System for monitoring hermetic integrity, pacing pulse and load impedance in cardiac pacers

摘要

A complete system for telemetering and monitoring the functioning of an implanted pacemaker as well as controlling the testing of the functions from a remotely located central facility is disclosed specifically comprising the provision of capabilities for directly and simultaneously transmitting from the pacer, electrical signals indicative of multiple pacer functions such as pacer rate, cell voltage, refractory period, heart rate with pacer inhibited, R- wave level and sensing margin, sensing circuit and other component failure, cardiac electrode, lead break, and hermetic integrity. The indicative signals are picked up at the patient's location for local analysis and/or telephonically communicated to a remote central monitoring station. The central station may control testing of the pacemaker functions by transmitting command signals back telephonically for coupling through cooperating external and implanted inductances or mangetically controlled switches to the implanted pacer circuitry. Systems of particular value in pacers with single cell lithium iodide power sources are also provided for integrating pacer output pulse current and voltage and producing indicative signals which are telemetered to permit monitoring of cell and electrode pacing impedance. Additionally, provision is made for avoiding sensing of the electrode "after potential" and for differentiating the refractory signal to produce a marker pulse in the telemetered signal. Improvements in the telemetry oscillator are also disclosed.