Cardiac arrhythmia detector using ECG waveform-factor and its irregularity
First Claim
1. A cardiac monitor for determining the cardiac condition of a patient comprising:
- a sensor that senses the intrinsic activity of a patient'"'"'s heart and generates a corresponding sensed signal;
an interval detector that detects an interval associated with a cardiac cycle based on said sensed signal;
a waveform factor detector that detects a waveform factor from said sensed signal, said waveform factor being a function of a ratio of a mean value of said signal during said cardiac cycle and a peak value of said signal during said interval; and
a first comparator that compares said waveform factor to a threshold and generates a corresponding for first output indicative of the patient'"'"'s cardiac condition.
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Accused Products
Abstract
A cardiac monitor is provided that monitors the condition of the heart of a cardiac patient and generates signals indicating one of several conditions, such as supraventricular tachycardia, ventricular tachycardia and ventricular fibrillation. In order to generate these signals, the ECG from the patient is analyzed to determine a cardiac interval and heart rate, as well as a waveform factor and a waveform factor irregularity. The waveform factor is derived from the average of the ECG amplitudes during a cardiac interval and the peak value of the ECG during the same interval. Preferably, a running average is calculated over several intervals. This waveform factor is then used to detect shockable ventricular arrhythmia. The waveform factor irregularity is indicative of the variability of the waveform factor and is used to differentiate between ventricular tachycardia and ventricular defibrillation.
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Citations
20 Claims
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1. A cardiac monitor for determining the cardiac condition of a patient comprising:
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a sensor that senses the intrinsic activity of a patient'"'"'s heart and generates a corresponding sensed signal;
an interval detector that detects an interval associated with a cardiac cycle based on said sensed signal;
a waveform factor detector that detects a waveform factor from said sensed signal, said waveform factor being a function of a ratio of a mean value of said signal during said cardiac cycle and a peak value of said signal during said interval; and
a first comparator that compares said waveform factor to a threshold and generates a corresponding for first output indicative of the patient'"'"'s cardiac condition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A cardiac therapy device adapted to selectively provide shock therapy to a patient, comprising:
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a sensor adapted to detect intrinsic activity in the patient'"'"'s heart and to generate a corresponding sensed signal;
a pulse generator adapted to generate therapy pulses in response to control signals;
a monitor adapted to classify a cardiac condition and to generate a corresponding heart condition signal; and
a controller adapted to receive said heart condition signal and to generate in response said control signals;
wherein said monitor includes;
an interval detector that detects an interval associated with a cardiac cycle based on said sensed signal;
a waveform factor detector that detects a waveform factor from said sensed signal, said waveform factor being a function of a ratio of a mean value of said sensed signal during said cardiac cycle and a peak value of said sensed signal during said interval; and
a first comparator that compares said waveform factor to a threshold and generates a corresponding first output indicative of the patient'"'"'s cardiac condition. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification