The explanted lead was returned to the manufacturer on 08/20/2015 for analysis.Product analysis results confirmed discontinuity of both positive and negative quadfilar coils in the body region of the returned lead portions; also observed abraded openings of both the outer and inner tubing near the break location.During the visual analysis of the returned 316mm portion, the end of the (-) connector pin quadfilar coil appeared to be broken approximately 265mm and the end of the (+) connector ring quadfilar coil appeared to be broken at approximately 266mm from the end of the connector boot.Scanning electron microscopy was performed on the (-) connector pin quadfilar coil break (found at 265mm) and identified the area as having extensive pitting which prevented identification of the coil fracture type.Scanning electron microscopy was performed on the (+) connector ring quadfilar coil break (found at 266mm) and identified the area on two of the broken coil strands as being mechanically damaged (smooth surfaces) which prevented identification of the coil fracture type.The area on the third broken coil strand was identified as having extensive pitting which prevented identification of the coil fracture type.The area on the remaining broken coil strand was identified as having evidence of a stress induced fracture (fatigue appearance) with mechanical damage and evidence of a stress induced fracture (rotational forces) which most likely completed the fracture and no pitting.Pitting was observed on the coil surface.During the visual analysis of the returned 84mm portion quadfilar coil 1 appeared to be broken approximately 2mm and quadfilar coil 2 appeared to be broken at approximately 4mm from the end of the abraded open / outer / inner silicone tubes.Scanning electron microscopy was performed on the quadfilar coil 1 coil break (found at 2mm) and identified the area on two of the broken coil strands as having evidence of a stress induced fracture (fatigue appearance) with mechanical damage and no pitting.The two remaining broken coil strands were identified as having evidence of a stress induced fracture (rotational forces) which most likely completed the fracture and no pitting.Scanning electron microscopy was performed on the quadfilar coil 2 coil break (found at 4mm) and identified the area on three of the broken coil strands as having evidence of a stress induced fracture (fatigue appearance), mechanical damage and evidence of a stress induced fracture (rotational forces) which most likely completed the fracture on two of these broken coil strands.The area on the fourth broken coil strand was identified as being mechanically damaged (smooth surfaces) which prevented identification of the coil fracture type and no pitting.It is believed that stimulation was present for a certain period of time as evidenced by the presence of metal pitting.Low magnification sem analysis of the quadfilar coil shows characteristics typical of a lead discontinuity which may include: material fracture, rough or pitted surface, thinned material thickness, electro-etching or material dissolution.The abraded openings and incision mark found on the outer silicone tubing, most likely provided the leakage path for the dried remnants of what appeared to have once been body fluids found inside the outer silicone tubing.The abraded openings found on the inner silicone tubes, most likely provided the leakage path for the dried remnants of what appeared to have once been body fluids found inside the inner silicone tubes.With the exception of the observed discontinuities and the abraded inner tubing, the condition of the returned lead portions is consistent with conditions that typically exist following an explant procedure.No other obvious anomalies were noted.The setscrew marks found on the lead connector pin provide evidence that, at one point in time, a good mechanical and electrical connection was present.Continuity checks of the returned lead portions were performed, during the visual analysis, and no other discontinuities were identified.
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