A longevity calculation was completed and it was confirmed that the device did not meet longevity expectations.Device memory was reviewed and no faults or errors were noted.It was confirmed that the device was in ddd mode at the time the replacement indicator was declared.It was also noted that the device sensed in the atrial chamber 100 percent of the time while implanted with prolonged high atrial rates.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.Chronic high atrial rates, as occurred with this device, can reduce longevity in devices that are programmed ddd(r) with atrial sensing on.Device power consumption increases proportional to the additional processing for sensed atrial events.As a result, the high rate of atrial sensing was determined to be the cause of the longevity being lower than expected.
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