Arrhythmias are called various violations of frequency, rhythm and sequence of contractions of the heart.
In a healthy person in a state of physical and emotional rest heart rate normally ranges from 60 to 90 for 1 minute. At the same time intervals between beats are practically constant.
During exercise, an increase in heart rate (physiological tachycardia), while maintaining the proper rhythm. Such a reaction is observed when emotional stress, being a normal reaction of the heart to the activation of the nervous system. At the same time, the heart rate can also decrease under certain physiological conditions. This phenomenon is called functional or physiological aetiology and occurs in physically trained individuals.
During sleep, under the influence of physiological changes in autonomic regulation, is also a slow heart beat. It is also considered normal.
Under the arrhythmia is usually described as pathological changes in the frequency and heart rate that can occur at loads as well as at rest.