Purpose: The aim of the study was to evaluate the quality of radiofrequency (RF)-induced cardiac denervation by using non-invasive methods.
Materials and Methods: The study included 19 patients with NYHA functional class III/IV heart failure (mean age: 60 ± 9.4 years). All patients underwent surgical treatment of valvular diseases. Patients were assigned to two groups: group 1: 11 patients with AF who underwent RF maze procedure with destruction of paraganglionic nervous plexuses; group 2: 8 patients with SR without denervation. All patients received examination of cardiac sympathetic tone by scintigraphy using 123I- metaiodobenzylguanidine (123I-MIBG).
Results: Before surgery, patients with AF had significantly lower heart-to-mediastinum (H/M) ratio (1.64 ± 0.21 vs. 1.9 ± 0.27; p < 0.05) and significantly higher indicator washout rate (30.21 ± 10.43% vs. 21.94 ± 15.01%; p < 0.05) compared with group of patients with sinus rhythm. According to data of regional sympathetic activity evaluation, patients of both groups had similar defects in accumulation of 123I-MIBG before surgery (11.1 ± 5.6% vs. 8.9 ± 5.0%; p = 0.057). Patients with cardiac denervation showed a significant decrease in H/M indexes compared with the corresponding values before surgery (1.64 ± 0.21 vs. 1.42 ± 0.18; p < 0.05). Defect of accumulation significantly increased (11.1 ± 5.6% vs. 24.9 ± 7.56; p < 0.05). Patients without denervation had statistically significant decrease only in H/M index (1.9 ± 0.27 vs. 1.63 ± 0.24; p < 0.5). The study showed that washout rate of 123I-MIBG significantly changed after surgery (36 ± 13.38% vs. 25.14 ± 9.96%; p < 0.05). Patients with AF had significantly lower H/M index compared with group of patients with sinus rhythm (1.42 ± 0.18 vs. 1.63 ± 0.24; p < 0.05). Evaluation of regional sympathetic activity showed that 123I-MIBG accumulation defect was significantly larger in patients with cardiac denervation compared with group of patients without it (24.9% ± 7.56% vs. 13.7 ± 5.81%; p < 0.05).
Conclusions: Data of the study showed that patients who underwent destruction of paraganglionic nervous plexuses had statistically significant increase of 123I-MIBG washout rate, decrease of H/M index on early and delayed scintigrams, and increase of 123I-MIBG accumulation defect suggesting that this method may be used for the quality evaluation of cardiac sympathetic denervation in the postoperative period.