US Patent 7623916 Implantable cardiac stimulus devices and methods with input recharge circuitry

An illustrative embodiment includes an implantable cardiac stimulus device comprising input circuitry configured to reduce the time required to return to small signal operation after a disturbance of small signal operation. In another illustrative embodiment, the present invention includes methods for operating an implantable cardiac stimulus device to reduce the time required to return to small signal operation after a disturbance of small signal operation. In yet additional embodiments, the initiation of small signal operation after a change in sensing vector and/or after delivery of a stimulus to the patient is improved by the inclusion of input circuitry and/or the use of methods adapted to reduce the time needed to reach small signal operation.