title: Value of speckle tracking echocardiography for detection of clinically silent left ventricular dysfunction in patients with β-thalassemia.
abstract: OBJECTIVE
  β-Thalassemia is an inherited hemoglobin disorder resulting in chronic hemolytic anemia requiring chronic transfusion therapy. Cardiac involvement is the main cause of death in patients with thalassemia major. The narrow border is between overt myocardial dysfunction and clinically silent left ventricular (LV) dysfunction in patients with thalassemia. Therefore, we need novel parameters in different imaging techniques to discover cardiac involvement in an early and subtle stage. We explore to find a novel, straightforward and informative parameter in echocardiography as a noninvasive, economical and really routine in clinical practice.
  
  
  METHODS
  In this prospective study, 55 patients, who are known cases of β-thalassemia major, receiving long-term blood transfusions and undergoing iron chelation therapy were enrolled. Ferritin level, cardiac magnetic resonance (CMR) T2 * value, full conventional echocardiography and speckle tracking, LV regional circumferential and longitudinal strain values (%) and time-to-peak strain (ms) of 17 segments cardiac model in eyeball tomogram were measured.
  
  
  RESULTS
  There was a significant reduction in global longitudinal strain (GLS) (-20.9% ± 1.9 vs. -22.2 ± 1.03) and also basal segments longitudinal strain compared to normal subjects group (-17.4% ± 2.7 vs. -19.6% ± 1.2). There was no significant difference in circumferential strain value between thalassemia patients and normal control group. Interestingly, there was no significant correlation between GLS and CMR T2 * values showing no association between cardiac iron load and longitudinal strain.
  
  
  CONCLUSIONS
  Speckle tracking echocardiography could be used as a feasible method for evaluating subclinical myocardial dysfunction in patients with thalassemia major. Echocardiography, using GLS, could predict clinically silent myocardial dysfunction independent of CMR (T2 * value) and extension of iron deposition. Our study also puts forward other causes such as chronic tissue hypoxia resulting from chronic anemia as a root cause and initiating factor for subsequent injury by the iron deposition. Speckle tracking can recognize the cardiac involvement in really early stages.
authors.affiliation: a Echocardiography Research Center, Rajaei Cardiovascular , Medical and Research Center , Tehran , Iran.
authors.forename: Mozhgan
authors.initials: M
authors.lastname: Parsaee
authors.affiliation: b Rajaei Cardiovascular Medical and Research Center , Iran University of Medical Sciences , Tehran , Iran.
authors.forename: Sedigheh
authors.initials: S
authors.lastname: Saedi
authors.affiliation: c Department of Echocardiography, Rajaei Cardiovascular, Medical and Research Center , Iran University of Medical Sciences , Tehran , Iran.
authors.forename: Pegah
authors.initials: P
authors.lastname: Joghataei
authors.affiliation: d Blood Transfusion Research Center , Tehran , Iran.
authors.forename: Azita
authors.initials: A
authors.lastname: Azarkeivan
authors.affiliation: e CMR Department, Rajaei Cardiovascular Medical and Research Center , Iran University of Medical Sciences , Tehran , Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Alizadeh Sani
mesh_terms: D000328:Adult; D015415:Biomarkers; D003131:Combined Modality Therapy; D004452:Echocardiography / Q000379:methods; D005260:Female; D006334:Heart Function Tests; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011446:Prospective Studies; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000503:physiopathology; D055815:Young Adult; D017086:beta-Thalassemia / Q000150:complications* / Q000175:diagnosis / Q000628:therapy
chemical_list: D015415:Biomarkers
keywords: Thalassemia; cardiac MR T2 *; circumferential strain; longitudinal strain; speckle tracking echocardiography