title: Dobutamine stress MRI in repaired tetralogy of Fallot with chronic pulmonary regurgitation: a comparison with healthy volunteers.
abstract: BACKGROUND
  To compare the ventricular response to dobutamine stress between adult patients with chronic pulmonary regurgitation (PR) after repair of tetralogy of Fallot (r-TOF) and healthy volunteers using a staged dobutamine stress MR (DS-MR) protocol.
  
  
  METHODS
  Eighteen r-TOF patients (median age 31.9 years, range 16.2-60.1) with severe PR and 10 healthy controls (median age 40.6 years, range 23.9-51.8) completed staged DS-MR (baseline, 10 and 20 μg/kg/min) with ventricular volumetry and pulmonary flow quantification. Comparative analysis involved 3-way ANOVA, t-test, regression analysis, and coefficient of variance.
  
  
  RESULTS
  All controls had significant increase of ejection fraction (EF) at each stress level for both ventricles (normal contractile reserve, all p<0.05). In r-TOF patients (RV-EDV 126 ± 27 ml/m(2), RV-EF 55 ± 7%, LV-EF 58 ± 6%, PR-fraction 43 ± 15%), low-dose DS-MR at 10 μg/kg/min demonstrated normal biventricular contractile reserve as seen in volunteers. On increase from 10 to 20 μg/kg/min a subgroup showed worsening ejection fraction (n=8, p<0.05), mainly due to lack of reduction or even increase of RV-ESV, while the remainder responded with further reduction of RV-ESV and RV-EDV (n=10, p<0.05) and a non-significant trend to increased EF. This different response could not be predicted at baseline.
  
  
  CONCLUSIONS
  In r-TOF patients with chronic PR, DS-MR at 10 μg/kg/min showed normal biventricular systolic response compared with controls. Increase to 20 μg/kg/min provoked abnormal RV-ESV response in some r-TOF patients, suggesting presence of ventricular systolic dysfunction not evident at rest.
authors.affiliation: King's College London BHF Centre, Division of Imaging Sciences, NIHR Biomedical Research Centre at Guy's & St Thomas' NHS Foundation Trust, UK. victoria.parish@kcl.ac.uk
authors.forename: Victoria
authors.initials: V
authors.lastname: Parish
authors.forename: Israel
authors.initials: I
authors.lastname: Valverde
authors.forename: Shelby
authors.initials: S
authors.lastname: Kutty
authors.forename: Catherine
authors.initials: C
authors.lastname: Head
authors.forename: Shakeel A
authors.initials: SA
authors.lastname: Qureshi
authors.forename: Samir
authors.initials: S
authors.lastname: Sarikouch
authors.forename: Gerald
authors.initials: G
authors.lastname: Greil
authors.forename: Tobias
authors.initials: T
authors.lastname: Schaeffter
authors.forename: Reza
authors.initials: R
authors.lastname: Razavi
authors.forename: Philipp
authors.initials: P
authors.lastname: Beerbaum
mesh_terms: D000293:Adolescent; D000328:Adult; D002908:Chronic Disease; D025401:Echocardiography, Stress / Q000379:methods*; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011665:Pulmonary Valve Insufficiency / Q000175:diagnosis* / Q000503:physiopathology; D013771:Tetralogy of Fallot / Q000503:physiopathology / Q000601:surgery*; D055815:Young Adult