Apparatus for detecting heart characteristics using electrical stimulation

Claim 1

Apparatus for determining the electro-cardiac stability of the heart, comprising: an input adapted for connection to ECG electrodes; a pre-amplifier (30) and convertor (40) adapted to convert ECG signals from the input into digital form; a signal generating unit (60) for generating specific stimulating pulses at an output adapted for connection to cardiac stimulating electrodes, on the basis of instructions received from a data processing unit (50) set up to perform the operations of: initiating production of appropriate stimulating pulses by said signal generating unit; monitoring the digital ECG data so as to detect the presence of characteristic anomalous ECG waveforms induced by the stimulating pulses; instructing the signal generating unit (60) to stop producing stimulating pulses on detection of the anomalous waveforms; characterised in that the data processing unit (50) is set up to:- (i) instruct the cessation of stimulation on detection of the anomalous waveforms without ventricular fibrillation being induced, these wave forms being characteristic of ME (NST) or VT (optionally also PVC); (ii) calculate the ventricular fibrillation threshold (VFT) from the amplitude of the stimulating pulse or pulses that induced the detected anomalous ECG waveform, and (iii) show on an output display (80) the calculated value of VFT.

Claim 3

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 operationg instructions there­in and providing its processed results and identified wave­forms as output; wherein, said data processing unit first processes the ECG and BP signals detected by said ECG detecting electrodes and BP sensor, then issues instructions for heart stimulation to said stimulating signal generating unit according to said processed results, said stimulating signal generating unit generates stimulating signals of specific waveforms according to said instructions and applies said stimulating signals to atrium and ventricle, respectively, via said intracardiac electrodes, at the same time said data processing unit identifies the change of ECG and BP waveforms under the effects of the stimulating signals and issues instructions for stopping stimulation to said stimulating signal generat­ing unit upon the identification of ME (NST) or VT waveforms, then provides the identified waveforms and the amplitude of the stimulating signal which induces said waveforms to said input-output device.

Claim 4

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 operationg instructions there­in and providing its processed results and identified wave­forms as output; wherein, said data processing unit first processes the ECG and BP signals detected by said ECG detecting electrodes and BP sensor, then issues instructions for heart stimulation to said stimulating signal generating unit according to said processed results, said stimulating signal generating unit generates stimulating signals of specific waveforms according to said instructions and applies said stimulating signals to atrium and ventricle, respectively, via said intracardiac electrodes, at the same time said data processing unit identifies the change of ECG and BP waveforms under the effects of the stimulating signals and issues instructions for stopping stimulation to said stimulating signal generat­ing unit upon the identification of ME (NST) or VT waveforms, then provides the identified waveforms and the amplitude of the stimulating signal which induces said waveforms to said input-output device.

Claim 10

An apparatus for detecting heart characteristics, compris­ing: 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; a stimulating signal generating unit having outputs con­nected to 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 during the process the stimulating pulses being appl­ied to heart by said stimulating signal generating unit; wherein, said data processing unit first processes ECG si­gnals detected via siad ECG detecting electrodes, issues ins­tructions for heart stimulating to said stimulating signal generating unit according to the processed results, the said stimulating signal generating unit generates stimulating sig­nals of specific pulse structure according to the information provided by said instructions and applies said stimulating signals to atrium and ventricle respectively via said heart stimulating electrodes; at the same time said data processing unit identifies the waveform of PVC, ME or VT in ECG signals under the effects of said stimulating signals, issues ins­tructions for stopping heart stimulating to said stimulating signal generating unit upon the identifying of said waveform, and provides the identified waveform and the amplitude of the pulse which induces said waveform to said input-ouput device as output.

Claim 11

An apparatus for detecting heart characteristics, compris­ing: 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; a stimulating signal generating unit having outputs con­nected to 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 during the process the stimulating pulses being appl­ied to heart by said stimulating signal generating unit; wherein, said data processing unit first processes ECG si­gnals detected via siad ECG detecting electrodes, issues ins­tructions for heart stimulating to said stimulating signal generating unit according to the processed results, the said stimulating signal generating unit generates stimulating sig­nals of specific pulse structure according to the information provided by said instructions and applies said stimulating signals to atrium and ventricle respectively via said heart stimulating electrodes; at the same time said data processing unit identifies the waveform of PVC, ME or VT in ECG signals under the effects of said stimulating signals, issues ins­tructions for stopping heart stimulating to said stimulating signal generating unit upon the identifying of said waveform, and provides the identified waveform and the amplitude of the pulse which induces said waveform to said input-ouput device as output.