In Furman and Young were the first
In 1977, Furman and Young  were the first to report on transvenous pacemaker lead faah inhibitors in 12 children and adolescents. The youngest patient was 1 month old. After their report, several other papers on endocardial pacemaker implantation in small children were published (Table 2) [2,3,6–11]. Gillette et al.  reported transvenous pacing from the subclavian vein via puncture. The criteria for transvenous pacemaker lead implantation were that the patient should be >4 years of age with a body weight >15kg. Till et al.  reported that smaller pacemaker generator and transvenous lead established transvenous ventricular pacing (VVI) in a newborn infant of 2.8kg and atrioventricular synchronized pacing (DDD) in children at the age of 3 years and 12.8kg body weight. Guerola et al.  reported 7 cases of children who underwent dual-chamber pacemaker lead implantation with unipolar leads via subclavian vein puncture. The body weight at operation was <4kg and minimum body weight was 1.2kg. There was a subclavian vein thrombosis in a 1.2kg neonate and nearly all the patients required lead advancement prior to generator end-of-life. Sachweh et al.  and Strojanov et al.  reported transvenous pacemaker lead implantation via the cephalic vein by cutdown. Sachweh et al.  recommended that the transvenous lead should be inserted via puncture of the subclavian vein if the cephalic vein was too small in diameter or forward movement of the lead was impossible. Kammeraad et al.  reported endocardial lead implantation via subclavian vein puncture in infants who weighed <10kg (the minimum body weight was 2.3kg). Molina et al.  reported that the entry vein should be carefully selected according to patient age and that the size of the entry vein should also be checked using vascular echo due to variations in size. Furthermore, they reported that vein obstruction frequently occurs for large endocardial leads occupying more than half of the cross-sectional area of the entry vein. The entry vein should thus have a cross-sectional area of more than twice the sum of the cross-sectional areas of 2 leads if 2 leads for DDD pacing are chosen. Bar-Cohen et al.  recently assessed the rate of venous obstruction after pacemaker implantation for small children using a venogram and concluded that age, size, and lead factors alone do not predict venous obstruction. New leads could be placed by advancing a wire past the obstruction, thus bypassing the obstruction, or by advancing the new leads through tracts created by extracted leads. However, the presence of venous occlusion increases the procedural complexity in many of the cases. Therefore, we have to choose a larger vein and to select a smaller lead to decrease venous obstruction. We opted for a screw-type lead to prevent lead detachment, as Williams et al.  reported a case in which a tined lead became free-floating in the late phase. Advancements in technology facilitate the use of smaller diameter endocardial leads. According to the 2012–2013 Data Book Pacemaker & ICD/CRT, the diameter of FINELINE™ II Storox (Boston Scientific, Natick, MA, USA) and Tendril™ (St. Jude Medical Inc., St. Paul, MN, USA) is less than 2mm. Unfortunately, we have no experience of using Tendril for small children. FINELINE is a 1.7mm, bipolar, screw-in pacing lead. This lead can be inserted into the vein using a 5 Fr sheath or directly by cutdown. This lead does not have a retractable screw-in system. A small amount of sugar covers the fixed helix for the first 5min in the bloodstream. Thus, this lead must be attached to the right atrium or right ventricle before the sugar dissolves to prevent entanglement with the tricuspid valve apparatus. The body of the lead also has to be rotated to fix it to the myocardium, which is not very difficult; however, it is occasionally difficult to detach the lead from the myocardium to identify a better pacing and sensing site. Recently, the SelectSecure™ model 3839 lead (Medtronic Inc.) has become commercially available in Japan. The SelectSecure is a 4.1 Fr, steroid-eluting, bipolar, fixed-screw lumenless pacing lead. Its small size makes it beneficial for use in children. However, the delivery system, an 8.4 Fr steerable catheter requiring a 9 Fr introducer sheath, is not optimal for use in small children due to its size and its large radius of curvature. Lapage and Rhee  developed a 5 Fr checkFlo Performer™ Introducer set (Cook Medical Inc., Bloomington, IN, USA) to optimize delivery without the need for a large diameter introducer/sheath system. If we can use this delivery system, SelectSecure is then an attractive lead to use: the small outer diameter lead may prevent venous occlusion, the steroid-eluting lead may prevent increasing pacing threshold over time, and the lumenless lead may prevent lead fracture over time. During the 16-year follow-up period in our patient, no adverse phenomena, such as exit block, sensing failure, or free-floating of the lead, were observed, except for a gradual increase in pacing threshold. Intravenous pacemaker lead implantation has many advantages compared with a myocardial lead. It is important to avoid venous obstruction in the long term for good results after pacemaker lead implantation, especially in small children. A small-sized lead and an appropriate entry vein should be selected to avoid venous obstruction after lead implantation.