title: Myocardial contrast echocardiography for the distinction of hypertrophic cardiomyopathy from athlete's heart and hypertensive heart disease.
abstract: BACKGROUND
  Myocardial contrast echocardiography (MCE) is able to measure in vivo relative blood volume (rBV, i.e., capillary density), and its exchange frequency b, the constituents of myo-cardial blood flow (MBF, ml min-1 g-1). This study aimed to assess, by MCE, whether left ventricular hypertrophy (LVH) in hypertrophic cardiomyopathy (HCM) can be differentiated from LVH in triathletes (athlete's heart, AH) or from hypertensive heart disease patients (HHD).
  
  
  METHODS
  Sixty individuals, matched for age (33 +/- 10 years) and gender, and subdivided into four groups (n = 15) were examined: HCM, AH, HHD and a group of sedentary individuals without LVH (S). rBV (ml ml-1), b (min-1) and MBF, at rest and during adenosine-induced hyperaemia, were derived by MCE in mid septal, lateral and inferior regions. The ratio of MBF during hyperaemia and MBF at rest yielded myocardial blood flow reserve (MBFR).
  
  
  RESULTS
  Septal wall rBV at rest was lower in HCM (0.084 +/- 0.023 ml ml-1) than in AH (0.151 +/- 0.024 ml ml-1, p <0.01) and in S (0.129 +/- 0.026 ml ml-1, p <0.01), but was similar to HHD (0.097 +/- 0.016 ml ml-1). Conversely, MBFR was lowest in HCM (1.67 +/- 0.93), followed by HHD (2.8 +/- 0.93, p <0.01), by S (3.36 +/- 1.03, p <0.001) and by AH (4.74 +/- 1.46, p <0.0001). At rest, rBV <0.11 ml ml-1 accurately distinguished between HCM and AH (sensitivity 99%, specificity 99%), similarly MBFR < or =1.8 helped to distinguish between HCM and HHD (sensitivity 100%, specificity 77%).
  
  
  CONCLUSIONS
  rBV at rest, most accurately distinguishes between pathological LVH due to HCM and physiological, endurance-exercise induced LVH.
authors.affiliation: Department of Cardiology, University Hospital, Bern, Switzerland. andreas.indermuehle@kcl.ac.uk
authors.forename: Andreas
authors.initials: A
authors.lastname: Indermühle
authors.forename: Rolf
authors.initials: R
authors.lastname: Vogel
authors.forename: Tobias
authors.initials: T
authors.lastname: Rutz
authors.forename: Pascal
authors.initials: P
authors.lastname: Meier
authors.forename: Christian
authors.initials: C
authors.lastname: Seiler
mesh_terms: D000328:Adult; D056352:Athletes; D001783:Blood Flow Velocity / Q000502:physiology; D001810:Blood Volume / Q000502:physiology; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000000981:diagnostic imaging; D006973:Hypertension / Q000000981:diagnostic imaging* / Q000503:physiopathology; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008833:Microcirculation / Q000502:physiology; D012146:Rest; D014463:Ultrasonography