It was reported to a company representative that a surgeon reported a failure to detect a heart rate with a model 106 generator.The patient had a successful pre-screening.It was determined that a sensitivity of 1 was appropriate.During the implant, the surgeon tried all the sensitivity settings and could only get "????" and a brief heartrate detection.The rate displayed for a few brief seconds before the "????" appeared again.The device was not implanted.A second generator was used and the impedance upon diagnostics was indicated to be within normal limits.The generator has been received for analysis, which is underway, but has not been completed to-date.Additional relevant information has not been received to-date.
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Analysis was completed for the returned generator.The report of undersensing was duplicated in the lab.The pulse generator was placed in a final test fixture.The stimulus (waveform generator) and pulse generator were connected to an oscilloscope for visual confirmation of pulse generator sensing the stimulus.Heart beat sensitivity setting two (as received) was evaluated with a no load and 2k load conditions.The pulse generator's sensing response observed showed sense delay starts of 8.2 seconds with a no load condition and 6.0 seconds with a 2k load condition.A comprehensive automated electrical evaluation showed that the pulse generator performed according to functional specifications.The pulse generator was opened.Possible contaminates were observed on the trimmed edge of the printed circuit board assembly.The battery was removed.The pulse generator module was subjected to an electrical test.Results show that the pulse generator module failed several electrical tests; supply current 2ma/normal, supply current off, supply current off sense, trim diagon current.The pulse generator was instrumented in order to evaluate the delay in producing a heartbeat detection synch pulse.This synch pulse is received by the tablet and used to calculate the heartbeat rate.Test results of the synch pulse revealed a longer delay (from initiation of the hb detection algorithm until hb synch pulses occur) than what is expected.Remaining residual material on the printed circuit board assembly edge after the ¿test tab¿ removal during the manufacturing process may have been the contributing factor for the report of undersensing.Review of the downloaded data revealed no anomalies.
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