Possibilities of the merge technique for intraoperative imaging in a lead implantation into the cardiac conduction system for permanent cardiac pacing: interim results of the study

Introduction. A lead implantation into the cardiac conduction system (CCS) is currently the most physiological method of pacing. However, despite the availability of specialized lead and delivery systems, the proportion of non-targeted implantations is very significant. There is a need for an intraoperative visualization technique. The lead position is monitored by electrophysiological and fluoroscopic methods, which, obviously, are not enough.Aim: To optimize the implantation of leads in the conduction system of the heart through the use of intraoperative merge visualization technique (IVT).Material and methods. Two study groups are formed as part of the protocol of a prospective study. In the patients of the study group leads were implanted into the CCS using the IVT; in the control group - by traditional method. After implantation, in all patients the position of the lead using a transthoracic echocardiography (TTE), ECG was assessed. Computed tomography (CT) was performed in patients of study group before and after implantation. In patients of control group CT was performed after implantation.Results. The full study protocol was completed in 10 patients of the study group and in 10 patients of the control group. All patients of the study group confirmed the lead implantation into the interventricular septum (IVS) using TTE and CT; into the CCS using ECG. The duration of the surgery was 87.5 [70; 120] min, fluoroscopy time - 225 [125; 421] sec. Complications, non-target implantations were not registered. In the control group, the duration of the surgery was 100 [100;110] min, the time of fluoroscopy was 775 [500;1230] sec.; stimulation of the CCS was confirmed in 4 (40%) patients; recorded 2 (20%) cases of perforation of the IVS, 1 (10%) case of implantation in the area of the apical part of the right ventricle, 1 (10%) intraoperative dislocation of the right ventricular lead, 1 (10%) case of hemopericardium in the early postoperative period. The average measurement error according to the intraoperative imaging technique compared with MSCT: the distance from the LV endocardium to the lead was 0.98 ± 0.51 mm, the distance from the lead to the tricuspid valve ring was 3.1 ± 0.92 mm. According to trans-thoracic echocardiography, there weren’t structural and functional changes in the tricuspid valve, newly emerged local areas of the myocardium with impaired contractility were detected in patients of the two groups. There weren’t significant changes in sensitivity thresholds, stimulation, and postoperative dislocations of the leads.Conclusions. The use of IVT allows to reduce the number of “off-target” implantations, the time of fluoroscopy, the radiation exposure of the operator and the duration of the surgery.