Estella Pulse Generators - BIOTRONIK USA - News

60 Estella Pulse Generators Technical ManualTo prevent ventricular pulse inhibition in the presence of crosstalk,a ventricular pulse will be emitted at the end of the safety AV delay(Figure 12). When pacing is AV sequential at the pre-set safety AVdelay, the presence of crosstalk should be considered and appropriatereprogramming performed (lengthen the ventricular blanking time,lower ventricular sensitivity, bipolar configuration, and/or lower atrialpulse energy).Figure 11: Ventricular blanking time and safety AV delay (Dualchamber)7.5.8 Upper Rate and UTR ResponseThe upper rate is programmable (up to 200 ppm) for the dual chambersensing modes [DDD(R) and VDD(R)], and for all triggered modes (singleand dual chamber). The ventricular pacing rate will never exceed theprogrammed upper rate regardless of the patient’s atrial rate.7.6 Lead PolarityThe programmed lead polarity determines whether the pulse generatorsenses or paces in a unipolar or bipolar configuration. Lead polarity canbe programmed separately for sensing and pacing in both chambers.If a bipolar lead is connected to the pulse generator, unipolar or bipolarconfiguration can be programmed for pacing and sensing. As comparedto bipolar pacing, the unipolar pacing pulse has the advantage of beingclearly identifiable on the ECG. Unipolar pacing occasionally results inmuscle stimulation in the pulse generator pocket or diaphragm.Bipolar sensing offers an improved “signal-to-noise” ratio due tothe decreased susceptibility to interference signals like skeletalmyopotentials or EMI, and, therefore, permits programming of highersensitivities (lower values).