Sinus tachycardia is increased heart rate from 90 to 150-180 per minute while maintaining the correct sinus rhythm. Sinus tachycardia is due to increased automaticity primary pacemaker – the sinoatrial node (SA-node). In perfectly healthy people, it occurs during exercise or emotional stress.
Pharmacological sinus tachycardia is caused by exposure to the sinus node of substances such as epinephrine, caffeine, alcohol, nicotine and other. Pathologic sinus tachycardia may be adequate and inadequate. Adequate reasons for sinus tachycardia are fever, anemia, hypoxemia, hypotension, hyperthyroidism, and pheochromocytoma.
Inadequate sinus tachycardia is characterized by persistent symptomatic increase in the frequency of sinus rhythm more than 100 in 1 min at rest in the waking state and with minimal exertion for 3 months or more for no apparent reason. Suggest that it is based on an increase in automaticity of sinus node pacemaker cells due to its primary lesion, which raise the tone of the sympathetic autonomic nervous system and reduce – the parasympathetic.
Inadequate sinus tachycardia is a rare and little-studied disorder that occurs predominantly in young people, mostly women. Patients concerned about persistent palpitations, shortness of breath, constant fatigue and frequent dizziness.
Since the sinus tachycardia SA-node regularly generates electrical impulses that are conducted in the usual way by the atria and ventricles, the ECG is little different from the norm, except for increased frequency of heart contractions.
Specific treatment of sinus tachycardia is required only in cases of inadequate sinus tachycardia, and often presents considerable difficulties. Despite the sometimes expressed subjective manifestations, the prognosis is usually favorable.
In contrast, sinus tachycardia, sinus bradycardia involves reducing heart rate to 59-40 per minute while maintaining regular sinus rhythm.
Sinus bradycardia is due to a decrease in automaticity SA-node. Often the main cause of sinus bradycardia is to increase vagal tone. Among healthy people, sinus bradycardia is especially often observed in athletes. In the pathology of sinus bradycardia occurs during some infections (influenza, typhoid fever), myocardial infarction (the oppression of the SA-node automatism due to ischemia), increased intracranial pressure (stimulation of the vagus nerve), etc.
The main symptoms of excessively slow heart rate: dizziness, shortness of breath, it becomes harder to do the exercises, fatigue, chest pain or feeling of trembling heart (palpitation), confusion, impairment of concentration, fainting due to low blood pressure. In others the symptoms may be absent or insignificant character, and usually perceived as a sign of age. You can get your heart rate by checking the pulse. If your heart rate is too slow or irregular, contact your doctor.
As well as in sinus tachycardia, ECG in sinus bradycardia is little different from normal, except for a rare rhythm. Choice of treatment of bradycardia depends on the reasons underlying the disease. If no symptoms, treatment is usually not indicated.
If a violation of the electrical cardiac system causes excessive decrease in heart rate, you probably need a pacemaker. Pacemaker – a device that is implanted under the skin helps regulate the heartbeat. Many people aged over 65 years, with bradycardia in need of such a device. When decrease in heart rate caused by some other problem such as hypothyroidism, or electrolyte imbalance, should eliminate this problem, which may contribute to recovery of bradycardia. If the decrease in heart rate is a consequence of medication, your doctor may recommend reducing the dose and prescribe another drug. If discontinuation is not possible, you may need a pacemaker. The objective of treatment of bradycardia is to increase the heart rate to the level necessary for adequate blood supply to your body. Not cured in time bradycardia may lead to serious consequences, such as fainting and injury from fainting.