Apparatus and method for detection of lead failure in an implantable medical device

摘要

A method for automatic threshold control and detection of lead failure in an implanted medical device obtains three sensing vectors for measurement of an electrocardiogram signal. A dynamic error signal is determined from the vectors, and may be used to set a detection threshold for insufficient ECG signals, and/or to passively monitor the device for indications of lead failure without performing an impedance measurement. Passive mode operation conserves battery power and enables continuous lead integrity checks. A quality factor may also be determined from the error signal, to indicate whether or not signal measurements are valid with respect to noise levels. If the detection threshold is allowed to decay between successive features of the electrocardiogram, the decay rate may be made adaptive such that it automatically adjusts to changes in heart rate or to changes in amplitude of the electrocardiogram features.

主权项

1. A method of determining electrocardiogram (ECG) signal quality in an implantable medical device (IMD), the method including the steps of:
a. sensing at least three ECG signals from at least three spaced electrodes; b. calculating at least three sensing vectors from the ECG signals, each vector representing the difference between ECG signals from a pair of the spaced electrodes, wherein each vector is obtained from a different one of the pairs of electrodes; c. calculating a dynamic error signal from the vectors, the dynamic error signal being dependent on the difference between:
(1) one of the vectors, and(2) the sum of the other vectors; and d. adapting the sensing of the ECG signals in dependence on the dynamic error signal.