title: Tissue Doppler-derived indices predict exercise capacity in patients with apical hypertrophic cardiomyopathy.
abstract: BACKGROUND
  Although impaired left ventricular (LV) diastolic function is a prominent feature of hypertrophic cardiomyopathy (HCM), diastolic function and its relation to exercise capacity in apical HCM (ApHCM) has not been explored previously. This study was sought to determine the relationship between diastolic mitral annular velocities combined with conventional Doppler indexes and exercise capacity in patients with ApHCM.
  
  
  METHODS
  Twenty-nine patients with ApHCM (24 men; mean age +/- SD, 57 +/- 10 years) underwent supine bicycle exercise with simultaneous respiratory gas analysis and two-dimensional and Doppler echocardiographic study.
  
  
  RESULTS
  The mitral inflow velocities (early filling [E], late filling, and deceleration time) were traced and measured. Early diastolic mitral annular velocity (E') was measured at the septal corner of mitral annulus by Doppler tissue imaging (DTI) from the apical four-chamber view. Pro-brain natriuretic peptide (proBNP) was measured at the time of echocardiography using a quantitative electrochemiluminescence immunoassay. E/E' ratio correlated inversely with maximal oxygen uptake (Vo(2)max) [r = - 0.47, p = 0.0106]. There was a significant positive correlation between E' and Vo(2)max (r = 0.41, p = 0.024). However, no correlation was found between conventional two-dimensional, Doppler indices, and proBNP and Vo(2)max). Of all the echocardiographic and clinical parameters assessed, E/E' ratio had the best correlation with exercise capacity (r - 0.47) and was the strongest independent predictor of Vo(2)max by multivariate analysis (p = 0.0106).
  
  
  CONCLUSIONS
  DTI-derived indexes (E', E/E' ratio), an estimate of myocardial relaxation and LV filling pressures, correlate with exercise capacity in patients with ApHCM, suggesting that abnormal diastolic function may be a factor limiting exercise capacity.
authors.affiliation: Cardiology Division, Yonsei University College of Medicine, Seoul, Korea. jwha@yumc.yonsei.ac.kr
authors.forename: Jong-Won
authors.initials: JW
authors.lastname: Ha
authors.forename: Jung-Rae
authors.initials: JR
authors.lastname: Cho
authors.forename: Jin-Mi
authors.initials: JM
authors.lastname: Kim
authors.forename: Jeong-Ah
authors.initials: JA
authors.lastname: Ahn
authors.forename: Eui-Young
authors.initials: EY
authors.lastname: Choi
authors.forename: Seok-Min
authors.initials: SM
authors.lastname: Kang
authors.forename: Se-Joong
authors.initials: SJ
authors.lastname: Rim
authors.forename: Namsik
authors.initials: N
authors.lastname: Chung
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002312:Cardiomyopathy, Hypertrophic / Q000097:blood / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D005296:Ferrous Compounds; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020097:Natriuretic Peptide, Brain / Q000097:blood; D010101:Oxygen Consumption; D010446:Peptide Fragments / Q000097:blood; D018608:Ultrasonography, Doppler; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*
chemical_list: D005296:Ferrous Compounds; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; C020748:ferrous sulfate