Method of deriving standard 12-lead electrocardiogram and electrocardiogram monitoring apparatus

• US 20020045837A1
• Filed: 07/24/2001
• Published: 04/18/2002
• Est. Priority Date: 07/24/2000
• Status: Active Grant

• Current Assignee: Nihon Kohden Corporation
• Original Assignee: Nihon Kohden Corporation
• Inventors: Sakai, Yoshio, Kojima, Takeshi, Wei, Daming, Nakayama, Tadashi
• Granted Patent: US 6,721,591 B2
• Time in Patent Office: Days
• US Class Current: 600/509
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/327 Generation of artificial ECG signals based on measured signals, e.g. to compensate for missing leads
• CPC Class Codes: A61B 5/332 Portable devices specially adapted therefor
• CPC Class Codes: A61B 5/333 Recording apparatus specially adapted therefor
• CPC Class Codes: A61B 5/338 Recording by printing on paper

Abstract

A plurality of electrodes for measuring electrocardiogarphic waveforms are attached on body surface positions that constitute a subset of the standard 12-lead system. The measured electrocardiogarphic waveforms of said subset of said standard 12-lead system are used to calculate the electrocardiogarphic waveforms of remaining leads in the said standard 12-lead system. The measured and calculated electrocardiographic waveforms are synthesized to form a standard 12-lead electrocardiogram. The invention is capable of monitoring the 12-lead electrocardiogram with reduced number of electrodes, wherein a portion of waveforms are directly measured and used as primary information for diagnosing heart disease, and the other portion of waveforms are derived from the measured leads and are used as a secondary information for improving the accuracy of diagnosis. The invention is especially useful in monitoring ischemic heart disease and acute myocardial infarction in cases where mounting and maintaining ten electrodes to obtain 12-lead electrocardiogram is difficult, such as in ambulatory monitoring, long-term monitoring and home monitoring.

Claims

1. A method of deriving a standard 12-lead electrocardiogram comprising the steps of:

attaching a plurality of electrodes for sensing and measuring body surface potentials on positions that constitute a subset of a standard 12-lead system;

measuring the electrocardiogarphic waveforms for said subset of said standard 12-lead system from potentials sensed by said plurality of electrodes;

calculating waveforms of remaining leads of said standard 12-lead system from said measured electrocardiographic waveforms;

deriving the standard 12-lead electrocardiogram using said measured electrocardiographic waveforms and said calculated electrocardiographic waveforms.

2. A method of deriving a standard 12-lead electrocardiogram according to claim 1, wherein said standard 12-lead system is the 12-lead system used in routing rest 12-lead electrocardiogram testing.

3. A method of deriving a standard 12-lead electrocardiogram according to claim 1, wherein said standard 12-lead system is the 12-lead system used in routing exercise 12-lead electrocardiogram testing, called M-L lead system.

4. A method of deriving a standard 12-lead electrocardiogram according to claim 1, wherein an intermediate quantity, namely heart vector, is obtained on the basis of the values of said measured waveforms of said subset of said standard 12-lead system in view of coefficient vectors, called lead vectors, of said measured leads, which reflect the inherent relationship among values of measured waveform and said heart vector;

and wherein the values of waveforms of said remaining leads of said standard 12-lead system are calculated using said heart vector and the lead vectors of said remaining leads.

5. A method of deriving a standard 12-lead electrocardiogram according to claim 1, wherein said plurality of electrodes for sensing and measuring body surface potentials on positions that constitute a subset of the standard 12-lead system contain positions of RA, LA, RL, LL, V1, and V6 in said standard 12-lead system, based on which the electrocardigraphic waveforms of leads I, II, V1, and V6 are measured, and thereafter the electrocardigraphic waveforms of leads III, aVR, aVL, and aVF are derived based on the relationship among the limb leads, and leads V2, V3, V4, V5 are derived using values of waveforms of leads I, II, V1, and V6 with said method of deriving a standard 12-lead electrocardiogram.

6. A method of deriving a standard 12-lead electrocardiogram according to claim 1, wherein said plurality of electrodes for sensing and measuring body surface potentials on positions that constitute a subset of said standard 12-lead system contain positions of RA, LA, RL, LL, V1, and V5 in said standard 12-lead system, based on which the electrocardigraphic waveforms of leads I, II, V1, and V5 are measured, and thereafter the electrocardigraphic waveforms of leads III, aVR, aVL, and aVF are derived , and leads V2, V3, V4, V6 are derived using values of waveforms of leads I, II, V1, and V5 with said method of deriving a standard 12-lead electrocardiogram.

7. An electrocardiogram monitoring apparatus comprising:

a plurality of electrodes, attached to the surface of a living body, for sensing and measuring body surface potentials on positions that constitute a subset of said standard 12-lead system;

a potentials detector for detecting potentials sensed by said plurality of electrodes;

an operational amplifier for detecting and amplifying signals of electrocardiogram from the input of said potentials detector;

a 12-lead electrocardiogram operation unit for calculating waveforms of said remaining leads using signals from said operational amplifier and derive 12-lead waveforms for display;

a 12-lead electrocardiogram display unit for displaying 12-lead electrocardiogram using input from said 12-lead electrocardiogram operation unit.