Heart

Electrical activity of the heart
The emergence of electric potentials in cardiac muscle is associated with the movement of ions across its cell membrane. The main role is played by the cations sodium and potassium. At rest, the outer surface of myocardial cells is positively charged, and the interior - in the negative. Under these conditions, the cell is polarized, and the potential difference is not detected. However, before cutting the heart muscle, it is excited at this time of changing physical and chemical properties of the cell membrane of muscle fibers, the ionic composition of extracellular and intracellular fluid, which is accompanied by the appearance of an electric current.
To heart beats rhythmically, it must have a pacemaker (a cell or group of cells of the excitable tissue capable of generating rhythmic excitation pulses that propagate to other cells) as well as the subsequent means of these pulses. The main pacemaker of the heart - sinoatrial node, a minor - atrioventricular node, transmitting the excitement of the sinoatrial brand name viagra node to the atrioventricular bundle (bundle branch block). The latter further divided accordingly ventricle to the left and right legs. After the pulse in all these ways, and the excitation of all parts of the heart electrical processes undergo a "reverse development" and "electric" state of the heart returns to its original position.
The principle of electrocardiography
Body tissues have a high electrical conductivity, which allows registration of electrical potentials of the heart from the body by applying electrodes to the outlet of its specific parts. This method is called electrocardiography.
ECG carried out using a special device - an electrocardiograph. In this case, the electrical potentials originating in the heart and perceived electrodes, amplified 600-700 times and drive the galvanometer fluctuations which are recorded as a curve on a moving belt. In clinical practice, uses 12 conventional leads of the electrodes: 6 from the upper and lower extremities, and 6 infants. They reflect the electrical activity of different parts of the heart.
ECG is a graph with the teeth.

Barb P corresponds to the excitation of the atria, the segment PQ - pulse delay between the atria and ventricles, the complex QRS - ventricular excitation, the segment ST - the period of full coverage of the excitation of the ventricles, prong T - the process of restoring the original building in myocardial cells, the segment TR - diastole (relaxation of the heart muscle ).
The order of the electrocardiographic study
ECG recording performed with the patient lying on his back, which allows for maximum relaxation of muscles after 10-15-minute rest and not earlier than 2 hours after meals. Before examining the patient undressed to the waist, legs and should be released from clothing, because the electrodes should be placed in direct contact with the skin.
Explanation ECG
For competent interpretation of ECG is necessary to know the nature of each of its teeth, spacing between teeth and teeth of a package of the cardiac cycle, as well as the nature of the relationship of the curves at different leads. Therefore, deciphering the ECG should be performed only by a person with experience of similar work.
With the ECG diagnose diseases of the heart muscle (myocarditis, coronary heart disease, hypertrophy, and myocardial infarction), evaluate the heart rate (normally 60-80 beats a minute) and can detect violations of an electrical pulse to the heart conduction system - cardiac arrhythmia. In severe arrhythmias (blockade of the third degree) is shown pacing, and in the future - implantation of an artificial pacemaker.
Variants of electrocardiographic studies
ECG - is quite simple, but informative study, which included a minimum of a survey of patients. But sometimes the diagnosis is not enough to remove a normal ECG. In this case, the doctor may find it useful to conduct functional tests or daily monitoring.
Functional tests with physical exertion or the use of special medicines can detect violations, which, for various reasons could not be detected in normal electrocardiographic study (latent failure of blood supply the heart muscle, irregular rhythm disturbances). Currently the most widely used test with measured physical load on the cycle ergometer (bike) or treadmill (treadmill).
ECG, taken Viagra is relationships tablet during the day, is called "daily monitoring" or "Holter monitoring. To this end, a miniature ECG machine with electrodes attached to the patient's body. Within days, he leads a normal life for him, but makes the blog entries where noted, all events occurred during the day. Daily monitoring allows us not only to identify transient disturbances of heart rhythm and ischemic changes, but also link them with the appearance of any events (physical activity, psychological experiences), with a time of day.
In some cases, to diagnose heart disease other than ECG doctor may order an ultrasound study - echocardiography. This method makes it possible to "see" the heart, to estimate the thickness of its walls and their ability to contract, the state of the valves and blood flow. There are other methods of heart, some of which are very complex and, therefore, conducted only in research centers.