title: Mechanisms of exercise intolerance in patients with hypertrophic cardiomyopathy.
abstract: OBJECTIVE
  To determine the relation between echocardiogram findings and exercise capacity in hypertrophic cardiomyopathy (HCM).
  
  
  RESULTS
  Sixty-three patients (48 +/- 15 years) were referred for cardiopulmonary testing and exercise echocardiography. They were classified by morphology: proximal (n = 11), reverse curvature (n = 32), apical (n = 7), and concentric HCM (n = 13). There were more women in proximal and reverse curvature groups. Proximal HCM patients were older. Maximal left ventricular thickness was highest in reverse curvature group. At peak exercise, concentric HCM achieved the lowest percent predicted maximal Vo2. Excluding apical group, no significant differences in gradient were noted between groups. Overall, no statistically significant correlation was found between peak Vo2, wall thickness, and gradient. Significant correlations were noted between peak Vo2 and indexed left atrial (LA) volume (r = -0.52), lateral E' (r = 0.50), and lateral E/E' ratio (r = -0.46). A multivariate model including age, lateral E', indexed LA volume, and mitral A wave explained 46% of the variance in peak Vo2 (P = .01).
  
  
  CONCLUSIONS
  Lateral E' and indexed LA volume are negatively correlated with functional capacity. Although patients with concentric morphology achieved the lowest peak Vo2, wall thickness and gradient did not predict exercise capacity.
authors.affiliation: Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA. vyvanle@gmail.com
authors.forename: Vy-Van
authors.initials: VV
authors.lastname: Le
authors.forename: Marco V
authors.initials: MV
authors.lastname: Perez
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Wheeler
authors.forename: Jonathan
authors.initials: J
authors.lastname: Myers
authors.forename: Ingela
authors.initials: I
authors.lastname: Schnittger
authors.forename: Euan A
authors.initials: EA
authors.lastname: Ashley
mesh_terms: D000328:Adult; D000368:Aged; D001944:Breath Tests; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging / Q000503:physiopathology*; D025401:Echocardiography, Stress; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged