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Cardiovascular: Clinical ScienceRisk Stratification, Guiding Therapy and Follow-up |
1 UCSF, San Francisco, California
511
Objectives: Synchrony (S) and Entropy (E) are novel equilibrium radionuclide angiogram derived measures of dyssynchrony described in pts with heart failure (HF). S is the vector sum for all pixels in a region divided by the sum of all amplitudes, where the phase and amplitude of each pixel define its vector. E is a measure of the flatness of the phase histogram or the randomness of its distribution. We measured S and E in HF pts undergoing cardiac resynchronization therapy (CRT) and correlated serial changes with clinical outcomes.
Methods: We studied 46 pts (32 males, mean age 63+/- 14 years) with advanced HF and LVEF 
35%. ERNA was performed and HF status was evaluated before and after CRT. Pts were followed for > 6 months and were graded 2 (n=15), 1 (n=18) or 0 (n=13) based on improvement in NYHA class. This was then correlated to changes in LVEF, standard deviation of phase (SD Ø), S, and E.
Results: The patients classified 2 showed large improvements in S and E, less in LVEF, and least in SD of Ø. While change in LVEF and SD Ø could separate patients who improved 2 NYHA classes, it was not sensitive enough to identify moderate clinical improvement and differentiate it from no improvement. A change in S was the only statistically significant parameter (p< 0.02) that differentiated pts in grade 1 from grade 0.
Conclusions: S and E are novel ERNA derived parameters of LV dyssynchrony that show significant correlation with clinical outcomes in HF pts.
Research Support: Philips, Inc - Grant
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