Cardiac rhythm management system with painless defibrillation lead impedance measurement

摘要

A cardiac rhythm management system includes a defibrillation lead impedance measurement system by which defibrillation lead impedance is measured using a test current source different from the defibrillation output supply. A resulting voltage is measured to determine the defibrillation lead impedance. Using low amplitude test currents (e.g., 10-20 milliamperes) avoids patient discomfort. Charge-balanced test currents avoids charge build-up that may interfere with sensing and avoids electrode degeneration. Different current amplitudes and resulting measured voltages provide a differential defibrillation lead impedance measurement for canceling undesired effects. Bidirectional test currents account for polarity effects on the defibrillation lead impedance measurement. A calibration/correction technique uses measurements of known resistances to correct a measurement of an unknown defibrillation lead impedance measurement.