ngực cine fluoroscopic postero-trước (PA) xem trường hợp tương tự như Hình . Những mẹo của người giới thiệu dài (bị phá vỡ vòng tròn màu đen) đã được thông qua gần như đường giao nhau của cấp trên tĩnh mạch chủ và tâm nhĩ phải | 36 Chapter 10 Figure Chest cine fluoroscopic postero-anterior PA view of the same case as Figure . Using a long introducer the lead has been passed beyond the brachiocephalic innominate -superior vena caval junction and now passes easily into the right atrium. PA Figure Chest cine fluoroscopic postero-anterior PA view of the same case as Figure . The tip of the long introducer black broken circle has been passed almost to the junction of the superior vena cava and right atrium. Through this introducer the lead has been passed into the mid right atrium five white arrows but cannot progress further. The procedure was abandoned on the left side. previously implanted leads turn to enter the brachiocephalic or innominate vein. The vein at this point is often large and patent because of the confluence of the jugular and subclavian veins. Even after successful venous puncture and entry it is often very difficult to get a standard stiff introducer guide wire or pacemaker lead into the right atrium. The vein is thickened with narrowings or shelves on which the Stenosed venous channels 37 Figure Chest cine fluoroscopic postero-anterior PA views of the same case as Figures and . Left The long introducer has now been passed from the right side and the tip lies in the upper right atrium black broken circle . Right A venogram shows a very narrow passageway through the right atrium due to probable extensive thrombosis and fibrosis black broken circle . Figure Chest cine fluoroscopic postero-anterior PA views of the same case as Figures and . Left A ventricular active-fixation lead has been passed through the long introducer and lies near the floor of the right atrium white arrows . Right The ventricular lead has been passed with much difficulty to the apex of the right ventricle below the original lead white arrow . guide wires or leads get caught Figure . A stiff guide wire may perforate the vein and enter the mediastinum .
