People has long been concerned about the heart disease, as it has been long seen rapid death of man after the appearance of chest pain on the left. Many scientists were finding ways of instrumental diagnosis of heart disease. Only electrophysics achievements made possible the creation of pioneer methods of the heart functions recording. A technological breakthrough in many fields of science allowed to create new instruments for the diagnosis of various diseases, including cardiovascular diseases. Below is an overview of some instrumental methods of diagnosis of heart disease that were used in the last century, and are routinely used nowadays.
Electrocardiography (ECG) is an objective method for detecting the potential difference of beating heart. For most ordinary people the term "electrocardiogram" is more familiar. It is a record or display of a person’s heartbeat produced by electrocardiography. That is the graphic representation of the body surface potential differences arising from its functioning, by registering average of all vectors of action potentials that occur in certain moment of the heart functioning.
The familiar image of the ECG with characteristic teeth and intervals, as well as its name, is associated with the name of Willem Einthoven, which created more advanced ECG device. In 1924, he was awarded the Nobel Prize in Medicine for his discovery.
Currently, the ECG is one of the reference methods for studying the heart. International benchmark is the ECG in 12 standard leads: three standard (I, II, III), three unipolar augmented limb leads (aVL, aVR, aVF) and six pericordal augmented unipolar leads (V1 - V6). If necessary, use Nebb’s lead (D, A, J). dorsal leads (V7, V8, V9), Frank’s leads (X, Y, Z), Evans’ leads (R0), Link, Lewis, CS, esophageal, intracavitary leads. Normal ECG presented six teeth (P, Q, R, S, T, U), consists of three segments (PTa, ST, TP), four intervals (PQ, QT, RR, PP), junction point (j-point), and one complex (QRS). Thus, rather a lot of specific information is necessary for the ECG recording method.
Electrocardiography is rather simple to use and evaluate the results. That is why ECG is the screening instrumental study of heart disease. It is possible to identify signs of myocardial ischemia, both fresh and earlier heart attack. There are peculiar pattern of rhythm disturbances, signs of hypertension, heart failure.
Electrocardiography - a remarkably simple method of diagnosis, but it is necessary to pay attention to the following points:
Phonocardiography (PCG) is a graphic recording of sound phenomena arising during contraction of the heart in health and organic diseases. This study is carried out in a special cabinet with perfect sound and electrical insulation. To record PCG use standard points: M1 - over the top of the heart, M2 - in the projection of the mitral valve, T - in the area of the tricuspid valve, A - the aorta, L - the pulmonary artery, O - sixth (fifth) intercostal space on anterior muscle line ( for the differential diagnosis of stenosis and insufficiency). Low-, medium-, and high-frequency noises are recorded by the frequency response. PCG and ECG are recorded synchronously. This is necessary for the ratio of the recorded noise, tones, extratones to systole and diastole, which is of great diagnostic value.
Different pathologies can be diagnosed with PCG: myocarditis, myocardial infarction, stenosis or valvular heart disease, coarctation of aorta, pulmonary hypertension, atrial septal defect, etc.
The disadvantages include the PCG special conditions:
Echocardiography is a method of ultrasound examination of the heart. Introduction of echoscopic technology in medicine, and the improvement of ultrasonic sensors made possible the use of ultrasound in the evaluation of the functional and morphological state of the myocardium, valvular, heart shirts, tumors and other echocardiography based on the different ultrasound reflecting from tissues of different densities (myocardium, the valve apparatus, scar tissue, fluid). On the earlier devices, and in most cases at present, the research carried out in the B-mode. Modern devices of expert class with powerful computer software can under appropriate conditions to perform 3D-, and 4D-modeling of myocardial lesions.
EchoGC can get information about:
Echocardiography is used for the diagnosis of various cardiovascular diseases: heart disease, heart attack, aneurysm, cardiac arrhythmias, hypertension, pulmonary artery and its small branches, growths of vegetation on the valves, etc.
The disadvantages of this method are:
Holter monitoring (HM) refers to methods of functional diagnosis of the heart muscle functioning. Holter monitoring has been used for the identification of cardiac arrhythmias, ischemia, monitoring drug therapy (antiarrhythmic and antiangianal).
The appearance of this new study is obliged Norman Holter (1961), who suggested joining ECG and the possibility of transmission by radio. With the improvement of technology HM decreased weight of the machine to record the potential difference of the heart, and increased the time of recording the signal, reduced signal distortion artifacts, the processing and analysis of the signals became faster. The continuous 24 hours HM with ECG recording became possible.
Disadvantages of this method:
Coronary angiography (CAG) is a type of X-ray examination based on the injection of contrast substance in the coronary vessels. It is based on angiography - the study of human vasculature using an X-ray machine. At the same time, the long catheter is inserted through the femoral artery or an artery in the forearm in the artery with a special tool (introducer), the beginning of which is supplied to the coronary vessels examined, controlled by fluoroscopy. After this, the contrast substance is injected, and coronary stenosis, tortuosity of vessels, the reaction to myocardial contractions, etc., become visible. You can build with the software three-dimensional coronary vessels, which facilitates heart surgeon navigation before the surgery. In addition, the method can conduct minimally invasive treatment - performance of balloon dilation (expansion) of the narrowed area or staging stent.
К недостаткам КАГ можно отнести: специальные условия (только стационар) и наличие дорогостоящего специального оборудования, инвазивность процедуры с соответствующими осложнениями, лучевая нагрузка и необходимость подготовки соответствующих специалистов, возможность миграции катетера. Кроме этого, имеется ряд противопоказаний:
К тому же, во время выполнения ангиографического исследования может наступить остановка сердечной деятельности, что потребует проведения реанимационных мероприятий.
The disadvantages of CAG are: special conditions (only hospital) and the availability of expensive special equipment, invasive procedures with relevant complications, radiation exposure and the need for training of specialists, the possibility of migration of the catheter. In addition, there are a number of contraindications:
In addition, cardiac arrest is possible during the angiographic study, which requires resuscitation.
Intravascular ultrasound (IVUS) is a new way to visualize blood vessels including coronary, which became possible due to technological progress. The fundamentals of IVUS is the use of microscopic ultrasonic sensors on catheters that are introduced into the lumen of the vessel. This study allows estimation of stenosis degree, the structure of the atherosclerotic plaque, the control of the disclosure of coronary stent, restenosis assessment, etc.
The disadvantages listed in CT angiography, in this case, you can also include the cost of catheters with ultrasound sensors, which limits their widespread applying.
Cardiovisor in clinic is a screening device that allows to screen the patients for healthy and sick. Cardiovisor is also a good tool in the clinic to monitor the dynamics before and after the treatment of the heart.
Home Cardiovisor it's a great opportunity for any patient to perform self-control of one's heart functioning. Patient is self-examined, and instantly obtains the simple, clear conclusion. The examined patient no need to go outdoors to send the results to his doctor for control. The method relies on the recording and analysis of variance ECG mapping and analysis of microalternations that reflect electrophysiological state of cardiomyocytes. This technology allows you to assess the state of the myocardium in more range than ECG. This takes into account the nature of the perfusion, changing of the microcirculation and metabolism in heart muscle at rest, and load and medication, allowing to assess not only the state but also to be aware of the functional reserve of the myocardium..
The device consists of 4-electrode unit that connects via USB to any computer with free internet access. Each patient has a personal account on the site Kardi.ru, where previous studies are stored. The information is displayed for the patient on a computer screen in a minute from the start of the study as a series of three-dimensional graphics cards of right and left chambers of the heart, allowing visually assess the state of the heart, clearly commented in text form. The study process is simple, takes up to 30 seconds, can be performed if you have pain. It does not require special training, expensive consumables, no need to remember "where my cardiogram" before going to the doctor. The device is compact, low weight, and easy to use.
Every year the modern technologies are moving forward. In the medical field there are new devices, often with more than one non-traditional approach in the diagnosis of disease. But at the same time they provide new perspective of appliance, and give way for new inventions.