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Quantification of myocardial iron deposition by two-dimensional speckle tracking in patients with β-thalassaemia major and Blackfan–Diamond anaemia
  1. P Garceau,
  2. E T Nguyen,
  3. S Carasso,
  4. H Ross,
  5. J Pendergrast,
  6. G Moravsky,
  7. B Bruchal-Garbicz,
  8. H Rakowski
  1. Division of Cardiology, Department of Medicine, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
  1. Correspondence to Harry Rakowski, Toronto General Hospital, 4N-504, 585 University Avenue, Toronto, Ontario, M5G 2N2, Canada; harry.rakowski{at}uhn.on.ca

Abstract

Background Cardiac disease related to transfusional iron overload is the leading cause of death in patients with β-thalassaemia major. Early myocardial iron deposition predates decreased left ventricular dysfunction and currently is best assessed by cardiac magnetic resonance.

Methods Echocardiographic speckle tracking-derived myocardial mechanics were compared with cardiac MRI T2 star (T2*) calculations in 45 chronically transfused patients with β-thalassaemia major or Diamond–Blackfan anaemia (26 retrospectively and an additional 19 for validation). Two groups were studied: patients with presumed cardiac iron overload and interventricular T2* value ≤20 ms (low T2*) and patients with >20 ms (normal T2*). They were compared with a normal control group of 18 age- and gender-matched patients.

Results Patients with low T2* had a uniform decrease in longitudinal and circumferential strain compared with normal controls (−16±3% vs −20±3% and −20±4% vs −23±5%, respectively; p<0.0005). Peak twist and peak apical rotation were lower in patients with low T2* than in those with normal T2* or normal control patients. Conversely, no significant difference was observed between patients with normal T2* and controls. There was a strong and direct logarithmic correlation between average global longitudinal strain and T2* values (r=−0.68, p=0.0007). Using a cut-off of ≤−17%, global longitudinal strain predicted a T2* value of <20 ms with a sensitivity of 76% and a specificity of 88%.

Conclusion Myocardial mechanics offers a simple alternative to cardiac MRI for assessing significant myocardial iron deposition.

  • Echocardiography
  • myocardial mechanics
  • strain
  • cardiac magnetic resonance
  • speckle tracking
  • diastolic dysfunction
  • MRI
  • tissue doppler

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Footnotes

  • Competing interests None.

  • Ethics approval This study was conducted with the approval of the hospital research and ethics board.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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