Issue 16

R. Laczkó et alii, Frattura ed Integrità Strutturale, 16 (2011) 28-33; DOI: 10.3221/IGF-ESIS.16.03 28 Damages to stent stabilized left ventricular pacemaker electrodes during simulated lead extraction Romola Laczkó, Tibor Balázs, Eszter Bognár BME, Dept. of Materials Science and Engineering. H-1111 Budapest, Bertalan L. u. 7. Hungary János Ginsztler Research Group for Metals Technology of HAS and BME, 1111 Budapest, Goldmann ter 3. Hungary A BSTRACT . During biventricular pacemaker implantation stents can be applied for coronary sinus lead stabilization to prevent lead dislocations. A lot of issues have been raised in connection with the use of the stent. In some cases the implanted left ventricular lead must be explanted. It is crucial to avoid any injury to the heart when the electrode is removed. Another very important question concerns the type of injuries the electrode may cause during the removal process. An extraction model has been prepared using a special curve and a polymer tube. After the pacemaker leads were extracted, various microscopic examinations were executed. The findings may to make such intervention methods more successful, helping to better stabilize the electrode and to keep injuries during interventions to a minimum. K EYWORDS . Coronary stent; Left ventriculal pacemaker electrode; Simulated lead extraction. I NTRODUCTION pacemaker (PM) is an electronic device implanted in the body to regulate the heart beat. It consists of a battery and electronic circuits enclosed in a hermetically sealed can. The PM delivers electrical stimuli over leads with electrodes in contact with the heart [1]. Fig. 1 shows an X-ray picture of an implanted pacemaker system in a human chest. Cardiac resynchronization refers to stimulation techniques that change the degree of atrial and ventricular electromechanical asynchrony in patients with major intra-atrial or interatrial and ventricular conduction disorders. More recently for the treatment of heart failure, the left ventricle may be paced by inserting a lead into a tributary of the coronary sinus, a venous structure on the epicardial surface of the left ventricle [1]. Despite major advances of lead and pacemaker techniques, the implantation of a biventricular pacemaker is still a challenging and complex procedure. Introducing the left ventricular pacing lead into the sinus coronaries may cause difficulties. The dislocation rate of coronary sinus (CS) leads used for biventricular stimulation is high. Stent implantation to stabilize the left ventricular lead is a useful and safe procedure in the treatment of CS lead instability. The electrode is positioned into the desired position, and a metal coronary stent is introduced via a guide wire through the coronary sinus. After pacing measurements the stent is deployed at 5 to 30 mm proximal to the tip of the electrode [2]. Fig. 2 presents the parts of a steroid eluting pacemaker head. There is a risk of incidents, especially infections when the implanted left ventriculum lead is to be explanted. Therefore, it is crucial to avoid any injury to the heart when the electrodes are removed. During the process of removal the vein wall may be injured. To avoid this, it is to be decided first if the electrode can be explanted as the stent may damage the A