Histogram bandwidth is a better predictor than Echocardiographic Tissue Doppler peak systolic velocity for Cardiac Resynchronization Therapy response

Objectives The aim of this study is to compare degree of left ventricular dyssynchrony as assessed with phase analysis from Gated myocardial perfusion SPECT (GMPS) to that assessed with Echocardiographic Tissue Doppler Imaging (TDI) in patients with left ventricular EF <35%, QRS complex >120 ms. Patients & methodology 30 patients were included, all scheduled for CRT. TDI was measured as standard deviation of time to peak systolic velocity in 6 basal segments. Gated SPECT TC-99m sestamibi acquisition was performed, software phase analysis parameters is histogram bandwidth which include 95% of the element of the phase distribution. Study population was divided into two groups: responders and non-responders according to increase of at least 15% of LVEF after 3 months. Results ROC analysis was done to reveal that Phase analysis parameter acted in better way to predict CRT response with histogram bandwidth 55.5° Area Under Curve (AUC) 68.9% sensitivity 87% specificity 42.9% positive predictive value (PPV) 83.3% negative predictive value (NPV) 50% compared to TDI sensitivity 52.25%, specificity 71.4% PPV 85.7% NPV 31.3% When applying histogram bandwidth cutoff 55.5° dyssynchrony was illustrated in 20 (87%) patients in comparison to 14 (60%) patients with Echo TDI, there was significant difference in sensitivity of histogram bandwidth compared to TDI with p value 0.043. Conclusion Histogram bandwidth of GMPS Tc 99m sestamibi may be more predictive of significant response to CRT as compared to TDI.