US 4,393,877 A · Heart rate detector

Abstract

A heart rate detector apparatus, particularly for use in an implantable defibrillator, is disclosed. The heart rate detector apparatus includes two distinct detector circuits each responsive to ECG waveforms of different characteristics. One of the detector circuits is responsive to ECG waves having slew rates above a predetermined threshold. The other detector circuit is responsive to ECG waves having lower slew rates, such as ECG waves of more sinusoidal shape. A coupling circuit automatically couples one of the two detector circuits to an output circuit, such as a heart rate comparator. In a specific embodiment, the heart rate comparator determines the heart rate, compares the heart rate with a predetermined rate, and, if the heart rate exceeds the predetermined rate for a predetermined time period, provides an output signal. The output signal may be used to enable a defibrillating circuit to deliver a defibrillating shock to the patient.

Claims37

Dependent claims

A heart beat rate detector responsive to incoming ECG signals comprising:

input means for receiving an ECG signal;
wave detector means operatively coupled with the input means for detecting an ECG waveshape having a slew rate above a predetermined threshold and providing a wave detector output signal for each detected waveshape;
zero-crossing detector means operatively coupled with the input means for detecting an ECG waveshape having a predetermined amplitude and providing a zero-crossing output signal for each detected waveshape;
output means for receiving the wave detector output signal and zero-crossing output signal;
and
coupling means for selectively coupling only one of said wave detector means and zero-crossing means with said output means.

3 more elements

A system for use with an automatic defibrillator for defibrillating the heart of a patient experiencing abnormal cardiac rhythm, comprising:

input means for receiving ECG waveforms;
processing means coupled with said input means for processing the ECG waveforms in accordance with a probability density function to develop a probability density function output signal;
a heart rate detector coupled between said input means and a processing output means, said heart rate detector comprising,
first detecting means for detecting an ECG wave packet by detecting a first characteristic of said wave packet and providing a first output signal when said wave packet is detected;
second detecting means for detecting an ECG wave packet by detecting a second characteristic of said wave packet and providing a second output signal when said wave packet is detected;
rate detector output means for receiving the first and second output signals and for providing a rate detector output signal to the processing output means when the aggregate number of first and second output signals exceed a predetermined rate;
and
coupling means for selectively coupling only one of said first and second detecting means with said rate detector output means whereby the aggregate number of first and second output signals represents the number of heart beats;
and
processing output means for coupling said processing means and heart rate detector with a defibrillating pulse generator for initiating the discharge of a defibrillating shock upon receiving a predetermined signal from at least one of said processing means and said heart rate detector.

7 more elements

Dependencies are inferred from the claim text.

Heart rate detector

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Heart rate detector

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Abstract

Claims37