In vitro biostability of cardiac pacemaker lead insulations under static mechanical loading

Abstract Patients with cardiac arrhythmias are currently treated conventional transvenous rhythm implants. Complications frequently associated intracardiac implanted leads primary insulated by silicone and polyurethane. However, experiences show that polyurethanes in particular susceptible to various degradation mechanisms including hydrolysis, environmental stress cracking (ESC) metal ion induced oxidation (MIO). In vivo, pacemaker exposed a complex thermal, chemical, mechanical biological loading. The current study focusses on vitro analyses assess the biostability of Pellethane 2363 55D MED 4765 as lead insulations. Degradation processes were simulated load-free state under static loading subjecting coaxial design bending radii from 3 mm 19 mm. Physiological conditions mimicked using physiological saline solution tempered oxidative solution. Surface morphological thermal performed before after testing means scanning electron microscopy (SEM) differential calorimetry. Melting temperatures silicones around 40°C measured, testing, respectively. insulation layers had two endothermal melting regions at 100°C 170°C third region 45°C testing. additional peak may indicate change material properties due degradation. SEM images showed phenomena similar vivo studies, varying severity depending radius. Thus, relevance for replication clinically relevant was demonstrated.