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.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 inappropriate treatment.Download fault flags were identified, but downloading is a secondary function of the device and does not interfere with the device's ability to detect and treat a patient.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 into 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 (b)(6) full energy (b)(4) biphasic pulses.The functional testing confirmed proper response button functionality, ecg acquisition, detection algorithm performance, and pulse delivery functionality of the device.Device manufacture date: monitor: sn (b)(4): 01/29/2015 reuse; electrode belt: sn (b)(4): 04/01/2014 reuse.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 improper response button use (patient pressed response buttons earlier in detection sequence but not prior to shock).The ecg analysis, conducted by trained ecg technicians, identified the primary cause of the false detection was svt rate over the treatment threshold.The rapid rate satisfied the rate detector of the detection algorithm.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.(b)(4).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.(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.The patient was at a rehabilitation center, conscious, and feeling dizzy at the time of the event.Patient's wife and a nurse were present at the time of the event.Supraventricular tachycardia (svt) rate above treatment threshold contributed to the false detection.The response buttons were pressed earlier in the detection sequence but not prior to the shock.The response buttons functioned appropriately.An ambulance was called and patient was transported to the hospital.Patient continued to wear the lifevest.
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