It was reported that the patient with this device presented in an atrial tachycardia which resulted in a ventricular tachycardia (vt).The vt rate was successfully treated by the device however, post shock delivery the physician questioned appropriate device detection as some pacing inhibition was observed at around 2 seconds of asystole the final treated episode exhibited undersensing which continued until the next untreated episode, approximately four minutes later.The patient was declared a cerebral death following a prolonged cardiac arrest which was secondary to severe ventricular arrhythmia on underlying congenital cardiomyopathy.The patient was later allowed to pass away following organ preservation for donation purposes.The device has also been removed and is expected to be returned for general post mortem analysis, along with an episode data review.
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It was reported that the patient with this device presented in an atrial tachycardia which resulted in a ventricular tachycardia (vt).The vt rate was successfully treated by the device however, post shock delivery the physician questioned appropriate device detection as some pacing inhibition was observed at around 2 seconds of asystole the final treated episode exhibited undersensing which continued until the next untreated episode, approximately four minutes later.The patient was declared a cerebral death following a prolonged cardiac arrest which was secondary to severe ventricular arrhythmia on underlying congenital cardiomyopathy.The patient was later allowed to pass away following organ preservation for donation purposes.The device has also been removed and returned for general post mortem analysis, along with an episode data review.
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The initial data evaluation from technical services confirmed that the 2.25 second pause in pacing post shock and brief undersensing noted in the ventricular episodes, was determined to be normal device behavior based on programmed parameters and the patients arrhythmia characteristics.This 2.25 second interval occurred immediately after the shock was delivered and is normal device operation to allow adequate time for intrinsic heart activity to resume before the device determines the appropriate response.Following this 2.25 second interval, there was no intrinsic atrial or ventricular activity and therefore, the device began to atrial and biventricular pace as designed.In both ventricular episodes there was evidence of brief rv undersensing due to the patients small and variable intrinsic r wave amplitudes, which resulted in some of the rv signals falling below the devices sensing threshold.However, it was determined that the devices therapy decisions were appropriate based on device programming and the patients variable intrinsic rv rate not remaining consistently above the lowest programmed zone of 180 bpm.With the available information, there is no indication of a device malfunction or that the device caused or contributed to the patients death.The physical device was subsequently returned for analysis.The returned device was thoroughly inspected and analyzed upon receipt at our post market quality assurance laboratory.Memory review noted no suspicious fault codes or resets.Visual examination of the device header and case noted no anomalies.The device was then exposed to simulated heart load conditions, and the defibrillation, 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 were also performed, and again, normal device function was observed.Analysis found no evidence of device defect, malfunction or damage outside the bounds of normal medical use.Based on returned product analysis and a review of the device history, we have concluded that device performance was not a cause or contributor to the outcome of this case.
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