摘要:
In an implantable cardiac device, atrial signals, spaced either spatially or temporally, are sensed and stored. The morphology of the signals are compared and an atrial fibrillation indication is generated if the signals are different. The device then either changes its mode of operation or applies appropriate therapy.
摘要:
A cardiac implant device is provided in which the ventricular rate is monitored to differentiate between atrial fibrillation and ventricular tachycardia or other cardiac conditions. For this purpose, the ventricular rate stability is monitored by, for example, measuring the R-R intervals of successive ventricular beats. If the ventricular rate is found to be unstable, the ventricle is paced at a test rate to try to stabilize the ventricle. If the attempt is unsuccessful, atrial fibrillation is assumed and, if necessary, corresponding therapy is applied. If the attempt is unsuccessful, atrial fibrillation is eliminated as a cause of the ventricular rate instability and other types of classifying and treating the cardiac condition may be used.
摘要:
A medical device and associated method obtaining cardiac event intervals corresponding to a tachycardia interval. Evidence of a rhythm breaking point is obtained in response to sensing a cardiac event having a morphology corresponding to a supraventricular beat. A non-treatable rhythm is detected in response to the plurality of cardiac event intervals and the evidence of the rhythm breaking point.
摘要:
An implantable medical device system including an intraventricular pressure sensor controls an atrioventricular (AV) delay based on the intraventricular pressure signal. An atrial kick pressure waveform corresponding to active contraction of an atrial chamber is detected from the intraventricular pressure signal. In one embodiment, a time interval corresponding to the atrial kick pressure waveform is measured. An AV delay is set in response to the measured time interval.
摘要:
An implantable medical device system and method are provided for monitoring the quality of signals sensed by a subcutaneously implanted device using subcutaneous electrodes. In one embodiment, the method includes selecting one or more sensing vectors; sensing signals from selected sensing vectors, determining a signal quality metric in response to a sensed signal, comparing the signal quality metric to a predetermined threshold, and generating a loss of signal quality response in response to the signal quality crossing the threshold.
摘要:
The cardiac condition of a patient is determined by a cardiac monitor apparatus using a respiration parameter such as a current respiration signal or a respiration rate. The variability of the respiration parameter is used to generate a signal indicative of the current heart failure status of the patient, and more particularly whether the patient's condition has improved, worsened, or remained unchanged over a predetermined time period. The circuitry for detecting the respiration parameter may be implanted in the patient, for example as part of a pacemaker, while at least some of the analyzing circuitry may be external and remote from the patient. Alternatively the whole device may be implantable.
摘要:
An implantable atrial defibrillator analyzes both the atrium and the ventricle to determine an abnormal atrial condition of the atrium and if the ventricle is unstable. Therapy is applied to correct the abnormal atrial condition, such as atrial fibrillation, only if the ventricle is stable, to insure that the therapy does not provoke a ventricular tachyarrhythmia. If the ventricle is unstable, first a process is performed to stabilize it, for example by using a ventricular pacing protocol. After the ventricle is stabilized, the atrial therapy is applied in synchronism with the ventricular events (i.e., in synchronism with either ventricular intrinsic events or ventricular pacing pulses.)
摘要:
In an implantable pacemaker the pacing rate is adjusted in synchrony with the respiration of the patient to thereby mimic respiratory sinus arrhythmia noted in healthy patients. Preferably, first a metabolic demand parameter pacing parameter is derived from a metabolic demand of the patient, such as minute volume, and then this parameter is adjusted using a respiration detector. The adjustment may be made dependent on the exercise level of the patient, his age and his physical fitness.
摘要:
A diagnostic device makes use of knowledge based rule system for making a prognosis of a cardiac malfunction based on operation parameters and/or patient characteristics received from a cardiac implant. The device generates a symptoms vector from the information received from the implant, and using the expert rules to generate an appropriate prognosis. Both pathological problems and programming problems may be detected in this manner.
摘要:
A pacemaker operating in an AAI or AAIR mode is provided with a detector for monitoring an atrial lead and detecting cross talk or far field R-waves from the ventricle. This signal is used to detect and monitor AV nodal block and its progression in a patient. The same signal may also be used to indicate atrial capture.