| 摘要 |
Apparatus and technique for compensating the potential detected by amplifier circuits for sensing cardiac activity in an active implantable medical device, such as in a pacemaker, defibrillator, cardioverter and multisite device. This device includes circuits for delivering to a cardiac cavity stimulation pulses of predetermined voltage levels and pulse widths, and circuits for sensing cardiac activity comprising an amplifier of signals sensed by an intracardiac electrode, delivering at its output a value of measured potential (Pmeasured) consecutive with the application of a stimulation pulse (I). The device includes circuits for determining a response potential specific to that amplifier, independently of the presence or absence of a myocardial depolarization. Advantageously, the device extracts from the value of measured potential (Pmeasured) consecutive to the delivery of the stimulation pulse (I), the value of the specific response potential (Pampli) from the amplifier corresponding to the pulse width (Ls) and the voltage level (Vs) of the aforementioned stimulation pulse. Knowing the specific response potential allows the device to identify more reliably when the measured potential (Pmeasure) corresponds to a myocardial depolarization (Pstim).
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