The Use of Myocardial Deformation Imaging
Condition: Myocardial Viability in Ischemic Left Ventricular Dysfunction; Prediction for Improvement in Cardiac Function After Revascularization Therapy
MeSH terms: Ventricular Dysfunction; Ventricular Dysfunction, Left
Study type: Observational

Summary: 
      Myocardial deformation imaging allows analysis of myocardial viability in ischemic left
      ventricular dysfunction. This study will evaluate the predictive value of myocardial
      deformation imaging for improvement in cardiac function after revascularization therapy in
      comparison to contrast-enhanced cardiac magnetic resonance imaging (ceMRI).

      In 55 patients with ischemic left ventricular dysfunction, myocardial viability was assessed
      using pixel-tracking-derived myocardial deformation imaging and ceMRI to predict recovery of
      function at 9±2 months follow-up. For each left ventricular segment in a 16-segment model
      peak systolic radial strain will be determined from parasternal 2D echocardiographic views
      and the amount of late hyperenhancement (LE) and maximal thickness of myocardial tissue
      without LE using ceMRI. The hypothesis is that compared with segments showing functional
      improvement, those that failed to recover had lower radial strain and lower thickness without
      LE and higher LE.
    

Detailed description: 
      Between August 2004 and June 2006 195 patients with ischemic left ventricular dysfunction
      underwent MRI for the definition of myocardial viability. Onehundred-ten patients with
      non-ischemic cardiomyopathy or acute coronary syndromes were excluded from the study to avoid
      possible acute ischemia or stunning. Within the 85 patients with chronic ischemic heart
      disease, six patients refused participation in this study and five patients had
      echocardiographic windows insufficient for participation. Within the remaining 74 patients 55
      patients underwent revascularization and 19 had no revascularization. These 55 patients form
      our study group! Functional recovery will be assessed using echocardiographic images before
      and 9±2 months after revascularization with a Vivid Seven System (GE Vingmed, Horton,
      Norway). Parasternal long-axis and short-axis views at basal, midventricular and apical
      levels, as well as 3 standard apical views (4 chamber, 2 chamber, and long axis) have been
      acquired (frame rate 56 to 92 frames/s). Segmental wall motion will be determined using the
      following score: 1=normokinetic, 1.5= mildly hypokinetic, 2= moderately or severely
      hypokinetic, 3= akinetic, or 4= dyskinetic. A segment is considered to demonstrate functional
      improvement during follow-up if it improved by at least 1 grade. Global functional recovery
      was considered in case of an increase in ejection fraction>5% at follow-up.

      The three acquired parasternal short axis views will be analysed with the aid of a dedicated
      software package (EchoPAC BT 05.2, GE Vingmed, Horton, Norway). This system allows analysis
      of peak systolic circumferential and radial strain from short axis views based on detection
      of natural acoustic markers. The system calculates mean strain values for whole predefined LV
      segments, including all myocardial layers from the endocardium to epicardium.

      All patients underwent cMRI within a few hours of the baseline echocardiographic study on a
      1.5-T whole-body MR scanner (Intera, Best, Philips, the Netherlands). The assignment to a
      hyperenhancement category reflects the extent of hyperenhancement within each segment by
      visual assessment considering a 5-group scale: 0% hyperenhancement (group 1), 1 to 25%
      hyperenhancement (group 2), 26 to 50% hyperenhancement (group 3), 51 to 75% hyperenhancement
      (group 4) and 76 to 100% hyperenhancement (group 5).

      In addition, the maximal thickness of myocardial tissue without late hyperenhancement will be
      determined for each LV segment. This is considered to be a parameter of the remaining viable
      myocardium.
    

Intervention name(s): Magnetic Resonance Imaging; Revascularization; Echocardiography with myocardial deformation imaging
Intervention type(s): Procedure; Procedure; Procedure
Observational model: Defined Population
Time perspective: Other
Keywords: echocardiography; myocardial infarction; magnetic resonance imaging; revascularization; viability