Role of radionuclide assessment of global and regional mechanical dyssynchrony of the heart in prognosis of cardiac resynchronization therapy in patients with heart failure

Aim. To determine the prognostic significance of cardiac regional mechanical dyssynchrony (MD), assessed by radionuclide equilibrium ventriculography (REVG) in candidates for cardiac resynchronization therapy (CRT). Material and methods . The study included 65 patients with indications for CRT according to current guidelines. Prior to CRT, all patients underwent REVG to assess cardiac contractile function and MD. According to the phase analysis, indicators of global and regional cardiac MD were evaluated: phase standard deviation (PSD), histogram band width (HBW), entropy, and interventricular dyssynchrony. The regional assessment included an evaluation of phase histograms obtained from the analysis of the contraction of certain walls: left ventricular (LV) anterior, lateral, posterior wall, right ventricular (RV) free wall, and the interventricular septum. To evaluate the effectiveness of treatment 6 months after CRT, all patients underwent echocardiography, on the basis of which patients were divided into groups of responders and non-responders. Results. REVG revealed significant differences in the initial regional MD values between the groups of responders and non-responders: in responders, MD values of RV free wall (PSD: 39 (28-67) vs 28 (20-50), p=0,03) and LV anterior wall (PSD: 28,5 (16-40) vs 14 (11-24), p=0,0005) were higher, and the LV lateral wall was lower (PSD: 10 (7-14) vs 15 (9-26), p=0,007) than in non-responders. Multivariate logistic regression found following independent predictors of a positive response to CRT: heart failure of ischemic origin, LV HBW, RV free wall PSD, anterior wall PSD, LV lateral wall HBW (p<0,001). The sensitivity and specificity of the model was 93% and 91%, respectively. Conclusion. Regional MD scintigraphy parameters increase the predictive value of REVG in CRT candidates. The most informative in this regard are the PSD of RV free wall and LV anterior wall, as well as the HBW of LV lateral wall.