Tachycardia - Causes, symptoms and treatment. MF.

Causes of tachycardia
Symptoms of tachycardia
Diagnosis
Treatment of tachycardia
Lifestyle, complications and prognosis

The correct rhythm of cardiac contractions is provided by conducting electrical signals through a conducting system to muscle cells directly providing atrial and ventricular contraction. The conductive system includes a sinus node in the right atrium, an atrioventricular node between the atria and ventricles, a bundle of Gis in the thickness of the septum between the left and right ventricles and Purkinje fibers in the ventricular muscular wall. The normal rhythm is set in the sinus node, spreading evenly down, and is performed at a frequency of 60 to 80 beats per minute. The heart rhythm is maintained not only by the ability of the heart to automatism( independent generation of impulses), but also through neurohumoral regulation, that is, the balancing effect on the cardiac muscle of the autonomic nervous system( sympathetic and parasympathetic) and chemicals( mediators)endings with cells of the conduction system or with muscle cells. Also, the hormones of the adrenal glands( adrenaline, norepinephrine) and the thyroid gland( T3, T4) affect the contraction of the cardiac muscle.

If the influence of the sympathetic nervous system causing an increase in the heart rate is prevalent, and also if the hormone in the body is acting on the heart muscle, toxic agents or it is affected by pathological processes( inflammation, scarring), then there is an acceleration of the heart rhythm calledtachycardia. The mechanism of development is associated either with a direct effect on the frequency of contractions of these substances, or with the formation of a re-entry of the excitation wave, when, when further fibers are blocked, the pulse returns back and stimulates the already contracted fibers, that is, the intact fibers have more impulses than necessary. So there is an ectopic focus of excitement.

Tachycardia is a symptom that can accompany many cardiological and noncardiological diseases, and is characterized by an increase in heart rate of more than 90 beats per minute while maintaining a regular regular rhythm when the atria and ventricles are contracted, albeit often, but at the same frequency.

The following types of tachycardia are distinguished:

1. Physiological and pathological.
2. Sinus and ectopic.

Sinus originates from the sinus node, ectopic - from the ectopic focus of excitation( located not in the sinus node).

Ectopic is divided into:

- atrial tachycardia - focus of excitation in the walls of the atria,
- nodal( atrioventricular) - the function of the initial pulse generation takes on the atrioventricular node, becoming the rhythm driver instead of the sinus node, and the excitation spreads not only downwards,, but also upwards on the atrium,
- ventricular - the focus of excitation in the walls of the ventricles.

Nadzheludochkovye, in a different way supraventricular( atrial and nodal) and ventricular tachycardia can be paroxysmal and non-paroxysmal( accelerated).The differences between these two forms manifest clinically on the ECG and will be described below.

Causes of tachycardia

Sinus tachycardia may be a variant of normal in healthy individuals and appear with physical activity, stress, coffee and nicotine. Such a tachycardia is considered physiological. Pathological sinus tachycardia is considered if the following diseases have caused it:

1. Organic cardiac pathology:
- myocarditis
- cardiomyopathies, myocardial dystrophy
- ischemic heart disease
- acute myocardial infarction, postinfarction cardiosclerosis
- heart defects
- bacterial endocarditis
- rheumatic carditis
- pericarditis
- chronic heart failure
2. Endocrine disorders
- pheochromocytoma( adrenal medulla tumor)
- thyrotoxicosis( increased thyroid hormone production)
3. Neurogenic diseases
- neuroses
- neurasthenia
- neurocirculatory dystonia
4. Intoxication of the body
- chronic alcohol use
- fever
- sepsis( blood infection)
- tuberculosis
- overdose of drugs - cardiac glycosides, antiarrhythmic drugs capable of exerting proarhythmogenic effectcapable of causing disturbances in the rhythm - propafenone, quinidine, etmozin), beta-adrenomimetics in bronchial asthma( salbutomol, berodual, fenoterol)
5. Other causes - lowershock and collapse, acute pain syndrome

Nadzheludochkovaya tachycardia ( atrial and nodal forms) is most often caused by endocrine, neurogenic diseases described above, as well as intoxication of the body, hypertension, heart defects, in children can develop with Wolff syndrome- Parkinson's - White( ERW - syndrome).

Ventricular tachycardia , especially paroxysmal, is a prognostically less favorable form, as it can lead to ventricular fibrillation and cardiac arrest. As a rule, it is caused by severe organic heart diseases, listed above.

Symptoms of tachycardia

Sinus tachycardia is characterized by an increase in heart rate of more than 90 beats per minute, reaching 150, rarely 180 per minute. In most cases, the patient tolerates well, without causing unpleasant sensations in the heart. This is especially true for people with a lack of cardiac diseases. In the case of organic damage to the heart tissue, tachycardia can be manifested by attacks of rapid heartbeat, fatigue, especially with exercise, symptoms of the underlying disease( dyspnea, pain in the heart, dizziness, etc.). If the pulse is constantly more than a hundred per minute, even at rest, and all the more accompanied by severe discomfort( a sensation of severe strokes in the chest, a feeling of stopping, heart sinking, chest pain, loss of consciousness), you need to see a doctor to eliminate organic diseasesHeart, which caused sinus tachycardia.

Nadzheludochkovye tachycardias ( atrial and atrioventricular) can be paroxysmal and non-paroxysmal. Paroxysmus means a suddenly developed and suddenly-onset tachycardia attack lasting from a few seconds to several days and characterized by an increase in heart rate to 140-250 beats per minute. As a rule, the patient can clearly indicate the beginning and the end of the attack, manifested by a pronounced palpitation, pain and discomfort in the heart, difficulty breathing, dizziness, anxiety or panic, reduced blood pressure. The patient may lose consciousness.

Ventricular tachycardia can also be paroxysmal and non-paroxysmal. With paroxysm suddenly develops rapid heart rate with a frequency of 140 - 220 beats per minute, accompanied by pressing pains in the neck and chest, sweating, weakness, shortness of breath, pressure decrease. There may be a fainting condition, neurological symptoms( short-term paresis of limbs, visual impairment, speech).If ventricular tachycardia develops against a background of acute myocardial infarction, it can cause cardiogenic shock, pulmonary edema. The frequency of seizures varies from several short runs( three to four ventricular complexes per ECG) per minute to one attack in a lifetime. If the seizures are repeated very often, and the patient does not receive proper treatment, it can lead to ventricular fibrillation and death. Therefore, with paroxysm, which occurred for the first time in life, or with frequently recurring paroxysms, you should consult a doctor to determine the cause and purpose of treatment, especially if the previous therapy is ineffective in .

Non-paroxysmal forms of supraventricular and ventricular tachycardia ( accelerated ectopic rhythms) differ in high, but lower than in paroxysms, heart rate, reaching a maximum of 120-130 beats per minute. Thanks to this, tachycardia is much more easily tolerated by the patient, and the beginning and end of the rapidity of the rhythm is not always noticeable. On the foreground are complaints related to the underlying heart disease. Develops with pronounced organic changes in the heart muscle. By duration, this type of tachycardia can be from a few minutes to several days and even months.

Diagnosis of tachycardia

The presence of tachycardia can be assumed on the basis of complaints and the patient's medical history, but in order to determine what type of tachycardia it is, it is necessary to perform electrocardiography and, possibly, a fuller examination if the doctor deems it necessary.
So, the following diagnostic methods can be assigned:

1. ECG.When performing a single ECG at rest, signs such as:
can be registered with sinus tachycardia( often detected by chance, without complaints of frequent heartbeats) - an increase in heart rate within 90-150( 180) beats per minute, rhythm sinusoidal, correct, P wave positive.
- with nadzheludochkovyh tachycardia - heart rate 140 - 250 per minute, the ventricular QRS complex remains normal, the P wave in atrial tachycardia can be negative, biphasic( +/-) or deformed, located before the QRS complex, with atrioventricular tachycardia negative, located afterQRS complex( normally, when the rhythm driver is a sinus node, it should be located in front of it)
- with ventricular tachycardia - HR of 140 - 220 per minute, QRS complex is deformed, enlarged more than 0.12 s, atrioventricular arisesI dissociate - ventricles at their own pace and in its atrium. Possible posttahicardial syndrome - negative T wave and ST segment depression for some time after the attack of tachycardia( signs of myocardial ischemia due to the sharply increased myocardial oxygen demand)
- with non-paroxysmal forms of supraventricular and ventricular tachycardia - the signs are the same, but not withsuch a high frequency, remaining in the range of 120 to 130 per minute.

The pictures show ECG with different types of tachycardia:

Normal ECG

Sinus tachycardia

Nadzheludochkovaya tachycardia

Ventricular tachycardia

2. Daily monitoring of ECG by Holter is mandatory for the study of patients who complain about cardiac disruptions, as well as for persons with organic pathologyheart. Allows to register occurrence of attacks of a tachycardia within day.
3. The ultrasound of the heart is used to confirm or exclude the cardiac pathology, which was the cause of tachycardia. Has prognostic value in determining the function of the left ventricle - ejection fraction, stroke volume( see below)
4. EFI - electrophysiological examination of the heart( esophagus or endocardial - intracardiac) may be prescribed to clarify the location of the ectopic focus( topical diagnosis)if other methods of diagnosis are less informative
5. Samples with a load( treadmill test, veloergometry) with sinus and supraventricular tachycardia are used to identify the connection with nagand assessment of tolerance for it. When ventricular tachycardia should be used with caution, and only if the patient indicates that it is the load that triggers the onset of an attack of tachycardia. The cabinet should be equipped with a kit for resuscitation, since ventricular tachycardia can lead to ventricular fibrillation and asystole( cardiac arrest).
6. MRI or MSCT of the heart is used to determine the localization, volume and nature of the pathological focus in the cardiac tissue, if there is an

. In addition to the instrumental, laboratory tests are performed:
- general blood and urine tests
- biochemical blood test( liver, kidney function, glucose level, lipid spectrum, etc.)
- hormonal studies in case of suspected pathology of the thyroid gland, adrenal gland, diabetes mellitus
- immunological studies, rheumatological testss for autoimmune diseases, rheumatic heart diseases

An individual examination plan will be appointed by the attending physician at full-time admission, self-diagnosis if complaints about heart palpitations are not available.

Treatment of tachycardia

Sinus tachycardia , which occurs in patients without organic damage to the heart and does not cause significant discomfort, does not require treatment. In the case of a tachycardia of a neurogenic nature, a consultation of a neurologist with the use of sedative drugs( motherwort, valerian, St. John's wort, sage, psychotropic drugs) is required. If the patient has a major disease that causes tachycardia( cardiac or endocrine disease, alcoholism, sepsis, etc.), treatment is required first of all for this pathology. Therapy itself tachycardia is reduced to the appointment of beta - adrenoblockers( prandolol, carvedilol, etc.) or calcium channel blockers( verapamil, diltiazem).
The doctor can teach the patient to use vagal tests on his own if there are symptoms of tachycardia - Valsalva test( straining with deep inspiration), Aschner( pressing on closed eyed apples in a prone position), face wrapping with ice slices or wiping with cold water, an inspiration attempt with a closed glottis, causing an emetic or cough reflex. As a rule, carrying out these measures within 30 seconds allows us to overcome unpleasant symptoms due to a reflex slowing of the frequency of cardiac contractions.
In case of ineffectiveness of the therapy, presence of severe clinical manifestations and concomitant severe pathology, cardiosurgical treatment - radiofrequency ablation of the pulmonary veins mouth or implantation of the pacemaker( artificial pacemaker) may be indicated by indications.

Attack of the supraventricular tachycardia itself can also be attempted to stop using vagal samples. If this type of tachycardia is already established earlier to the patient, the symptoms are not significant, and there are no hemodynamic disturbances, then it is enough to visit the attending physician in the clinic with correction of the treatment if necessary.
If the attack of rapid heartbeat has developed for the first time in life, that is, the patient does not yet know what is his type of tachycardia, and even more so if there are significant pains in the heart, suffocation, hemodynamic disorders( sharp decrease in blood pressure, loss of consciousness), thenImmediately call an ambulance. In this case, hospitalization in a hospital with a therapeutic and diagnostic purpose is indicated.
Therapy of this type of tachycardia consists in the administration of beta-blockers, calcium channel antagonists and antiarrhythmics in the form of tablets or intravenously( inpatient).Of the antiarrhythmics, novocainamide( intravenously), sotalol, etatsizin, allapinin, aymalin, etc. are used. Amiodarone is rarely used.
In the absence of the effect of therapy, the same surgical methods of treatment as in sinus tachycardia can be used.

Ventricular tachycardia is more dangerous for the patient's life, so the seizure must be performed in the hospital. Intravenous infusion is performed for at least 24 hours, if it was possible to stop the attack with preparations of antiarrhythmics - lidocaine, novocainamide, amiodarone. If the attack does not stop, and if there are signs of shock( pressure below 80 mmHg, threadlike pulse, pale and cyanotic skin, absence of urine through the catheter) in the intensive care unit, the patient undergoes cardioversion, that is, through the heart of the patient a certain current, to "restart" the heart and give him the right rhythm.
After a successful recovery of the rhythm and discharge from the hospital, the patient must indefinitely take beta-blockers and antiarrhythmics.
If a patient suffers from a persistent form of ventricular tachycardia, frequent seizures, if he has suffered clinical death or frequent fainting as a result of paroxysms, he may be advised to perform radiofrequency ablation, implantation of a pacemaker( cardioverter-defibrillator), or aneurysmectomy( excision of the left ventricular aneurysm of the postinfarctionparoxysms).

Lifestyle with tachycardia

Patients with sinus tachycardia in the absence of organic heart disease do not need to restrict physical activity, it is enough to observe a healthy lifestyle and eat right. It is necessary to limit the amount of alcohol consumed and smoking.

With supraventricular tachycardia, which is subjectively well tolerated, it is also allowed to lead a habitual lifestyle with the limitation of provoking factors( stresses, sports, smoking, alcohol).

Any type of tachycardia, especially ventricular, in combination with heart disease, requires a more thorough approach to the organization of a lifestyle. This concept includes:

- adherence to the principles of rational nutrition - the exclusion of fatty, salty, spicy foods, the use of cereals and cereals, lactic products, low-fat meat, fish and poultry, natural juices, vegetables and fruits.
- observance of the work and rest regime with the restriction of significant psycho-emotional and physical exertion, long stay in the open air.
- adherence to treatment is the key to preventing frequent seizures and complications. It is necessary to visit a doctor in time with additional methods of research, regularly take antiarrhythmic drugs and other medications prescribed by a doctor for other heart diseases.

Complications of tachycardia

Complications with sinus and supraventricular tachycardia develop rarely. With paroxysm of ventricular tachycardia, arrhythmogenic shock, acute heart failure, pulmonary edema, ventricular fibrillation, asystole and clinical death can develop. Prevention of complications is the regular use of antiarrhythmic drugs that reduce the heart rate.

Prognosis

Sinus and supraventricular tachycardia are more prognostically favorable than ventricular tachycardia. The prognosis for the latter is determined by the nature of the underlying disease. For example, with successful surgical correction of heart defects and slow development of heart failure, the prognosis is favorable, and with extensive acute myocardial infarction with the ventricular tachycardia that has arisen against it, unfavorable. Also the prognosis depends on whether the function of the left ventricle is preserved. If the ejection fraction by ultrasound of the heart is within the normal range( 60% or more), the risk of developing cardiac death is less than with a low ejection fraction, since a normally functioning ventricle is less prone to arrhythmogenic factors. Given the constant intake of antiarrhythmics in combination with beta - blockers, the risk of cardiac death is significantly reduced.

Doctor therapist Sazykina O.Yu.