Abstract: An apparatus and method for the acquisition and analysis of electrocardiogram signals, to non-invasively detect and quantify presence of abnormal cardiac conduction patterns in patients at risk of heart disease, e.g. ventricular tachycardia; atrial fibrillation and flutter. Signals from the orthogonal X, Y and Z surface leads are amplified, digitized and either stored for later processing, or processed immediately. The incoming beats can either be R wave-triggered, aligned and ensemble-averaged for studies of patients at risk for ventricular pathologies such as ventricular tachycardia, or P wave-triggered, aligned and ensemble-averaged for studies of patients at risk for atrial pathologies, e.g. atrial fibrillation and flutter. QRS onset and offset, and P wave onset and offset, are calculated for ventricular and atrial post-analysis applications, respectively.

Abstract: A system for predicting ventricular tachycardia from electrocardiograph input waveforms. A high pass filter provides an output responsive to the input waveforms. A time derivative of the filter output is generated to produce waveforms which can be compared to a standard. In one embodiment, the input waveforms are digitized prior to processing by the filter means. In another embodiment, digitized input waveforms are signal averaged prior to processing by the filter. The filter can be a finite impulse response filter of an infinite impulse response filter. In an alternate embodiment, a ventricular tachycardia prediction system for use with ECG waveforms having cyclical characteristics is disclosed. The ECG waveforms are periodically sampled during each of a plurality ECG cycles. A filter unidirectionally filters the signals for each ECG cycle so as to provide a filter output systematically related to the high frequency content of the input. A reference signal is provided for ventricular tachycardia prediction.

Abstract: A ventricular tachycardia (VT) prediction system for use with an ECG input having cyclical characteristics. The ECG input is periodically sampled during each of a plurality of ECG cycles, and signals representative of the ECG input for each corresponding sample time are stored. A high pass filter adaptively filters the signals for each ECG cycle, so as to provide a filter output systematically related to the high frequency content of the ECG input. The adaptive filter produces segments which are uninfluenced by other samples so as to negate ringing. A reference signal is provided for VT prediction. The filter output is compared to the reference signal, and the prediction of ventricular tachycardia is indicated responsive to the comparison. In one embodiment the samples are averaged for a plurality of ECG cycles prior to generating the filter output. In another embodiment, the system determines the duration of the QRS portion of the ECG cycles prior to generating the filter output.

Abstract: A system for predicting ventricular tachycardia from electrocardiograph input waveforms. A first means generates a signal representative of the input waveforms exceeding a preselected level. A second filter means has its gain controlled responsive to the first means output signal, and provides an output responsive to said input waveforms. Ventricular tachycardia is then predicted responsive to the second filter means output. In one embodiment, the input waveforms are digitized prior to processing by the first and second means. In another embodiment, the input waveforms are signal averaged prior to processing by the first and second means.