Estella Pulse Generators - BIOTRONIK USA - News

112 Estella Pulse Generators Technical Manual12.3 Threshold TestThe pulse generator models are equipped with a high-precisionthreshold test with a resolution of 0.1 V ranging from 0.1 V to 7.5 V.The threshold test is activated as a temporary program whose specificoperation is defined by the applicable software version. The threshold isdetermined by observing the ECG or IEGM. Likewise, all determinationsof threshold or threshold margin, by any means, should only beperformed by use of temporary programming to permit immediatereactivation of the permanent program in case of loss of capture.Removal of the programmer head immediately stops the test andreactivates the permanent program.The threshold test should be performed with the pulse widthprogrammed to the same value as that selected for the permanentprogram. To ensure pacing, the pacing rate of the threshold test programshould exceed the patient’s intrinsic rate.To determine the threshold, the ECG or IEGM must be observedcontinuously. Based on the measured threshold, the pulse amplitudefor the permanent program should be adjusted. Please consult thepertinent medical literature for specific recommendations regardingnecessary safety margins.In addition to the manual ventricular threshold test, the thresholdtest can be performed automatically, requiring no user interaction.The automatic threshold test uses the VCC function to determine thethreshold. Once the threshold is determined, VCC is deactivated if thefeature is not programmed ON in the permanent program.12.4 P/R MeasurementThe pulse generators provide a P-/R-wave test for measuring theamplitude of intrinsic events during follow-up examination. The testdetermines the minimum, mean and maximum amplitude values over aprogrammable period of time. In addition, these values may be printedout.To permit evaluation of the sensing function, the pacing rate must belower than the patient’s intrinsic rate. In demand pacing, the propersensing function can be recognized if the interval between intrinsicevents and the following pacing pulse equals the basic interval (if noHysteresis is programmed).For evaluation of the sensing function, the pulse generator features anintracardiac electrogram (IEGM) with marker signals to indicate sensedand paced events. In addition, triggered pacing modes can be selected,which synchronously to the detection of an intrinsic event, emit a pacingpulse and mark the sensed event and its timing on the ECG.