Apparent left ventricular cavity dilatation during PET/CT in hypertrophic cardiomyopathy: Clinical predictors and potential mechanisms

Paco E. Bravo, Abdel Tahari, Iraklis Pozios, Hong Chang Luo, Frank M. Bengel, Richard L. Wahl, M. Roselle Abraham, Theodore P. Abraham

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Background: 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. Methods: 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. Results: 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. Conclusion: 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.

Original languageEnglish
Pages (from-to)1304-1314
Number of pages11
JournalJournal of Nuclear Cardiology
Volume23
Issue number6
DOIs
StatePublished - Dec 1 2016

Keywords

  • HCM
  • PET
  • TID
  • apparent LV cavity dilatation
  • myocardial ischemia

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