Abstract: An implantable device for the treatment of malfunctions of a patient's heart is disclosed. The device includes a first modality for sensing an electrical function in the patient's heart and providing a first signal representative of such electrical function, and a second modality for sensing an haemodynamic function in the patient's heart and providing a second signal representative of such haemodynamic function. The device is also provided with first circuitry that is primarily responsive to the signal from one of the sensing modalities for analyzing the state of the heart's function and providing any required electrical shock therapy to the heart. The device further includes second circuitry that is responsive to uncertainty in regard to the therapy to be provided by the first circuitry and is operative to change the responsiveness of the first circuitry to the signal provided by the other of the sensing modalities for controlling the therapy that is to be provided to the heart.

Abstract: An implantable, battery-operated cardioverting/defibrillating pacemaker device with the ability to sense and respond to haemodynamic compromise is described. The ventricular pressure (VP) and electrical activity of the heart are sensed via one or more transvenous or epicardial devices. The filtered peak-to-peak amplitude (VFPPA) and a peak pressure function (VPPF) based upon the right and/or left VP waveform(s) are derived. One of the VFPPA and VPPF, and electrically derived heart rate information, are used in the diagnosis of arrhythmic states. Bradycardia support pacing is initiated and terminated by reference to the VP signal, and the pacing pulse voltage used during bradycardia support pacing is optimized in order to extend battery life of the device. This is done by using the haemodynamic sensor to confirm the presence of an appropriate haemodynamic response to the delivery of bradycardia support pacing, and adjusting the pacing voltage to its lowest efficacious level.

Abstract: An arrhythmia control system and method having automatic determination of the tachycardia confirmation interval. The interval is dynamically set at the minimum of an absolute detection interval and a value calculated as a function of either average sinus interval or tachycardia cycle length or both. The continued presence or the reversion of a pathologic tachycardia can be reliably confirmed, particularly when the patient experiences an elevated heart rate due to, for example, exercise, prior to onset of the tachycardia.

Abstract: A method and apparatus for differentiating between arrhythmia and noise in an antiarrhythmia device. A noise detection criteria is applied to a detected signal so as to detect noise simultaneously at two different sensitivity levels. When noise is not detected on the high gain channel the low gain channel is used for detecting arrhythmias. Arrhythmia therapy is then delivered.