title: Apparent left ventricular cavity dilatation during PET/CT in hypertrophic cardiomyopathy: Clinical predictors and potential mechanisms.
abstract: Apparent left ventricular cavity dilatation (LVCD) in patients with hypertrophic cardiomyopathy (HCM) is an incompletely understood phenomenon. We aimed at investigating its clinical predictors and potential mechanisms.
  
  
  
  Sixty one HCM patients underwent N-13-ammonia PET for visual evaluation of LVCD, transient ischemic dilatation (TID) index, myocardial blood flow (MBF), coronary flow reserve (CFR), and regional myocardial perfusion (rMP). TID index was also derived at 2-4 and 15-20 minutes.
  
  
  
  Visual LVCD and quantitative TID (>1.13 abnormal) agreement were excellent (k 0.91; P < .0001). LVCD-positive (n = 32) patients had greater LV thickness (2.26 ± 0.59 vs 1.92 ± 0.41 cm; P = .005), but lower stress MBF (1.66 ± 0.42 vs 2.07 ± 0.46 mL/minute/g; P < .0001), and CFR (1.90 ± 0.46 vs 2.46 ± 0.69; P < .0001) than LVCD-negative (n = 29) patients. Abnormal rMP was present in 31/32 LVCD-positive but only 12/29 (P < .0001) LVCD-negative. TID index was higher at 2-4 (1.30 ± 0.13) than at 15-20 minutes (1.27 ± 0.12; P = .001) in LVCD-positive, whereas it was the same (1.04 ± 0.07 vs 1.04 ± 0.07; P = .9) in LVCD-negative. In multivariate analysis, global peak MBF, abnormal rMP, and LV thickness were the best predictors of LVCD.
  
  
  
  Apparent LVCD is a common finding in HCM, intimately related to abnormal myocardial perfusion, globally impaired vasodilator flow reserve, and degree of hypertrophy. In addition to regional and/or diffuse subendocardial ischemia, some degree of true LV chamber dilatation may also contribute to the occurrence of apparent LVCD in HCM.
authors.affiliation: Department of Radiology, Johns Hopkins University, Baltimore, MD, USA. pbravo@uw.edu.|Division of Cardiology, University of Washington, 1959 NE Pacific St., HSB AA522, Seattle, WA, 98133, USA. pbravo@uw.edu.
authors.forename: Paco E
authors.initials: PE
authors.lastname: Bravo
authors.affiliation: Department of Radiology, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Abdel
authors.initials: A
authors.lastname: Tahari
authors.affiliation: Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Iraklis
authors.initials: I
authors.lastname: Pozios
authors.affiliation: Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Hong-Chang
authors.initials: HC
authors.lastname: Luo
authors.affiliation: Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany.
authors.forename: Frank M
authors.initials: FM
authors.lastname: Bengel
authors.affiliation: Department of Radiology, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Wahl
authors.affiliation: Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: M Roselle
authors.initials: MR
authors.lastname: Abraham
authors.affiliation: Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Theodore P
authors.initials: TP
authors.lastname: Abraham
mesh_terms: D015142:Baltimore / Q000453:epidemiology; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D015897:Comorbidity; D005260:Female; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000706:statistics & numerical data*; D000072078:Positron Emission Tomography Computed Tomography / Q000706:statistics & numerical data*; D011379:Prognosis; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity
keywords: HCM; PET; TID; apparent LV cavity dilatation; myocardial ischemia