CAPABILITIES OF 123I-MIBG SCINTIGRAPHY AND GATED BLOOD-POOL SPECT IN PREDICTING THE RESULTS OF CARDIAC RESYNCHRONIZATION THERAPY

Purpose.To assess the diagnostic value of scintigraphy parameters of sympathetic activity and mechanical dyssynchrony of the heart for prediction of the results of cardiac resynchronization therapy (CRT).Material and Methods.The study included 28 patients with functional class III (NYHA) chronic heart failure referred for CRT. Before operation, a set of scintigraphic studies was performed to evaluate mechanical dyssynchrony, the state of cardiac sympathetic innervation, and perfusion. Clinical status, volume indices, and contractility of both cardiac ventricles were evaluated 6 months after CRT. After that, all patients were divided into 2 groups: group 1 included CRT responders (n=15); group 2 comprised non-responders (n=13).Results. Significant differences between groups were found in the following baseline parameters: early heart-to-mediastinum ratio (H/M) (2.42 and 1.87; p<0.05), delayed H/M (1.89 and 1.78; p<0.05), left ventricular (LV) end-diastolic volume (EDV) (271 mL and 299 mL; p<0.05); LV end-systolic volume (ESV) (206 mL and 227 mL; p<0.05), and interventricular dyssynchrony (109 ms and 62 ms; p<0.05). Responders showed a strong correlation between delayed H/M and LV dyssynchrony (–0.795, p<0.05). According to logistic regression analysis, delayed H/M (OR=4.25; 95% CI 1.4–12.92; p<0.5) and interventricular dyssynchrony (OR=1.01; 95% CI 1.003–1.03; p<0.5) were statistically significant determinants of the response to CRT.Conclusion. 123I-MIBG myocardial scintigraphy can be used to predict the effectiveness of CRT. Delayed H/M ratio and interventricular dyssynchrony are the independent predictors of response to CRT.