An Integrated Dual Sensor System Automatically Optimized by Target Rate Histogram

The use of combined sensors and advanced algorithms using different principles can improve rate performance over a single sensor system. Combinations of sensors and more sophisticated algorithms, however, invariably increase the complexity of pacemaker programming. An automatically optimized combined minute ventilation and activity DDDR pacemaker was developed to minimize repeated sensor adjustment. The device used subthreshold (below cardiac stimulation threshold) lead impedance to detect lead configuration at implantation automatically, followed by “implant management,” including setting of lead polarity and initiation of DDDR pacing. Automatic sensor adaptation was achieved by programming a “target rate histogram” based on the patient's activity level and frequency of exertion, and the rate profile optimization process matched the recorded integrated sensor response to the target rate histogram profile. In nine patients implanted with the DX2 pacemakers, the implant management gave 100% accuracy in the detection of lead polarity. Rate profile optinuzation automatically increased the pacing rate during exercise between discharge and 3-month follow-up (hall walk: 78 ± 3 vs 98 ± 3 beats/min, and maximal treadmill exercise: 89 ± 6 vs 115 ± 5 beats/min, P < 0.001) with a significant increase in exercise duration during maximal exercise (7.18 ± 1 min vs 9.56 ± 2 min, P = 0.05). The accuracy of rate profile optimization versus manual programming was assessed at 1 month, and there was no significant difference between pacing rate kinetics and maximal pacing rate between the two methods of programming. In conclusion, pacemaker automaticity can be initiated at implantation and the self-optimized rate adaptive response appeared to be comparable to that derived from a manual programming procedure, which may reduce the need to perform time consuming sensor programming.