title: Changes in systolic left ventricular function in isolated mitral regurgitation. A strain rate imaging study.
abstract: OBJECTIVE
  The aim of the present study is to understand the changes in left ventricular (LV) regional systolic deformation based on strain rate (SR) imaging in patients with isolated mitral regurgitation (MR). Progressive LV dilatation and irreversible myocardial damage as a result of chronic isolated MR are important causes of morbidity and mortality in patients following valve surgery. To date, there is no specific diagnostic method to detect subclinical changes in systolic function before irreversible dysfunction occurs.
  
  
  RESULTS
  Seventy-seven individuals were studied: 54 asymptomatic patients (age 56 +/- 12) with isolated non-ischaemic MR divided into three groups: mild, moderate, and severe and 23 healthy subjects. All underwent a standard echo examination and a tissue Doppler study. A mathematical study was carried out to predict how SR should alter with increasing dimensions and due to irreversible myocardial damage. Radial as well as longitudinal peak systolic SR was significantly decreased in patients with severe MR compared to the other groups (LV posterior wall: P = 0.0006, septum: P = 0.0004, LV lateral wall: P = 0.0003). From both modelling and in our patients, deformation correlated inversely with LV end-diastolic diameter and end-systolic diameter (ESD). Deformation measurements (corrected for increased geometry) enabled the identification of patients classically referred to as at risk of irreversible myocardial damage (ESD > or = 4.5 cm).
  
  
  CONCLUSIONS
  In patients with a wide range of MR, deformation remains unchanged due to a balance of increased dimensions and increased stroke volume. Only when contractility is expected to change, deformation will significantly decrease. SR imaging indices, corrected for geometry, might potentially be useful in detecting subclinical deterioration in LV function in asymptomatic patients with severe MR.
authors.affiliation: Department of Cardiology and Cardiothoracic Surgery, St George's Hospital, London, UK.
authors.forename: Anna
authors.initials: A
authors.lastname: Marciniak
authors.forename: Piet
authors.initials: P
authors.lastname: Claus
authors.forename: George R
authors.initials: GR
authors.lastname: Sutherland
authors.forename: Maciej
authors.initials: M
authors.lastname: Marciniak
authors.forename: Tiia
authors.initials: T
authors.lastname: Karu
authors.forename: Aigul
authors.initials: A
authors.lastname: Baltabaeva
authors.forename: Elisa
authors.initials: E
authors.lastname: Merli
authors.forename: Bart
authors.initials: B
authors.lastname: Bijnens
authors.forename: Marjan
authors.initials: M
authors.lastname: Jahangiri
mesh_terms: D004452:Echocardiography / Q000379:methods; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000503:physiopathology*; D015203:Reproducibility of Results; D013318:Stroke Volume / Q000502:physiology; D013599:Systole / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology*