Abstract
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Objectives Cardiac re-synchronization therapy (CRT) is now widely applied for the patients with severe heart failure. However, the significance of systolic dyssynchrony and diastolic dssynchrony is not clear. The aim of this study is to reveal the significance of the diastolic dyssynchrony in symptoms of the patients with severe heart failure.
Methods Thirty-eight patients with CRT or CRT-D were enrolled to this study after well informed consent. To measure the systolic and diastolic dyssynchrony of the left ventricle during CRT-on and CRT-off, sixteen gated myocardial perfusion SPECT was performed during CRT-on and CRT-off. Regional peak thickening phase and peak thinning phase was measured using a count based method with 3rd harmonic furrier analysis and displayed on the polar map as a color scale. We obtained standard deviation (SD) of peak thickening phase of all regions as a parameter of systolic dyssynchrony and SD of peak thinning phase of all regions as a parameter of diastolic dyssynchrony. Peak ejection rate and peak filling rate of LV were calculated using LV volume curve derived from QGS analysis. The BNP and specific activity scale (SAS) was measured before and after CRT implantation.
Results Improvement of peak thinning phase SD is positively correlated with decrease of BNP(R=0.75, P<0.05). Improvement of peak thinning phase SD is also positively correlated with improvement of SAS(R=0.68, P<0.05). On the other hand, Improvement of peak thinning is positively correlated with improvement of peak filling rate. Twenty six patients gained more than 2.0 in SAS, which are named responders. In the responders, peak thinning phase SD is significantly decreased during CRT-on(70±24 vs 45±18, degree, P<0.01), but peak thickening shows no significant difference(86±37 vs 78±41, degree, ns).
Conclusions Acceleration of the early diastolic filling by CRT is important for improving symptoms of heart failure.