Automated ECG interpretation
Encyclopedia
Automated ECG interpretation is the use of artificial intelligence
and pattern recognition
software and knowledge base
s to carry out automatically the interpretation, test reporting and computer-aided diagnosis
of electrocardiogram
tracings obtained usually from a patient
.
During the 1980s and 1990s, extensive research was carried out by companies and by university labs in order to improve the accuracy rate, which was not very large in the first models. For this purpose, several signal databases with normal and abnormal ECGs were built up by institutions such as MIT and used to test the algorithms and its accuracy.
for analysis and interpretation of ECG recordings with 3 or more leads. Consumer products, such as home ECG recorders for simple,1-channel heart arrhythmia detection, also use basic ECG analysis, essentially to detect abnormalities. Some application areas are:
Translated and reproduced by permission of the author.
Artificial intelligence
Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...
and pattern recognition
Pattern recognition
In machine learning, pattern recognition is the assignment of some sort of output value to a given input value , according to some specific algorithm. An example of pattern recognition is classification, which attempts to assign each input value to one of a given set of classes...
software and knowledge base
Knowledge base
A knowledge base is a special kind of database for knowledge management. A Knowledge Base provides a means for information to be collected, organised, shared, searched and utilised.-Types:...
s to carry out automatically the interpretation, test reporting and computer-aided diagnosis
Computer-aided diagnosis
Computer-aided detection and computer-aided diagnosis are procedures in medicine that assist doctors in the interpretation of medical images. Imaging techniques in X-ray, MRI, and Ultrasound diagnostics yield a great deal of information, which the radiologist has to analyze and evaluate...
of electrocardiogram
Electrocardiogram
Electrocardiography is a transthoracic interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the outer surface of the skin and recorded by a device external to the body...
tracings obtained usually from a patient
Patient
A patient is any recipient of healthcare services. The patient is most often ill or injured and in need of treatment by a physician, advanced practice registered nurse, veterinarian, or other health care provider....
.
History
The first automated ECG programs were developed in the 1970s, when digital ECG machines became possible by third generation digital signal processing boards. Commercial models, such as those developed by Hewlett Packard incorporated these programs into clinically-used devices.During the 1980s and 1990s, extensive research was carried out by companies and by university labs in order to improve the accuracy rate, which was not very large in the first models. For this purpose, several signal databases with normal and abnormal ECGs were built up by institutions such as MIT and used to test the algorithms and its accuracy.
Phases
- A digital representation of each recorded ECG channel is obtained, by means of an analog-digital conversion device and a special data acquisitionData acquisitionData acquisition is the process of sampling signals that measure real world physical conditions and converting the resulting samples into digital numeric values that can be manipulated by a computer. Data acquisition systems typically convert analog waveforms into digital values for processing...
software or a digital signal processingDigital signal processingDigital signal processing is concerned with the representation of discrete time signals by a sequence of numbers or symbols and the processing of these signals. Digital signal processing and analog signal processing are subfields of signal processing...
(DSP) chipIntegrated circuitAn integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
. - The resulting digital signal is processed by a series of specialized algorithmAlgorithmIn mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...
s, which start by conditioningSignal conditioningIn electronics, signal conditioning means manipulating an analog signal in such a way that it meets the requirements of the next stage for further processing...
it, e.g., removal of noise, baselevel variation, etc. - Feature extractionFeature extractionIn pattern recognition and in image processing, feature extraction is a special form of dimensionality reduction.When the input data to an algorithm is too large to be processed and it is suspected to be notoriously redundant then the input data will be transformed into a reduced representation...
: matemathical analysis is now performed on the clean signal of all channels, to identify and measure a number of features which are important for interpretation and diagnosis, this will constitute the input to AI-based programs, such as the peak amplitude, area under the curve, displacement in relation to baseline, etc., of the P, Q, R, S and T waves, the time delay between these peaks and valleys, heart rate frequency (instantaneous and average), and many others. Some sort of secondary processing such as Fourier analysis and wavelet analysis may also be performed in order to provide input to pattern recognition-based programs. - Logical processing and pattern recognition, using rule-based expert systemExpert systemIn artificial intelligence, an expert system is a computer system that emulates the decision-making ability of a human expert. Expert systems are designed to solve complex problems by reasoning about knowledge, like an expert, and not by following the procedure of a developer as is the case in...
s, probabilistic Bayesian analysis or fuzzy logics algorithms, cluster analysis, artificial neural networkArtificial neural networkAn artificial neural network , usually called neural network , is a mathematical model or computational model that is inspired by the structure and/or functional aspects of biological neural networks. A neural network consists of an interconnected group of artificial neurons, and it processes...
s, genetic algorithmGenetic algorithmA genetic algorithm is a search heuristic that mimics the process of natural evolution. This heuristic is routinely used to generate useful solutions to optimization and search problems...
s and others techniques are used to derive conclusions, interpreation and diagnosis - A reporting program is activated and produces a proper display of original and calculated data, as well as the results of automated interpretation.
- In some applications, such as automatic defibrillatorDefibrillationDefibrillation is a common treatment for life-threatening cardiac arrhythmias, ventricular fibrillation and pulseless ventricular tachycardia. Defibrillation consists of delivering a therapeutic dose of electrical energy to the affected heart with a device called a defibrillator...
s, an action of some sort may be triggered by results of the analysis, such as the occurrence of an atrial fibrillationAtrial fibrillationAtrial fibrillation is the most common cardiac arrhythmia . It is a common cause of irregular heart beat, identified clinically by taking a pulse. Chaotic electrical activity in the two upper chambers of the heart result in the muscle fibrillating , instead of achieving coordinated contraction...
or a cardiac arrestCardiac arrestCardiac arrest, is the cessation of normal circulation of the blood due to failure of the heart to contract effectively...
, the sounding of alarms in a medical monitorMedical monitorA medical monitor or physiological monitor or display, is an electronic medical device used in medical monitoring that displays the monitored data, and may or may not have the ability to transmit the data on a monitoring network...
in intensive-care unit applications, and so on.
Applications
The manufacturing industries of ECG machines is now entirely digital, and many models incorporate embedded softwareEmbedded software
Embedded software is computer software that plays an integral role in the electronics it is supplied with.Embedded software's principal role is not Information technology , but rather the interaction with the physical world. It's written for machines that are not, first and foremost, computers...
for analysis and interpretation of ECG recordings with 3 or more leads. Consumer products, such as home ECG recorders for simple,1-channel heart arrhythmia detection, also use basic ECG analysis, essentially to detect abnormalities. Some application areas are:
- Incorporation into automatic defibrillators, so that autonomous decision can be reached wheter there is a cause for administering the electrical shock on basis of an atrial or ventricular arryhtmia;
- Portable ECG used in telemedicineTelemedicineTelemedicine is the use of telecommunication and information technologies in order to provide clinical health care at a distance. It helps eliminate distance barriers and can improve access to medical services that would often not be consistently available in distant rural communities...
. These machines are used to send ECG recordings via a telecommunications link, such as telephoneTelephoneThe telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other...
, cellular data communication or InternetInternetThe Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide... - Conventional ECG machines to be used in primary healthcare settings where a trained cardiologist is not available
Source
- Sabbatini, RME: O computador no processamento de sinais biológicos. Revista Informédica, 2 (12): 5-9, 1995. Computers in the processing of biological signals. (In Portuguese)
Translated and reproduced by permission of the author.