Systolic Dyssynchrony Index derived from cardiac magnetic resonance imaging predicts left ventricular remodeling in heart failure patients undergoing CRT
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KeywordsCardiac Magnetic Resonance Dilate Cardiomyopathy Cardiac Resynchronization Therapy Heart Failure Patient Cardiac Magnetic Resonance Imaging
It is known that 30-40% of heart failure patients that undergo cardiac resynchronization therapy (CRT) do not derive significant clinical benefit. Using cine imaging a measure of volume change over the cardiac cycle can be derived called the Systolic Dyssynchrony Index (SDI). This has the potential to improve patient selection pre CRT.
We assessed the potential of the SDI derived from CMR to predict reduction in end systolic volume (ESV) and improvement in ejection fraction in heart failure patients undergoing CRT.
42 heart failure patients (38 male, ejection fraction 26±8.9%, NYHA 2.8±0.4), 21 with ischemic cardiomyopathy (ICM) and 21 with dilated cardiomyopathy (DCM) underwent a CMR prior to CRT implantation. Patients were scanned using 1.5T MR-scanner (Achieva, Philips Healthcare, Best, Netherlands) with either 32 or 5-element cardiac coil. Cine steady state free precession (cine-SSFP) images of four, three, two chamber as well as a multiple slice short axis stack were acquired (FA=60°, TR/TE=2.9/1.5ms, resolution 2.2x2.2x10mm, 30 heart phases). Using TomTec 4D LV-Analysis MR (TT4DMR) we derived a 16 segment systolic dyssynchrony index (SDI). 2D echo pre and 6 months post CRT implantation was used to assess change in EF and ESV. Patients were considered to have remodeled if there was 15% reduction in ESV. Furthermore ≥ 15% improvement in EF was also considered as responding to CRT. An SDI of 10.3% was used to calculate sensitivity and specificities.
Shows the change in ESV and EF pre and post CRT
Patients with SDI > 10.3
Patients with SDI < 10.3
Ejection Fraction (%)
End Systolic Volume (ml)
SDI derived from CMR is highly predictive at selecting which patients are likely to remodel post CRT. This may be clinically useful to help identify which patients are likely to responders to CRT.
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