Patent ID: 6836682
Filing Date: 2004-12-28
Classification: A61N

Abstract:
A rate responsive pacing system having a pacemaker device and a lead system interconnecting said device and a patient's heart, said device having a pulse generator for generating pacing pulses, sensing means for sensing cardiac signals connected from said pulse generator to deliver pacing pulses at said sensor rate, said sensor means comprising:algorithm means for calculating a measure of the T wave portion of a received intrinsic cardiac signal; comparing means for comparing said measure with a predetermined criterion to detect the occurrence of the T wave portion of said signal; data means for determining and storing intrinsic QT interval data and heart rate data for each received intrinsic signal for which a T wave has been detected; and reference means for setting a QT reference curve as a function of said stored intrinsic QT interval and rate data, wherein said sensor means comprises high rate limit means for setting a maximum sensor rate, and wherein said algorithm means, said comparing means and said state means are operative at rates above said maximum sensor rate.