Parts of the heart regularly contract and relax. First, the atrium contracts, then the ventricles. This sequence is called the heart rhythm. There are regulatory mechanisms of intracardiac rhythm at the heart. External regulation of the function of the heart is caused by the activities of the autonomic nervous system and humoral factors. Irregular heartbeat leads to the breakdown of the heart. Violations may be different: a decrease in heart rate – bradycardia, palpitations – tachycardia, impaired frequency or sequence of cuts – arrhythmia.
- Heart attacks.
- Cold sweat.
- Lack of heart rate.
Heartbeat is regulated by cardiac conduction system. Sinoatrial node generates 60-90 pulses per minute. Impulses arise in heart sinoatrial node, pass through the conduction system and cause heartbeat at regular intervals. Simultaneously, the electrical impulses that are sent by sinoatrial node, enter the atrioventricular node, and from there into a bundle branch block. Then the pulse is transferred to the muscle fibers of the ventricles, causing a reduction of the ventricles. At rest, a person has a sinus rhythm, during sleep heart beats 55-70 times per minute. Most often, heart rhythm disorder is caused by a breach formation or conduction of impulses. Rarer disorder of heart rate is due to disorders of the autonomic nervous system.
Cardiac arrhythmias may occur under the influence of alcohol, nicotine, caffeine or psychotropic substances. These substances can slow down or speed up the heart rate, leading to disruption of the heart.
Due to the strong stimulus conduction system impulse conduction disturbances can occur. As a result, the heart or parts of the heart are affected.
Tachycardia – increased heart rate (90-120-150 beats per minute.), Bradycardia – slow heart beat (20-40-60 beats per min.), arrhythmia – a chaotic contraction of the heart muscle. Temporary cardiac arrhythmias can also occur in healthy people. Bradycardia: heart rate decreases, there are momentarily disorders of consciousness. Sinus tachycardia is observed in myocarditis, heart defects, increased thyroid function. Arrhythmia is characterized by an irregular, erratic pulse. The most common form of arrhythmia: 1) extrasystole, 2) arrhythmia, which is associated with a partial atrioventricular block, 3) atrial fibrillation.
Extrasystole – frequent irregular heartbeat, which consists in reducing premature heart or parts of it. Extrasystole may occur under the influence of certain drugs, under stress, fear, etc. In addition, extrasystoles can be a sign of increased thyroid function, heart defects, or calcification of the coronary vessels of the heart.
Ventricular flutter – a dangerous abnormal heart rhythm. It’s characterized by a sudden onset and irregular reduction of individual fibers of the heart muscle. Ventricular flutter is the last stage of many diseases of the heart, such as myocardial infarction. This condition is life threatening.
If due to some reason the transfer of pulses is interrupted or slowed down, then, first of all, the sequence of heartbeat is broken (pulse are blocked). The blockade is classified according to which part of the conduction system is damaged: sinoatrial block (in the atria), atrioventricular block (in the atrioventricular node, also called atrioventricular blockade) and the blockade of the ventricles (bundle branch block). Blockade may be varying degrees of severity. The most often cause of the blockade is an overdose of drugs (some drugs are used for the treatment of heart disease, such as glycosides), and the effects of rheumatic myocarditis or other disease, which is characterized by the formation of scars.
If as a result of the blockade the ventricles are completely separated from the atria, then there are bouts of Stokes-Adams – a sudden drop in blood pressure, the patient faints due to insufficient supply the brain with oxygen. The attack may last only a few seconds, but the result is a disturbance of the heart. Heart is not stopped, because after a few seconds ventricles begin to contract. However, a complete atrioventricular block is life threatening. The causes of atrioventricular block are varied, such as calcification of the coronary vessels of the heart, as well as inflammatory processes in the body.
In blocking the propagation of pulses in the ventricles atrioventricular block begins. In this case, the bundle of His, and nerve fibers are affected.
In violation of the heart rate antiarrhythmic drugs are usually prescribed. In severe cases, the pacemaker is implanted to the patient. Pacemaker is an electrical device that is implanted under the skin of the patient and is connected by the electrodes to the heart. This device sends impulses to stimulate the heartbeat. Modern pacemakers are programmed in such a way that in increasing in physical activity they are automatically accelerated heart rhythm (eg, climbing stairs). A doctor can have control over the performance of the pacemaker by the monitoring device. At the set time the battery of the pacemaker must be changed.
People with pacemakers should avoid electromagnetic fields that can change the pacemaker, as it can be life-threatening. For example, these people can not be checked with hand-held or stationary metal detectors.
Due to the fact that cardiac arrhythmias can be life-threatening, with symptoms you should see a doctor. The first symptoms of cardiac arrhythmias: a sense of slowing or tachycardia, palpitations in the absence of physical activity, as well as dizziness, nausea, or chills.
Doctor determines irregular heartbeat on: the patient’s heart rate, using a stethoscope, listening to the heart, and by percussion upper torso.