AN INTEGRATED DUAL SENSOR SYSTEM AUTOMATICALLY OPTIMIZED BY TARGET RATE HISTOGRAM

The use of combined sensors and advanced algorithms using different pr inciples can improve rate performance over a single sensor system. Com binations of sensors and more sophisticated algorithms, however, invar iably increase the complexity of pacemaker programming. An automatical ly optimized combined minute ventilation and activity DDDR pacemaker w as developed to minimize repeated sensor adjustment. The device used s ubthreshold (below cardiac stimulation threshold) lead impedance to de tect lead configuration at implantation automatically, followed by ''i mplant management,'' including setting of lead polarity and initiation of DDDR pacing. Automatic sensor adaptation was achieved by programmi ng a ''target rate histogram '' based on the patient's activity level and frequency of exertion, and the rate profile optimization process m atched the recorded integrated sensor response to the target rate hist ogram profile. In nine patients implanted with the DX2 pacemakers, the implant management gave 100% accuracy in the detection of lead polari ty. Rate profile optimization 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 exe rcise duration during maximal exercise (7.18 +/- 2 min vs 9.56 +/- 2 m in, P = 0.05). The accuracy of rate profile optimization versus manual programming was assessed at I month, and there was no significant dif ference between pacing rate kinetics and maximal pacing rate between t he two methods of programming. In conclusion, pacemaker automaticity c an be initiated at implantation and the self-optimized rate adaptive r esponse appeared to be comparable to that derived from a manual progra mming procedure, which may reduce the need to perform time consuming s ensor programming.