CARDIOVERSION/DEFIBRILLATION LEAD IMPEDANCE MEASUREMENT SYSTEM

摘要

A lead integrity measurement system for a cardiacpacemaker/cardioverter/defibrillator (PCD) of the type comprising animplantablepulse generator (IPG) and a lead system including one or more pacing leadseach having a proximal end coupled to a pacing terminal ofthe IPG and a distal end with at least one pace/sense electrode in contactwith a patient's heart and a pair of defibrillation leads coupled todefibrillation terminals of the IPG and defibrillation electrodes implanted inrelation to the patient's heart. In a lead impedance test mode,the terminal of a selected defibrillation lead under test is coupled to systemground, and an excitation voltage is applied in an excitationpath from a force lead terminal selected from the pacing leads. A measure leadis selected from among the other of the pacing leads anddefibrillation leads, and the voltage induced in the lead under test ismeasured through the measure lead and the electrode/tissue interfaceof the measure lead and the defibrillation lead under test. The appliedcurrent in the excitation path is also measured, and an impedancevalue is derived from the measured current and voltage values. The test iscontinued with other selections of excitation and measure paths.Comparisons of the measured impedances with maximum and minimum impedancevalues are used to determine lead integrity failures.The lead impedance between two defibrillation leads is determined as afunction of the sum of the derived defibrillation lead impedances.