title: Subclinical cardiac dysfunction detected by strain imaging during breast irradiation with persistent changes 6 weeks after treatment.
abstract: OBJECTIVE
  To evaluate 2-dimensional strain imaging (SI) for the detection of subclinical myocardial dysfunction during and after radiation therapy (RT).
  
  
  METHODS
  Forty women with left-sided breast cancer, undergoing only adjuvant RT to the left chest, were prospectively recruited. Standard echocardiography and SI were performed at baseline, during RT, and 6 weeks after RT. Strain (S) and strain rate (Sr) parameters were measured in the longitudinal, circumferential, and radial planes. Correlation of change in global longitudinal strain (GLS % and Δ change) and the volume of heart receiving 30 Gy (V30) and mean heart dose (MHD) were examined.
  
  
  RESULTS
  Left ventricular ejection fraction was unchanged; however, longitudinal systolic S and Sr and radial S were significantly reduced during RT and remained reduced at 6 weeks after treatment [longitudinal S (%) -20.44 ± 2.66 baseline vs -18.60 ± 2.70* during RT vs -18.34 ± 2.86* at 6 weeks after RT; longitudinal Sr (s(-1)) -1.19 ± 0.21 vs -1.06 ± 0.18* vs -1.06 ± 0.16*; radial S (%) 56.66 ± 18.57 vs 46.93 ± 14.56* vs 49.22 ± 15.81*; *P<.05 vs baseline]. Diastolic Sr were only reduced 6 weeks after RT [longitudinal E Sr (s(-1)) 1.47 ± 0.32 vs 1.29 ± 0.27*; longitudinal A Sr (s(-1)) 1.19 ± 0.31 vs 1.03 ± 0.24*; *P<.05 vs baseline], whereas circumferential strain was preserved throughout. A modest correlation between S and Sr and V30 and MHD was observed (GLS Δ change and V30 ρ = 0.314, P=.05; GLS % change and V30 ρ = 0.288, P=.076; GLS Δ change and MHD ρ = 0.348, P=.03; GLS % change and MHD ρ = 0.346, P=.031).
  
  
  CONCLUSIONS
  Subclinical myocardial dysfunction was detected by 2-dimensional SI during RT, with changes persisting 6 weeks after treatment, though long-term effects remain unknown. Additionally, a modest correlation between strain reduction and radiation dose was observed.
authors.affiliation: University of New South Wales, Sydney, NSW, Australia; Liverpool Hospital, Sydney, NSW, Australia.
authors.forename: Queenie
authors.initials: Q
authors.lastname: Lo
authors.affiliation: University of New South Wales, Sydney, NSW, Australia; Liverpool Hospital, Sydney, NSW, Australia; Ingham Institute of Applied Medical Research, Liverpool, NSW, Australia.
authors.forename: Leia
authors.initials: L
authors.lastname: Hee
authors.affiliation: University of New South Wales, Sydney, NSW, Australia; Liverpool Hospital, Sydney, NSW, Australia; Ingham Institute of Applied Medical Research, Liverpool, NSW, Australia.
authors.forename: Vikneswary
authors.initials: V
authors.lastname: Batumalai
authors.affiliation: Liverpool Hospital, Sydney, NSW, Australia.
authors.forename: Christine
authors.initials: C
authors.lastname: Allman
authors.affiliation: University of New South Wales, Sydney, NSW, Australia; St. Vincent's Hospital, Sydney, NSW, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: MacDonald
authors.affiliation: University of New South Wales, Sydney, NSW, Australia; Liverpool Hospital, Sydney, NSW, Australia; Ingham Institute of Applied Medical Research, Liverpool, NSW, Australia.
authors.forename: Geoff P
authors.initials: GP
authors.lastname: Delaney
authors.affiliation: Liverpool Hospital, Sydney, NSW, Australia; Ingham Institute of Applied Medical Research, Liverpool, NSW, Australia.
authors.forename: Denise
authors.initials: D
authors.lastname: Lonergan
authors.affiliation: University of New South Wales, Sydney, NSW, Australia; Liverpool Hospital, Sydney, NSW, Australia. Electronic address: l.thomas@unsw.edu.au.
authors.forename: Liza
authors.initials: L
authors.lastname: Thomas
mesh_terms: D000704:Analysis of Variance; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D054459:Elasticity Imaging Techniques; D005260:Female; D006321:Heart / Q000528:radiation effects*; D006801:Humans; D008408:Mastectomy / Q000379:methods; D008875:Middle Aged; D011446:Prospective Studies; D011829:Radiation Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D018714:Radiotherapy, Adjuvant; D013318:Stroke Volume / Q000502:physiology / Q000528:radiation effects; D013599:Systole / Q000502:physiology / Q000528:radiation effects; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology