Abstract: A cardiac arrest monitor and alarm system including an implantable medical device having at least three subcutaneous electrodes positioned with respect to a heart organ and forming a subcutaneous orthogonal lead configuration to continuously monitor an electrocardiographic signal of the heart organ. An implantable microdevice, operatively connected to the subcutaneous medical device, detects a deviation from a normal heart electrical activity and emits a signal to an external receiver. Upon verification of the signal from the microdevice, the external receiver activates a programmed annunciator circuit to alert bystanders and activate a communication link automatically transmitting an alarm and the electrocardiographic signal to a remote transceiver.

Abstract: A cardiac arrest monitor and alarm system including an implantable medical device having at least three subcutaneous electrodes positioned with respect to a heart organ and forming a subcutaneous orthogonal lead configuration to continuously monitor an electrocardiographic signal of the heart organ. An implantable microdevice, operatively connected to the subcutaneous medical device, detects a deviation from a normal heart electrical activity and emits a signal to an external receiver. Upon verification of the signal from the microdevice, the external receiver activates a programmed annunciator circuit to alert bystanders and activate a communication link automatically transmitting an alarm and the electrocardiographic signal to a remote transceiver.

Abstract: An in-vitro testing system to assist in optimal programming of an ICD is provided which avoids the inconvenience and health risk associated with repetitive inductions of an arrhythmia. The system includes a high speed computer having analog-to-digital and digital-to-analog subsystems. The system includes software which provides real-time capture and storage of a patient's electrogram. Subsequently, the electrogram may be played and replayed into ICD software simulators at a variety of settings to determine candidate programming parameters. The system further includes an attenuator through which signals are fed on their way to an ICD. This arrangement provides a method by which validation of the simulation system may be achieved. The system also provides for the capture of output event markers simultaneously with the signal into a digital file for assessment of device performance.

Abstract: A method and appartus for differentiating between ventricular tachycardia and ventricular fibrillation includes a pair of electrodes located on a single catheter which, in conjunction with an implantable cardioverter device, utilize two channel ventricular algorithms for ventricular tachycardia and ventricular fibrillation separation. Two closely spaced unipolar electrograms demonstrate similar morphology and consistency during rhythms with broad coherent activation (such as sinus rhythm and ventricular tachycardia). Conversely, for incoherent rhythms (ventricular fibrillation and polymorphic ventricular tachycardia), activation between the electrodes proved to be dissimilar and inconsistent. The cross-correlation of the two depolarizations measures similarity between electrogram morphology, and interquartile range measures consistency in a passage.

Abstract: A pattern recognition system for use in an implantable cardioverter defibrillator that is capable of responding correctively to abnormal activity of the heart efficiently and specifically. The system of the present invention first establishes a template standard defining a median or other statistical measure of central tendency representing the point above which or below which actual sample values would be remarkable. Against the median are compared sampled values within a window having a pre-programmed length. For each cycle, a comparison is made between the template median and every value sampled within this pre-programmed window. Each cycle is then individually diagnosed such that if a selected value is above a particular pre-established threshold or below a particular pre-established threshold it will be classified as abnormal. A plurality of specific cycles must be classified abnormal in order for a final diagnosis to be made that the individual is experiencing arrhythmia.

Abstract: A method and system are provided for monitoring electrocardiographic signals and detecting a pathological cardiac arrhythmia, such as ventricular tachycardia wherein the zero crossings of the first derivative of a reference template (i.e. reference waveform) are utilized to separate or partition both the template and each subsequent electrocardiographic signal being monitored into first and second sets of identifiable partitions. Each zero crossing is a boundary between adjacent partitions. Initially, the reference template is generated by acquiring a first set of wavefrom data representing a known good electrocardiographic signal. Identifiable partitions of the first set of data are then matched with corresponding identifiable partitions of the second set of data to obtain a performance measure signal. In one embodiment, the area beneath the derivative in each partition of the analyzed waveform is computed and compared (i.e. matched) to the corresponding area of the template.