Abstract: Polarization signals, which represent voltages measured at a pacemaker electrode, are not constant and may drift. Polarization signal drift, which often precedes undesirable pace polarization artifacts, is more significant when the pacemaker is inhibited from providing an electrical stimulation to the patient's heart. The present invention provides an implantable system and methods for stabilization of a polarization signal. Electrical pulses may be applied to stabilize a polarization signal. In one implementation of the invention, polarization signal stabilization may be used as part of process to terminate tachycardia.

Abstract: Polarization signals, which represent voltages measured at a pacemaker electrode, are not constant and may drift. Polarization signal drift, which often precedes undesirable pace polarization artifacts, is more significant when the pacemaker is inhibited from providing an electrical stimulation to the patient's heart. The present invention provides an implantable system and methods for stabilization of a polarization signal. Electrical pulses may be applied to stabilize a polarization signal. In one implementation of the invention, polarization signal stabilization may be used as part of process to terminate tachycardia.

Abstract: Polarization signals, which represent voltages measured at a pacemaker electrode, are not constant and may drift. Polarization signal drift, which often precedes undesirable pace polarization artifacts, is more significant when the pacemaker is inhibited from providing an electrical stimulation to the patient's heart. The present invention provides an implantable system and methods for stabilization of a polarization signal. Electrical pulses may be applied to stabilize a polarization signal. In one implementation of the invention, polarization signal stabilization may be used as part of process to terminate tachycardia.

Abstract: A method of discriminating a captured beat is provided. A pulse is transmitted and an evoked response signal is received. The evoked response signal is filtered and the filtered response signal is analyzed for at least one positive signal component. Systems and devices for discriminating a captured beat are also provided.

Abstract: A method of discriminating a captured beat is provided. A pulse is transmitted and an evoked response signal is received. The evoked response signal is filtered and the filtered response signal is analyzed for at least one positive signal component. Systems and devices for discriminating a captured beat are also provided.

Abstract: There is provided a pacemaker system with capture verification and threshold testing, in which the pacemaker adjusts the post-stim pulse portion of a triphasic pulse to minimize polarization, and waits after each change in delivered pace pulses for a stabilization interval, in order to enhance capture verification. The threshold test utilizes a pace pulse pair, comprising a prior search pulse which is varied during the test, and the regular pacing pulse which is above threshold. When delivery of the pulse pairs is initiated, the search pulse is adjusted to optimize polarization, and the pacemaker waits for a predetermined stabilization period of time in order to allow for minimum polarization and to optimize capture detection. The search pulse is increased incrementally in output value toward threshold, and following each such increase the pacemaker waits for a stabilization interval. The pacemaker detects when capture is achieved by the search pulse, thereby providing an indication of threshold.

Abstract: There is provided an output stage for a battery powered implantable device, such as a cardiac pacemaker, for generating biphasic or triphasic pulses, each pulse having at least a prestimulus or poststimulus pulse of a first polarity, and a stimulus pulse of opposite polarity. The output stage provides for charging of a small sized pacing capacitor from the battery through a high rate charge pump only during delivery of a prestim or poststim pulse, and for discharging the pacing capacitor during the stimulus portion of the overall pulse. A fast or high rate capacitive charge pump is used with a controllable high rate clock signal, adjustment of the clock signal being used for controlling the charging rate during the prestim or poststim pulses, thereby allowing for tuning of the parameters of the prestim or poststim pulse portions.

Abstract: There is provided a pacemaker having automatic adjustment of the sensitivity for sensing cardiac signals such as QRS, T and P waves. The pacemaker has software for examining each inputted signal, obtaining a measure of the peak amplitude, e.g. one-half, comparing such measure with a stored software sensitivity level, and adjusting the software sensitivity level each beat so that it effectively tracks beat-to-beat changes in the signal amplitude. The adjusted software sensitivity level is used for determining when an input signal is to be accepted as a true signal, or rejected.

Abstract: There is provided a pacemaker system with capture verification and threshold testing, in which the pacemaker waits after each change in delivered pace pulses for a stabilization interval, in order to minimize polarization and enhance capture verification. The threshold test utilizes a pace pulse pair, comprising a prior search pulse which is varied during the test, and the regular pacing pulse which is above threshold. When delivery of the pulse pairs is initiated, the search pulse is adjusted to optimize polarization, and the pacemaker waits for predetermined stabilization period of time in order to allow for minimum polarization and to optimize capture detection. The search pulse is increased incrementally in output value toward threshold, and following each such increase the pacemaker waits for a stabilization interval. The pacemaker detects when capture is achieved by the search pulse, thereby providing an indication of threshold.