Apparatus and method for detecting heart characteristics by way of electrical stimulation
First Claim
1. An apparatus for detecting heart characteristics, comprising:
- a plurality of ECG detecting electrodes;
a blood pressure (BP) sensor;
a preamplifier circuit, whose inputs are connected respectively to said ECG detecting electrodes and said BP sensor, for providing parallel multiplex outputs of ECG and BP signals;
an A/D convertor, whose inputs are connected to said parallel multiplex outputs of said preamplifier circuit, for converting said analog ECG and BP signals into digital data;
a data processing unit, whose inputs are connected to the digital output of said A/D convertor, for processing said digital data to generate stimulating instructions and to identify waveforms of said ECG and BP signals;
a stimulating signal generating unit for generating heart stimulation signals under the control of said stimulating instructions issued by said data processing unit;
two pairs of intracardiac electrodes, which are connected to the outputs of said stimulating signal generating unit, for applying said heart stimulation signals to atrium and ventricle, respectively; and
an input-output device, which is connected to said data processing unit for inputting operating instructions therein and providing its processed results and identified waveforms as output;
wherein said data processing unit includes means for processing the ECG and BP signals detected by said ECG detecting electrodes and BP sensor, and for issuing instructions for heart stimulation to said stimulating signal generating unit according to said processed results, said stimulating signal generating unit generating stimulating signals of specific waveforms according to said instructions and applying said stimulating signals to atrium and ventricle, respectively, via said intracardiac electrodes, said data processing unit including means for identifying the change of ECG and BP waveforms under the effects of the stimulating signals, for issuing instructions for stopping stimulation to said stimulating signal generating unit upon the identification of ME (NST) or VT waveforms, and for providing the identified waveforms and the amplitude of the stimulating signal which induces said waveforms to said input-output device.
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Abstract
The apparatus and method of the present invention are used to detect the ECG and/or blood pressure (BP) waveforms and measure the R-R and Q-T intervals from the detected ECG signals, so as to determine the pulse structure of the heart stimulating signals, and to stimulate the heart. The heart is stimulated by the stimulating signals which includes a pacing pulse train applied to atrium for forming an artificial heart rhythm, and an inducing pulse train applied to ventricle for introducing ME or VT waveforms. By adjusting the time location and amplitude of the inducing pulses relative to the pacing pulses, the ME or VT waveforms are induced in the ECG signals. By detecting the ECG and/or BP waveforms, the ME or VT is identified and at the same time the heart stimulation is stopped. Then the induced ME or VT waveforms and the amplitude of the inducing pulse which induces the ME or VT waveforms are displayed and the ventricular fibrillation threshold is derived according to this amplitude.
97 Citations
18 Claims
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1. An apparatus for detecting heart characteristics, comprising:
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a plurality of ECG detecting electrodes; a blood pressure (BP) sensor; a preamplifier circuit, whose inputs are connected respectively to said ECG detecting electrodes and said BP sensor, for providing parallel multiplex outputs of ECG and BP signals; an A/D convertor, whose inputs are connected to said parallel multiplex outputs of said preamplifier circuit, for converting said analog ECG and BP signals into digital data; a data processing unit, whose inputs are connected to the digital output of said A/D convertor, for processing said digital data to generate stimulating instructions and to identify waveforms of said ECG and BP signals; a stimulating signal generating unit for generating heart stimulation signals under the control of said stimulating instructions issued by said data processing unit; two pairs of intracardiac electrodes, which are connected to the outputs of said stimulating signal generating unit, for applying said heart stimulation signals to atrium and ventricle, respectively; and an input-output device, which is connected to said data processing unit for inputting operating instructions therein and providing its processed results and identified waveforms as output; wherein said data processing unit includes means for processing the ECG and BP signals detected by said ECG detecting electrodes and BP sensor, and for issuing instructions for heart stimulation to said stimulating signal generating unit according to said processed results, said stimulating signal generating unit generating stimulating signals of specific waveforms according to said instructions and applying said stimulating signals to atrium and ventricle, respectively, via said intracardiac electrodes, said data processing unit including means for identifying the change of ECG and BP waveforms under the effects of the stimulating signals, for issuing instructions for stopping stimulation to said stimulating signal generating unit upon the identification of ME (NST) or VT waveforms, and for providing the identified waveforms and the amplitude of the stimulating signal which induces said waveforms to said input-output device. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for detecting heart characteristics, comprising:
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a plurality of ECG detecting electrodes; a preamplifier circuit, whose inputs are connected to said ECG detecting electrodes, for providing ECG output; an A/D convertor for converting said ECG output into digital data; a data processing unit, whose input is connected to the digital output of said A/D convertor, for processing said digital data; an input-output device connected to said data processing unit for inputting operating instructions and information thereto and providing the processed results and identified waveforms therefrom as output; two pairs of dual path intracardiac electrodes for applying said heart stimulation signals to atrium and ventricle, respectively; a stimulating signal generating unit having outputs connected to the dual-path heart stimulating electrodes; and an earth-floating circuit connected between said preamplifier circuit and said A/D convertor, for preventing electric interference on the ECG signals detected by said preamplifier circuit when the stimulating pulses are applied to heart by said stimulating signal generating unit; wherein, said data processing unit includes means for processing ECG signals detected via said ECG detecting electrodes, for issuing heart stimulation instructions to said stimulating signal generating unit according to the processed results, said stimulating signal generating unit generating stimulating signals of specific pulse structure according to the information provided by said instructions and applying said stimulating signals to atrium and ventricle respectively via said heart stimulating electrodes;
said data processing unit including means for identifying the waveform of PVC, ME or VT in ECG signals under the effects of said stimulating signals, for issuing instructions for stopping heart stimulation to said stimulating signal generating unit upon the identification of said waveform, and for providing the identified waveform and the amplitude of the pulse which induces said waveform to said input-output device as output. - View Dependent Claims (8, 9, 10)
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11. A method for detecting heart characteristics, comprising the steps of:
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a. detecting ECG and BP waveforms via ECG detecting electrodes and a BP sensor; b. measuring R--R interval, Q-T interval, shift of ST segment from detected ECG signals and calculating the diastolic BP values from detected BP signals; c. applying via intracardiac electrodes, a pacing pulse train to right atrium, with the period of said pacing pulse being 50-80% of said R--R interval and the amplitude being in the range of 1-20 mA; d. applying via intracardiac electrodes, an inducing pulse to right ventricle after each group of N pacing pulses with the amplitude of said inducing pulse being less than 0.2 mA and preferably 0.1 mA, and applying said inducing pulse within the range from the start point to the peak point of T wave, wherein N is in the range of 1-10; e. detecting, when said inducing pulse is applied, whether the BP waveform is lower than said diastolic BP value and the duration of the BP decrease;
wherein step d is repeated when no BP decrease is detected with the location of said inducing pulse being delayed 4-10 mS relative to the start point, within the range from the start point to the peak point of T wave, until the whole range is scanned;f. increasing the amplitude of said inducing pulse by an increment of about 0.1 mA and repeating the above steps d and e, untl detected BP value is lower than said diastolic BP value for the time duration longer than a predetermined value; g. stopping the application of said pacing and inducing pulses to the heart and providing via output device the ECG waveforms corresponding to said BP decrease and the amplitude of the inducing pulse which induces said waveform for display. - View Dependent Claims (12, 13, 14)
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15. A method for detecting heart characteristics comprising the steps of:
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a. detecting ECG signals by ECG detecting electrodes; b. measuring the R--R interval and Q-T interval of the detected ECG signals; c. applying, via stimulating electrodes, a pacing pulse train to atrium with a period Tso being 50-80% of said R--R interval and an amplitude being 1-20 mA; d. applying, via the other stimulating electrodes, an inducing pulse train to ventricle to induce ME or VT waveforms by adjusting the time location and amplitude of said inducing pulses relative to said pacing pulses; e. identifying the anomalous heart beats having R--R interval less than said pacing period Tso induced by said inducing pulses and repeating step d until said anomalous heart beats are induced; and f. stopping the application of said pacing pulse train to atrium and said inducing pulse train to ventricle upon the identification of said anomalous heart beats, and providing the waveforms of said anomalous heart beats and the amplitude of the inducing pulse which induces said waveforms to output device for display. - View Dependent Claims (16, 17, 18)
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Specification