MAUDE Adverse Event Report: BOSTON SCIENTIFIC CORPORATION DYNAGEN X4 CRT-D; DEFIBRILLATOR, AUTOMATIC IMPLANTABLE CARDIOVERTER, WITH CRT-D

Model Number	G156
Medical Device Problem Codes	Signal Artifact/Noise (1036); High impedance (1291); Over-Sensing (1438); Pacing Problem (1439); Inappropriate/Inadequate Shock/Stimulation (1574); Failure to Read Input Signal (1581)
Health Effect - Clinical Code	No Clinical Signs, Symptoms or Conditions (4582)
Date of Event	09/21/2025
Type of Reportable Event	Serious Injury
Event or Problem Description
It was reported that this cardiac resynchronization therapy defibrillator (crt-d) system, implanted with a non-boston scientific right ventricular (rv) lead, exhibited consistently high, out-of-range pace impedance measurements greater than 3,000 ohms and low r-waves.This nearly 300 episodes were stored starting in september 10 with noise and significant oversensing, three bursts of inappropriate anti-tachycardia pacing (atp), and 23 inappropriate shocks.Therapy was not exhausted, and normal sinus rhythm was observed after each shock.Technical services (ts) discussed troubleshooting options and possible causes, such as lead fracture.There was approximately 11 months remaining on the battery, and the lead revision may be considered at the upcoming device changeout.This crt-d system remains in service.No interventions or additional adverse patient effects were reported at this time.
Additional Manufacturer Narrative
The local area field representative was contacted for additional information regarding event cause and resolution.At this time, no further information is available.Should additional information become available this report will be updated.
Additional Manufacturer Narrative
If pertinent information is provided in the future, a supplemental report will be submitted.Correction to e1: correction to initial reporter's name.
Event or Problem Description
It was reported that this cardiac resynchronization therapy defibrillator (crt-d) system, implanted with a non boston scientific right ventricular (rv) lead, exhibited consistently high, out-of-range pace impedance measurements greater than 3,000 ohms and low r-waves.This nearly 300 episodes were stored starting in september 10 with noise and significant oversensing, three bursts of inappropriate anti-tachycardia pacing (atp), and 23 inappropriate shocks.Therapy was not exhausted, and normal sinus rhythm was observed after each shock.Technical services (ts) discussed troubleshooting options and possible causes, such as lead fracture.There was approximately 11 months remaining on the battery, and the lead revision may be considered at the upcoming device changeout.This crt-d system remains in service.No interventions or additional adverse patient effects were reported at this time.Additional information received reported that this crt-d was explanted and replaced due to normal battery depletion (nbd).At the routine device changeout, the non boston scientific rv lead was surgically abandoned and replaced.No adverse patient effects were reported.The crt-d was returned for analysis.
Event or Problem Description
It was reported that this cardiac resynchronization therapy defibrillator (crt-d) system, implanted with a non boston scientific right ventricular (rv) lead, exhibited consistently high, out-of-range pace impedance measurements greater than 3,000 ohms and low r-waves.This nearly 300 episodes were stored starting in september 10 with noise and significant oversensing, three bursts of inappropriate anti-tachycardia pacing (atp), and 23 inappropriate shocks.Therapy was not exhausted, and normal sinus rhythm was observed after each shock.Technical services (ts) discussed troubleshooting options and possible causes, such as lead fracture.There was approximately 11 months remaining on the battery, and the lead revision may be considered at the upcoming device changeout.This crt-d system remains in service.No interventions or additional adverse patient effects were reported at this time.Additional information received reported that this crt-d was explanted and replaced due to normal battery depletion (nbd).At the routine device changeout, the non boston scientific rv lead was surgically abandoned and replaced.No adverse patient effects were reported.The crt-d was returned for analysis.
Additional Manufacturer Narrative
If pertinent information is provided in the future, a supplemental report will be submitted.
Event or Problem Description
It was reported that this cardiac resynchronization therapy defibrillator (crt-d) system, implanted with a non-boston scientific right ventricular (rv) lead, exhibited consistently high, out-of-range pace impedance measurements greater than 3,000 ohms and low r-waves.This nearly 300 episodes were stored starting in september 10 with noise and significant oversensing, three bursts of inappropriate anti-tachycardia pacing (atp), and 23 inappropriate shocks.Therapy was not exhausted, and normal sinus rhythm was observed after each shock.Technical services (ts) discussed troubleshooting options and possible causes, such as lead fracture.There was approximately 11 months remaining on the battery, and the lead revision may be considered at the upcoming device changeout.This crt-d system remains in service.No interventions or additional adverse patient effects were reported at this time.Additional information received reported that this crt-d was explanted and replaced due to normal battery depletion (nbd).At the routine device changeout, the non-boston scientific rv lead was surgically abandoned and replaced.No adverse patient effects were reported.The crt-d was returned for analysis.
Additional Manufacturer Narrative
Correction to e1: correction to initial reporter's name.The returned device was thoroughly inspected and analyzed upon receipt at our post market quality assurance laboratory.Pin gage testing, designed to verify proper port dimensions, was completed.Each port measured as expected.The device was then exposed to simulated heart load conditions, and the pacing, and sensing functions were tested.Impedance testing was completed, and all measurements were within normal limits.The device operated appropriately with no interruptions in therapy output at the returned programmed settings.A series of electrical tests was also performed, and again, normal device function was observed.Analysis did not identify any device characteristics that would have caused or contributed to the reported clinical observations.The associated investigation also determined that this device exhibited intermittent changes in impedance measurements with no conclusive evidence of a product performance issue or inadequate lead-to-device connection.Engineering analysis and testing of returned products has determined that repeated, small movements of the lead terminal ring along with variances in the connection contact force and surface roughness can impact the connection between the spring contact and the lead ring, resulting in intermittent changes in impedance measurement.

• Brand Name: DYNAGEN X4 CRT-D
• Common Device Name: DEFIBRILLATOR, AUTOMATIC IMPLANTABLE CARDIOVERTER, WITH CRT-D
• Manufacturer (Section D): BOSTON SCIENTIFIC CORPORATION; 4100 hamline avenue north; saint paul MN 55112
• Manufacturer (Section G): BOSTON SCIENTIFIC CORPORATION; cashel road; clonmel ; EI
• Manufacturer Contact: timothy degroot ; 4100 hamline avenue north; saint paul, MN 55112 ; 6515826168
• MDR Report Key: 23344350
• Report Number: 2124215-2025-74914
• Device Sequence Number: 21218505
• Product Code: NIK
• UDI-Device Identifier: 00802526534669
• UDI-Public: (01)00802526534669(17)200115
• Combination Product (Y/N): N
• Initial Reporter State: AZ
• Initial Reporter Country: US
• PMA/510(K) Number: P010012
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Device Implanted Year: 2020
• Device Explanted Year: 2025
• Serviced by Third Party (Y/N): Unknown
• Reporter Type: Manufacturer
• Report Source: Health Professional
• Initial Reporter Occupation: Physician
• Type of Report: Initial,Followup,Followup,Followup
• Report Date (Section B): 01/14/2026

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: 01/15/2020
• Device Model Number: G156
• Device Catalogue Number: G156
• Device Lot Number: 379265
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Is the Reporter a Health Professional?: Yes
• Type of Report(Section G): Thirty-Day
• Initial Date Received by Manufacturer: 09/23/2025
• Supplement Date Received by Manufacturer: 10/17/2025; 10/17/2025; 12/31/2025
• Initial Report FDA Received Date: 10/20/2025
• Supplement Report FDA Received Date: 10/31/2025; 10/31/2025; 01/14/2026
• Was Device Evaluated by Manufacturer? (Y/N): Yes
• Date Device Manufactured: 03/10/2018
• 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: Other
• Patient Age: 76 YR
• Patient Sex: Female