Method and apparatus for automatic shock electrode enabling

DETAILED DESCRIPTION Systems and methods useful for maximizing the likelihood of successful defibrillation or cardioversion using an automatic implantable cardioverter/defibrillator system are provided by the present invention.
The system is capable of monitoring the impedance of AICDs for purposes of detecting lead malfunctions.
After detection of a lead malfunction, the system of the present invention is capable of connecting or disconnecting leads and electrodes to maximize the likelihood of effective cardioversion and defibrillation.
These systems are fully implantable and do not require immediate invasive surgical techniques or frequent x-irradiation.
Various methodologies may be used to implement the present invention.
If a method is desired which can simply connect an electrode in response to a too-high impedance measurement, then the impedance of the AICD system is measured initially.
This may occur, for example, during a first shock phase.
The measured impedance then is compared to a high impedance threshold value.
If the measured impedance exceeds the threshold value, then at least one electrode is electrically connected to the system prior to the next shocking cycle.
Likewise, if a method is desired which can simply electrically disconnect an electrode in response to a too-low impedance measurement, then the impedance of the AICD system is initially measured, for example, during a first shock phase.
The measured impedance is then compared to a low impedance threshold.
Where the measured impedance drops below the lower threshold, at least one electrode is electrically disconnected from the system, as for example prior to the next shocking cycle.
A combined method for maximizing likelihood of successful defibrillation or cardioversion using an automatic implantable cardioverter/defibrillator system, will be preferred in certain instances.
Such a method will comprise a two-stage impedance comparison.
First, an impedance measurement of the system, as for example resulting from a first shock is taken