MAUDE Adverse Event Report: BOSTON SCIENTIFIC CORPORATION ENDOTAK RELIANCE G; IMPLANTABLE LEAD

Model Number	0187
Medical Device Problem Code	High impedance (1291)
Health Effect - Clinical Codes	Electric Shock (2554); Shock from Patient Lead(s) (3162); No Clinical Signs, Symptoms or Conditions (4582)
Date of Event	11/10/2022
Type of Reportable Event	Serious Injury
Event or Problem Description
It was reported that during the non boston scientific device explant procedure, this right ventricular (rv) lead was found exhibiting high shock impedances out of range.Technical services (ts) recommended to perform a defibrillation threshold (dft) test, nonetheless, the physician decided to not perform it.A new implantable cardioverter defibrillator (icd) was implanted and connected to this rv lead.The rv lead remains in service and no adverse patient effects were reported.
Event or Problem Description
It was reported that during the non boston scientific device explant procedure, this right ventricular (rv) lead was found exhibiting high shock impedances out of range.Technical services (ts) recommended to perform a defibrillation threshold (dft) test, nonetheless, the physician decided to not perform it.A new implantable cardioverter defibrillator (icd) was implanted and connected to this rv lead.Furthermore, the patient was seen in the clinic and a dft was performed.The high shock impedances out of range were confirmed.The rv lead remains in service and no additional adverse patient effects were reported.
Event or Problem Description
It was reported that during the non boston scientific device explant procedure, this right ventricular (rv) lead was found exhibiting high shock impedances out of range.Technical services (ts) recommended to perform a defibrillation threshold (dft) test, nonetheless, the physician decided to not perform it.A new implantable cardioverter defibrillator (icd) was implanted and connected to this rv lead.Furthermore, the patient was seen in the clinic and a dft was performed.The high shock impedances out of range were confirmed.The rv lead remains in service and no additional adverse patient effects were reported.Additional information was received which indicated that, the shock lead impedance was gradually increased.This rv lead remains in service.No additional adverse patient effects were reported.
Additional Manufacturer Narrative
Investigation summary: with the available information, boston scientific determined that this lead exhibited a gradual rise in low-voltage shock impedance (lvsi) measurements.This observation may be consistent with calcification of the defibrillation coil(s), however can only be confirmed if the lead is returned for analysis.The calcification phenomenon may have contributed to the reported clinical observations.Device history record review: a review of the device history record (dhr) was performed.The review of the dhr identified that there were no process related non-conformances, scrap, or rework performed during the production that could explain the event.The reviews ensure each device meets specification prior to release for use.There is no indication the device manufacturing process contributed to the reported complaint.Device technical analysis: this product has not been returned to boston scientific and physical analysis could not be conducted.Investigation of the available information/data determined that the observed gradual rise in lvsi measurements was likely associated with calcification, as there was no conclusive evidence of compromised physical or electrical integrity of the lead.This condition may develop over time and can be reflected in a gradual and sustained increase in shock impedance measurements.Boston scientific issued a field safety notice to physicians in july 2025 regarding the potential for reliance defibrillation leads with expanded polytetrafluoroethylene (eptfe) coating to exhibit a pattern of gradually increasing lvsi measurements due to calcification, which may result in elevated high-voltage shock impedance (hvsi) measurements and reduced shock efficacy.Device labeling review: review of labeling determined that the complaint situation was listed in the manual.There was no indication in the complaint that the product was not used in accordance to labeling.The manual was unlikely to be the cause of the reported complaint; translation, wording, or graphics does not require further review.Investigation conclusion: cause traced to cause traced to device design.Gradually increasing lvsi measurements for leads with eptfe coating are suspected to be the result of encapsulation of the lead coil(s) due to calcification.Boston scientific issued a field safety notice to physicians in july 2025 regarding the potential for reliance defibrillation leads with eptfe coating to exhibit this phenomenon.Risk review: risk review is not required - the event is not reportable in an eea/great britain country + bsc is not responsible for training + no new hazard was identified.
Event or Problem Description
It was reported that during the non boston scientific device explant procedure, this right ventricular (rv) lead was found exhibiting high shock impedances out of range.Technical services (ts) recommended to perform a defibrillation threshold (dft) test, nonetheless, the physician decided to not perform it.A new implantable cardioverter defibrillator (icd) was implanted and connected to this rv lead.Furthermore, the patient was seen in the clinic and a dft was performed.The high shock impedances out of range were confirmed.The rv lead remains in service and no additional adverse patient effects were reported.Additional information was received which indicated that, the shock lead impedance was gradually increased.This rv lead remains in service.No additional adverse patient effects were reported.

• Brand Name: ENDOTAK RELIANCE G
• Common Device Name: IMPLANTABLE LEAD
• Manufacturer (Section D): BOSTON SCIENTIFIC CORPORATION; 4100 hamline avenue north; saint paul MN 55112
• Manufacturer (Section G): CPI - DEL CARIBE; guidant puerto rico b. v.; #12, rd. #698; dorado PR 00646
• Manufacturer Contact: timothy degroot ; 4100 hamline avenue north; saint paul, MN 55112 ; 6515826168
• MDR Report Key: 15839527
• Report Number: 2124215-2022-48346
• Device Sequence Number: 5717105
• Product Code: LWS
• UDI-Device Identifier: 00802526531217
• UDI-Public: 00802526531217
• Combination Product (Y/N): Y
• Initial Reporter State: MA
• Initial Reporter Country: US
• PMA/510(K) Number: P910073/S043
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Device Implanted Year: 2006
• Serviced by Third Party (Y/N): Unknown
• Reporter Type: Manufacturer
• Report Source: Company Representative
• Initial Reporter Occupation: Physician
• Type of Report: Initial,Followup,Followup,Followup
• Report Date (Section B): 04/17/2026

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Operator of Device: Lay User/Patient
• Device Expiration Date: 11/18/2006
• Device Model Number: 0187
• Device Catalogue Number: 0187
• Was Device Available for Evaluation?: No
• Is the Reporter a Health Professional?: Yes
• Type of Report(Section G): Follow-Up
• Initial Date Received by Manufacturer: 11/10/2022
• Supplement Date Received by Manufacturer: 12/22/2022; 02/05/2026; 04/15/2026
• Initial Report FDA Received Date: 11/21/2022
• Supplement Report FDA Received Date: 01/06/2023; 02/09/2026; 04/17/2026
• Was Device Evaluated by Manufacturer? (Y/N): Device Not Returned to Manufacturer
• Date Device Manufactured: 11/18/2004
• Is the Device Labeled for Single Use? (Y/N): Yes
• Is This a Single-Use Device that was Reprocessed and Reused on a Patient? (Y/N): No
• Usage of Device: Initial
• Patient Sequence Number: 1
• Outcome Attributed to Adverse Event: Required Intervention; Hospitalization
• Patient Age: 61 YR
• Patient Sex: Male