
authors.initials: JE
authors.lastname: Udelson
authors.forename: Warren J
authors.initials: WJ
authors.lastname: Manning
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Maron
mesh_terms: D000328:Adult; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D010641:Phenotype; D018570:Risk Assessment; D013318:Stroke Volume; D014463:Ultrasonography