MAUDE Adverse Event Report: ELEMENT SCIENCE, INC. JEWEL; WEARABLE CARDIOVERTER DEFIBRILLATOR (WCD)

Model Number	ES-2
Medical Device Problem Code	Human-Device Interface Problem (2949)
Health Effect - Clinical Code	No Clinical Signs, Symptoms or Conditions (4582)
Date of Event	03/16/2026
Type of Reportable Event	Serious Injury
Additional Manufacturer Narrative
The device was returned to the manufacturer and detailed investigation was performed.The device successfully passed all functional tests.Review of the device system log confirmed that the patient had previously and successfully deferred alarms.During the reported event, the system log shows the patient attempted to cancel the shock but did not actuate both buttons simultaneously for the extent required to trigger deferral.Based on the totality of the investigation findings, including functional tests and system log data, the device did not malfunction.
Event or Problem Description
The patient's doctor notified element science territory manager on (b)(6), 2026, that the patient had received a shock and went to the er.It is reported at the time of the event, patient was walking back from the restroom early in the morning.They heard the jewel alarm and audible notification that the device was preparing to deliver a shock.They were unable to defer and received a shock.The patient went to the er and it was reported there was no patient injury.Patient was observed overnight and then released from er.

• Brand Name: JEWEL
• Common Device Name: WEARABLE CARDIOVERTER DEFIBRILLATOR (WCD)
• Manufacturer (Section D): ELEMENT SCIENCE, INC.; 301 chesapeake dr.; redwood city CA 94063
• Manufacturer (Section G): ELEMENT SCIENCE, INC.; 301 chesapeake dr.; redwood city CA 94063
• Manufacturer Contact: vis ayer ; 301 chesapeake dr; redwood city, CA 94063 ; 4158726500
• MDR Report Key: 24878095
• Report Number: 3027605722-2026-00001
• Device Sequence Number: 18611489
• Product Code: MVK
• UDI-Device Identifier: 00850047782007
• UDI-Public: 00850047782007
• Combination Product (Y/N): N
• Initial Reporter State: TX
• Initial Reporter Country: US
• PMA/510(K) Number: P230022
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Serviced by Third Party (Y/N): N
• Reporter Type: Manufacturer
• Report Source: Health Professional
• Initial Reporter Occupation: Physician
• Type of Report: Initial
• Report Date (Section B): 03/16/2026

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?: No
• Operator of Device: Lay User/Patient
• Device Expiration Date: 02/28/2026
• Device Model Number: ES-2
• Device Catalogue Number: JWL-1-MDU0-E01
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 03/16/2026
• Is the Reporter a Health Professional?: Yes
• Type of Report(Section G): Thirty-Day
• Initial Date Received by Manufacturer: 03/16/2026
• Initial Report FDA Received Date: 04/14/2026
• Was Device Evaluated by Manufacturer? (Y/N): Yes
• Date Device Manufactured: 10/03/2025
• Is the Device Labeled for Single Use? (Y/N): No
• 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: Hospitalization
• Patient Age: 84 YR
• Patient Sex: Female
• Patient Weight: 94 KG