Cardiac rhythm management system including nonlinear, non-blanking sense amplifier

摘要

A cardiac rhythm management system provides a nonlinear gain characteristic. The system operates without blanking switches that decouple its inputs from electrodes during delivery of a pacing or recharge pulse. The nonlinear gain characteristic includes piecewise linear and logarithmic gain characteristics. Signals having amplitudes that are smaller than an input threshold voltage are amplified by less than signals having amplitudes that exceed the input threshold voltage. Intrinsic heart activity signals are amplified. Detected pacing pulses are attenuated. The system is capable of detecting an evoked response to determine whether a pacing pulse resulted in a successful heart contraction. Autocapture techniques allow adjustment of the pacing pulse energy based on the evoked response.