Evolution of cardiographs: from rooms with salt baths to iPhone cases
Cardiovascular diseases take the first place in the list of the main threats of mankind from the second half of the last century. We decided to consider the evolutionary path of cardiogram recording devices - after all, the availability and ease of diagnosis play a decisive role in the struggle for the health of people all over the world.
Evolution of electrocardiographs in the 20-21 centuries: a) Cambridge Scienti Instrument Company, 1910-1911; b) Sanborn Cardiette Model 51, 1939; c) EK1T-03M, 1976; d) Contec ECG80A, 2012
Health and safety are basic needs. Health is our primary resource. We invest it on a par with our work and skills. Naturally, I would like to know the state of this resource and understand the return it brings.
')
Today, many are beginning to understand that you need to deal with their health regularly. To restore it with our level of “free” medicine costs huge funds and the same nerves, that is, the remnants of health. This is what developed countries understand as the economy or the “industry” of health. While the Russian state is considering the object of attention of an unhealthy person, and disease prevention is reduced to an increase in excise taxes on tobacco and alcohol, we have to deal with the arrival and consumption of this resource on our own.
So the facts. The main resource of the human body is the heart. Today, death rates from cardiovascular diseases in Russia are ominous . In Europe, in general, things are a little better . We can call the new pattern of behavior the familiar word "prevention." The essence of this will not change. There are two options: regular visits to the doctor, clinical examination (that is, diagnosis on professional equipment) and self-diagnosis using a modern compact device.
The first option is associated with obvious costs (time, money), but gives the result provided by the professionalism of the doctor and the level of equipment. The second option is commercial portable devices for monitoring vital signs and health. In the last decade, this market has been actively developing, but until now there have been constant discussions about the practical value around the so-called wearable devices.
If we are engaged in the economy of our health, we need a guaranteed, accurate result with a minimum of costs. Are there any professional-level devices for self-diagnostics on the market? An example of the mass distribution of portable blood pressure monitors for pressure testing answers this question in the affirmative.
On the memory of one generation, the tonometer turned from a massive carbolite canister with a mercury indicator, a rubber bulb pump and a phonendoscope into a compact automatic device equipped with built-in memory and data analysis function. Its accuracy is sufficient for the initial diagnosis.
What happens in electrocardiography? It turns out that progress in this direction is also impressive. A modern smartphone-compatible heart monitor provides clinical-quality data. But to understand how this works, you need to turn to history.
Cardiology is a relatively young science. Until the beginning of the 20th century, infections were the main enemy of mankind. If the method of measurement and the first device for measuring blood pressure were invented in the middle of the 18th century by the British priest Stephen Heiles, then with cardiography I had to wait another couple of centuries.
The first statistics on cardiovascular diseases appeared in the United States with the beginning of the work of the American Heart Association in 1924. Interest in the problem has a clear historical and territorial link. It was in the 20s of the last century that North America experienced a boom in the production of sweet soft drinks. Sugar consumption jumped from 10-15 to 100 pounds per person per year (today 150 pounds). Began mass consumption of margarine and hydrogenated vegetable fats. Until the moment when cholesterol and sugar (along with tobacco) were recognized as the main "villains" remained less than half a century.
The electrocardiography technique, used as the basis of all cardiographs, was implemented more than a century ago by the Nobel Prize in Physiology and Medicine, V. Einthoven. Its principle is as follows: the work of the heart muscle produces electric fields, as a result, galvanic currents propagate across the surface of the human body, which the device registers. This basic procedure is still successfully used to diagnose the functioning of the heart.
The first serial cardiograph appeared in 1911. What was this progenitor of the Cambridge Scientific Instrument Company cardiographs? In size and weight, he competed with a milling machine. Recording was carried out through a projection optical recorder on photosensitive paper (tape). The electrodes for the three standard leads served as a bath filled with saline.
The evolution of cardiographs went in two directions: an increase in the accuracy of reading, ease of fixation and reduction in size, portability.
In 1942, Golderberg and Wilson suggested adding three more leads to the cardiograph - unipolar and reinforced. These leads are used when standard connections for diagnosis are not enough. A similar design in the ECG apparatus is still used.
In the 1950s, the cardiograph was equipped with a tube amplifier, a compact recorder on roll paper with an ink pen, and external patch electrodes. The device became portable, but its weight still reached ten kilograms.
Portable heart monitor company Allen Electric Equipment Company, was sold in the 50s of the last century
In 1959, American engineer N. Holter invented a portable cardiograph design. The mechanism was packed in a small suitcase up to 2 kg in weight. The recording of the testimony of the device could be conducted not in the doctor’s office, but where the patient himself is at this time. Thus began the era of portable cardiographs.
Holter Monitor, 1959
The implementation of this idea in the years 1960-1970 helped the use of semiconductor components. The cardiograph has become a truly portable device. Its size and weight were on par with the encyclopedia paper volume. The device received battery power, and the resistance to external factors and reliability increased so much that the Tour Heyerdahl satellite, the doctor and traveler Yuri Senkevich, repeatedly took the domestic electrocardiograph with him on the expedition and gave him a high rating. It was the revolutionary single-channel model EK1T-03M of 1976, which later visited the North Pole.
Portable Cardiograph EK1T-03M
Over the past few decades, the dimensions of cardiographs have significantly decreased, instruments have become multichannel and more secure for patients. They were equipped with automatic cardiogram analysis functions, compact thermal printers and interfaces for data exchange with computers. But the idea remained the same: the device used a set of wires with body electrodes for galvanic detection of potential difference.
In the world of cardiographs, there is professional medical equipment and devices for primary, pre-medical diagnostics. The latter can be in the form of special disposable stickers that are placed in the heart area, or flash drives with a USB port or bracelets with wireless accelerometer sensors that respond to heartbeats. That is all that belongs to the category of wearable devices.
For all cardiographs there is one problem. Alternating current from the skin surface contains a lot of noise. The device can display a non-normalized “contribution” of muscle, vascular, skin conduction, static electricity, electrode polarization, composition of physiological electrolytes, and so on. In the case of professional equipment, the task of saving time and accurate diagnosis is solved by using multi-channel cardiographs. But for portable devices, the problem of "noise" can be solved.
You can get rid of "intermediaries" by direct measurement of the alternating electric field of the heart. The idea itself is over 20 years old. The easiest option is to use the antenna effect on high-impedance inputs of operational amplifiers. But its practical implementation until recently was impossible due to the lack of a suitable hardware solution.
We needed an industrial compact sensor, matched in amplitude and frequency band with biopotentials, capable of reproducing an alternating electric field in the form of a current or voltage signal and providing effective galvanic isolation of the patient and recording device.
Since 2012, the British company Plessey Semiconductors has been producing such sensitive elements. Depending on the purpose of diagnosis and the conditions of use, the sensors differ in power consumption, bandwidth and gain. An EPIC sensor captures changes in an electric field just as a magnetometer detects changes in a magnetic field. In general, an EPIC sensor does not require physical contact with the body to register electrical potential.
Epic Sensor
Doctors and medical equipment manufacturers have appreciated the novelty. Several serial cardiographs using the EPIC series sensors have already appeared. In Russia, the first domestic development of a full cycle based on this technology has already been launched. About this below.
In the scientific community, portable wearable devices and medical diagnostics devices from “innovators” are viewed with suspicion. Everyone remembers the recent history with Theranos , which has collected billions of dollars for a revolutionary decision to conduct independent blood tests. It turned out that the company actually does not have its own equipment, and out of 120 initially declared analyzes, in a few years only one was certified (for herpes). "Secret development" was not scientifically proven, and the quality of analysis was inferior to traditional.
Such examples of "medical gadgets" harm the reputation of responsible manufacturers with their own research base. For example, the CardioQVARK device provides diagnostic quality data. It is protected by a number of international patents and state registration certificates. According to the creators of the project, the device is currently being tested to obtain a registration certificate for a medical product.
CardioQVARK looks like a 58 g iPhone case with two EPIC sensors on the outside, a standard Apple Lightning connector on the inside for connecting to the phone, a MicroUSB connector for connecting to an external device. The ECG is recorded in it according to standard lead I. To carry out the procedure, it is enough to put fingers on the electrodes and run the corresponding application on the smartphone screen.
Cardiogram removal using a mobile cardiograph
In the case of sensors, in contrast to the classic metal electrodes, the contact force (pressure) does not matter. The quality of the result ensures the completeness and uniformity of overlap of the sensor with your finger.
Cardio Card Qualification, image source: The Secret of the Firm
It takes 20 seconds to read the complete information. After that, these data are displayed on the smartphone screen and, if there is a connection to the network, are sent to the “cloud”. The doctor also through the application receives address access to the patient's ECG stored in a single database and monitors changes in the indicators in real time. Thanks to specially developed data processing algorithms, a physician can easily see the dynamics of various indicators and promptly warn the patient about the presence of pathologies and degradations.
There are other mobile cardiographs - for example, in the United States, the AliveCor project is actively developing, which has already received a certificate from the Food and Drug Administration of the United States, which is very difficult:
Both projects have already been covered in the press and at Geektimes . In historical and technological terms, such devices are currently at the top of evolution.
They are the next step in the development of medical technology, opening up wide opportunities for remote health monitoring, diagnostics of the condition and prompt preventive monitoring of the human cardiovascular system. And the simplicity and efficiency of use and modern technological developments underlying the entire system allow such devices to become one of the basic elements for creating a national mHealth cardiomonitoring system.
Evolution of electrocardiographs in the 20-21 centuries: a) Cambridge Scienti Instrument Company, 1910-1911; b) Sanborn Cardiette Model 51, 1939; c) EK1T-03M, 1976; d) Contec ECG80A, 2012
Health economics
Health and safety are basic needs. Health is our primary resource. We invest it on a par with our work and skills. Naturally, I would like to know the state of this resource and understand the return it brings.
')
Today, many are beginning to understand that you need to deal with their health regularly. To restore it with our level of “free” medicine costs huge funds and the same nerves, that is, the remnants of health. This is what developed countries understand as the economy or the “industry” of health. While the Russian state is considering the object of attention of an unhealthy person, and disease prevention is reduced to an increase in excise taxes on tobacco and alcohol, we have to deal with the arrival and consumption of this resource on our own.
Doctors and Gadgets
So the facts. The main resource of the human body is the heart. Today, death rates from cardiovascular diseases in Russia are ominous . In Europe, in general, things are a little better . We can call the new pattern of behavior the familiar word "prevention." The essence of this will not change. There are two options: regular visits to the doctor, clinical examination (that is, diagnosis on professional equipment) and self-diagnosis using a modern compact device.
The first option is associated with obvious costs (time, money), but gives the result provided by the professionalism of the doctor and the level of equipment. The second option is commercial portable devices for monitoring vital signs and health. In the last decade, this market has been actively developing, but until now there have been constant discussions about the practical value around the so-called wearable devices.
If we are engaged in the economy of our health, we need a guaranteed, accurate result with a minimum of costs. Are there any professional-level devices for self-diagnostics on the market? An example of the mass distribution of portable blood pressure monitors for pressure testing answers this question in the affirmative.
On the memory of one generation, the tonometer turned from a massive carbolite canister with a mercury indicator, a rubber bulb pump and a phonendoscope into a compact automatic device equipped with built-in memory and data analysis function. Its accuracy is sufficient for the initial diagnosis.
What happens in electrocardiography? It turns out that progress in this direction is also impressive. A modern smartphone-compatible heart monitor provides clinical-quality data. But to understand how this works, you need to turn to history.
Cardiograph Evolution
Cardiology is a relatively young science. Until the beginning of the 20th century, infections were the main enemy of mankind. If the method of measurement and the first device for measuring blood pressure were invented in the middle of the 18th century by the British priest Stephen Heiles, then with cardiography I had to wait another couple of centuries.
The first statistics on cardiovascular diseases appeared in the United States with the beginning of the work of the American Heart Association in 1924. Interest in the problem has a clear historical and territorial link. It was in the 20s of the last century that North America experienced a boom in the production of sweet soft drinks. Sugar consumption jumped from 10-15 to 100 pounds per person per year (today 150 pounds). Began mass consumption of margarine and hydrogenated vegetable fats. Until the moment when cholesterol and sugar (along with tobacco) were recognized as the main "villains" remained less than half a century.
The electrocardiography technique, used as the basis of all cardiographs, was implemented more than a century ago by the Nobel Prize in Physiology and Medicine, V. Einthoven. Its principle is as follows: the work of the heart muscle produces electric fields, as a result, galvanic currents propagate across the surface of the human body, which the device registers. This basic procedure is still successfully used to diagnose the functioning of the heart.
The first serial cardiograph appeared in 1911. What was this progenitor of the Cambridge Scientific Instrument Company cardiographs? In size and weight, he competed with a milling machine. Recording was carried out through a projection optical recorder on photosensitive paper (tape). The electrodes for the three standard leads served as a bath filled with saline.
The evolution of cardiographs went in two directions: an increase in the accuracy of reading, ease of fixation and reduction in size, portability.
In 1942, Golderberg and Wilson suggested adding three more leads to the cardiograph - unipolar and reinforced. These leads are used when standard connections for diagnosis are not enough. A similar design in the ECG apparatus is still used.
In the 1950s, the cardiograph was equipped with a tube amplifier, a compact recorder on roll paper with an ink pen, and external patch electrodes. The device became portable, but its weight still reached ten kilograms.
Portable heart monitor company Allen Electric Equipment Company, was sold in the 50s of the last century
In 1959, American engineer N. Holter invented a portable cardiograph design. The mechanism was packed in a small suitcase up to 2 kg in weight. The recording of the testimony of the device could be conducted not in the doctor’s office, but where the patient himself is at this time. Thus began the era of portable cardiographs.
Holter Monitor, 1959
The implementation of this idea in the years 1960-1970 helped the use of semiconductor components. The cardiograph has become a truly portable device. Its size and weight were on par with the encyclopedia paper volume. The device received battery power, and the resistance to external factors and reliability increased so much that the Tour Heyerdahl satellite, the doctor and traveler Yuri Senkevich, repeatedly took the domestic electrocardiograph with him on the expedition and gave him a high rating. It was the revolutionary single-channel model EK1T-03M of 1976, which later visited the North Pole.
Portable Cardiograph EK1T-03M
Modern cardiographs
Over the past few decades, the dimensions of cardiographs have significantly decreased, instruments have become multichannel and more secure for patients. They were equipped with automatic cardiogram analysis functions, compact thermal printers and interfaces for data exchange with computers. But the idea remained the same: the device used a set of wires with body electrodes for galvanic detection of potential difference.
In the world of cardiographs, there is professional medical equipment and devices for primary, pre-medical diagnostics. The latter can be in the form of special disposable stickers that are placed in the heart area, or flash drives with a USB port or bracelets with wireless accelerometer sensors that respond to heartbeats. That is all that belongs to the category of wearable devices.
For all cardiographs there is one problem. Alternating current from the skin surface contains a lot of noise. The device can display a non-normalized “contribution” of muscle, vascular, skin conduction, static electricity, electrode polarization, composition of physiological electrolytes, and so on. In the case of professional equipment, the task of saving time and accurate diagnosis is solved by using multi-channel cardiographs. But for portable devices, the problem of "noise" can be solved.
You can get rid of "intermediaries" by direct measurement of the alternating electric field of the heart. The idea itself is over 20 years old. The easiest option is to use the antenna effect on high-impedance inputs of operational amplifiers. But its practical implementation until recently was impossible due to the lack of a suitable hardware solution.
We needed an industrial compact sensor, matched in amplitude and frequency band with biopotentials, capable of reproducing an alternating electric field in the form of a current or voltage signal and providing effective galvanic isolation of the patient and recording device.
Since 2012, the British company Plessey Semiconductors has been producing such sensitive elements. Depending on the purpose of diagnosis and the conditions of use, the sensors differ in power consumption, bandwidth and gain. An EPIC sensor captures changes in an electric field just as a magnetometer detects changes in a magnetic field. In general, an EPIC sensor does not require physical contact with the body to register electrical potential.
Epic Sensor
Doctors and medical equipment manufacturers have appreciated the novelty. Several serial cardiographs using the EPIC series sensors have already appeared. In Russia, the first domestic development of a full cycle based on this technology has already been launched. About this below.
The era of the iPhone: cardiograph in your pocket
In the scientific community, portable wearable devices and medical diagnostics devices from “innovators” are viewed with suspicion. Everyone remembers the recent history with Theranos , which has collected billions of dollars for a revolutionary decision to conduct independent blood tests. It turned out that the company actually does not have its own equipment, and out of 120 initially declared analyzes, in a few years only one was certified (for herpes). "Secret development" was not scientifically proven, and the quality of analysis was inferior to traditional.
Such examples of "medical gadgets" harm the reputation of responsible manufacturers with their own research base. For example, the CardioQVARK device provides diagnostic quality data. It is protected by a number of international patents and state registration certificates. According to the creators of the project, the device is currently being tested to obtain a registration certificate for a medical product.
CardioQVARK looks like a 58 g iPhone case with two EPIC sensors on the outside, a standard Apple Lightning connector on the inside for connecting to the phone, a MicroUSB connector for connecting to an external device. The ECG is recorded in it according to standard lead I. To carry out the procedure, it is enough to put fingers on the electrodes and run the corresponding application on the smartphone screen.
Cardiogram removal using a mobile cardiograph
In the case of sensors, in contrast to the classic metal electrodes, the contact force (pressure) does not matter. The quality of the result ensures the completeness and uniformity of overlap of the sensor with your finger.
Cardio Card Qualification, image source: The Secret of the Firm
It takes 20 seconds to read the complete information. After that, these data are displayed on the smartphone screen and, if there is a connection to the network, are sent to the “cloud”. The doctor also through the application receives address access to the patient's ECG stored in a single database and monitors changes in the indicators in real time. Thanks to specially developed data processing algorithms, a physician can easily see the dynamics of various indicators and promptly warn the patient about the presence of pathologies and degradations.
There are other mobile cardiographs - for example, in the United States, the AliveCor project is actively developing, which has already received a certificate from the Food and Drug Administration of the United States, which is very difficult:
Both projects have already been covered in the press and at Geektimes . In historical and technological terms, such devices are currently at the top of evolution.
They are the next step in the development of medical technology, opening up wide opportunities for remote health monitoring, diagnostics of the condition and prompt preventive monitoring of the human cardiovascular system. And the simplicity and efficiency of use and modern technological developments underlying the entire system allow such devices to become one of the basic elements for creating a national mHealth cardiomonitoring system.
Source: https://habr.com/ru/post/397665/
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