Echocardiography & Gated Myocardial Perfusion SPECT Imaging: more common grounds in localizing dyssynchrony prior to CRT

1536 Objectives Global synchrony measures, calculated using phase analysis in gated myocardial perfusion SPECT (MPS), have been shown to correlate with tissue Doppler imaging-derived measures of dyssynchrony and to predict response to cardiac resynchronization therapy (CRT). Our aim was to determine concordance between speckle tracking ECHO and SPECT for the determination of the latest activated LV segment Methods Out of 187 patients enrolled in the STARTER trial, 54 had both ECHO and SPECT at baseline and were included in this study. ECHO and SPECT were read by blinded interpreters using a 17-segment model. Patients were grouped into Group 1 if both modalities detected the same or adjacent latest activated segment; Group 2 if the difference was more than one segment apart. Amplitude, defined as the magnitude of myocardial contraction, was obtained from MPS phase analysis. Logistic regression was used for analysis. Results Compared to Group1, Group2 patients had elevated end diastolic (EDV) and end systolic volumes (ESV) (347 and 272 vs. 240 and 167, P=0.01 and P=0.006 respectively) and more depressed EF (33 vs. 24%, P=0.004) (Table 1). Group2 patients also had lower global synchrony (86 vs. 94%, P=0.03) and wider histogram bandwidth (103 vs. 81 degrees, P=0.077). After adjusting for age, gender, histogram bandwidth, and global synchrony, discordance between ECHO and SPECT was 13% lower with higher EF (OR=0.88, CI 0.79-0.97, P=0.01). 12/20 (60%) discordant patients had the latest activated LV segment in the septum/apex and of those 8 (67%) patients had the lowest amplitude in these same delayed segments. Conclusions SPECT and ECHO are concordant in the majority of CRT patients in their assessment of the latest activated LV segment. Discordance is associated with the degree of LV dysfunction and the regional location of the latest activated segment.