There was no death or device malfunction associated with the inappropriate defibrillation event.Device evaluation summary: monitor sn (b)(4) and electrode belt sn (b)(4) were returned and evaluated at the distributor, in accordance with procedures recommended by zoll manufacturing corporation.At this time the physical evaluation of the device at zmc does not add further value in the root-cause investigation of this complaint because the information contained in the distributor incident file, the qualified clinical consultant review, and/or the device download data suffices the root cause investigation of this event.The evaluation included review of downloaded software flag files on the day of the event and incoming functional testing.The review of the software flags consisted of an analysis of the downloaded data to identify any fault flags or unusual patterns of software flags.The software flag files did not suggest a device malfunction that would contribute to the patient treatment.During the incoming functional testing, a 1hz simulated normal sinus rhythm signal was applied to the ecg electrodes, followed by a 5hz simulated treatable arrhythmia signal which verified proper performance of the detection algorithm.During the transition to the 5hz signal, the device was confirmed to properly enter a treatment sequence which includes a verification of the tactile vibration alarm, audio messaging, and siren alarms, as well as a test of the pulse delivery circuitry.The pulse delivery circuitry test verified proper charging of the high voltage capacitors and proper delivery of five full energy 150j biphasic pulses.The functional testing confirmed proper response button functionality, ecg acquisition, detection algorithm performance, and pulse delivery functionality.Manufacture date: monitor - (b)(4) -06/08/2020, belt - (b)(4) -05/06/2016.The investigation into the event concludes that there was no device malfunction.A cause and effect analysis was conducted using all of the available information which includes the incident report, device evaluation, software flag files, and ecg strips.The primary cause of the inappropriate shock was lack of response button use by the patient during the false detection.The ecg analysis, conducted by trained ecg technicians, identified the primary cause of the false detection was oversensing of low-amplitude cardiac signal.Inappropriate defibrillations are an anticipated risk associated with the use of the lifevest.Patients are instructed through alarms, voice messages, ifu, and training to press the response buttons to prevent an inappropriate defibrillation.The current commercial inappropriate defibrillation rate is consistent with the observed rate during the pivotal clinical trial (b)(4) (0.69% per patient-month with 90% confidence).A summary of the safety and effectiveness data (ssed), including the inappropriate defibrillation safety objective supporting fda's approval of the lifevest, can be found at (http://www.Accessdata.Fda.Gov/cdrh_docs/pdf/p010030b.Pdf).The lifevest detection algorithm complies with iec 60601-2-4 performance requirements for sensitivity and specificity.Inappropriate treatment events are assessed during the monthly data analysis of complaints per (b)(4).
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A us distributor contacted zoll to report that a patient experienced an inappropriate defibrillation event consisting of one shock.It was reported that the patient was in a medical center, conscious, and feeling well at the time of the treatment delivery.The response buttons were not pressed during the event.Oversensing of low-amplitude cardiac signal contributed to the false detection.The patient received continued medical attention at the medical center and continues to wear the lifevest.There was no death or device malfunction associated with the inappropriate defibrillation event.
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