the main
about the project
Medicine news
To authors
Licensed books on medicine
<< Ahead Next >>

Disruption of automatism

Nomotopic rhythm disturbances. Sinus arrhythmia is manifested in recurrent increases and decreases in heart rate. Patients do not complain. Sinus arrhythmia is often associated with the phases of respiration, can occur in healthy children. Respiratory arrhythmia occurs when the inspiratory heart rate increases and the exhalation heart rate decreases. It is caused on the inhale by a reflex decrease in the tone of the vagus nerve, on the exhale by an increase in the tone of the vagus. On ECG, a change in heart rhythms (R-R or P-P intervals of various durations due to an increase in diastolic T-P intervals).

Sinus bradycardia - a decrease in the number of heartbeats. It is due to the increased influence on the sinus node of the parasympathetic nervous system or a decrease in the influence of the sympathetic nervous system. It occurs in healthy children-athletes, with vascular dystonia of vagotonic type, with rheumatism, hypothyroidism, traumatic brain injury, brain tumors, some infectious diseases. Patients do not complain. On the ECG, the atrial and ventricular complexes are not changed, the interal RR (cardiac cycle), T – P (heart diastole) are extended, the duration of the interval P — Q is slightly increased.

Sinus tachycardia - an increase in the number of heartbeats. Associated with the impact on the sinus node of biologically active substances that increase its excitability, or an increase in the tone of the sympathetic nervous system, or a decrease in the tone of the vagal nerve. There is sinus tachycardia with physical and emotional stress, fever, organic heart disease, various infections and intoxications, thyrotoxicosis. On the ECG, the atrial and ventricular complexes are not changed, the inteval R — R (cardiac cycle), T — P (diastole of the heart) are shortened.

Heterotopic rhythm disturbances. Nodal rhythm - an increase in the automatic function of the atrioventricular node and a decrease in the automatic ability of the sinus node due to functional or organic changes. Complaints do not show, sometimes complaints of a pulsation in the neck, which is noted while reducing the atria and ventricles. When auscultation of the heart is determined by the gain of 1 tone. On an ECG - the negative tooth P precedes the QRS complex, the interval R - R is shortened.

A periodic change in rhythm from the sinus to the atrioventricular node is observed. In this case, the heart is excited under the influence of impulses emanating alternately from the sinus node, then from the atrial conductive system, then from the atrioventricular junction, and the pacemaker migrates again in the same sequence. No complaints, no objective changes. The clinical picture is reduced to the underlying disease (rheumatism, intoxication). On the ECG, the shape, amplitude, position of the P wave, as well as the duration of the interval P — Q, which, when moving to the atrioventricular node, becomes shorter, changes.

Extrasystole - premature contraction of the whole heart or its individual part, arising under the influence of an additional focus of excitation coming from the sinus node. Causes: inflammatory, dystrophic, degenerative, toxic, mechanical damage and neurogenic disorders. Depending on the place of origin, ventricular, atrial, atrioventricular are distinguished. Extrasystoles can be single, multiple, can occur after each contraction in a certain sequence (bigemia) or after two contractions (trihemia). Extrasystoles that occur in various ectopic centers are called polytopic. Complaints often do not show, sometimes there are discomfort in the heart (fading, stopping, a strong push). With auscultation of the heart, there are additional pulse beats, additional heart sounds. In atrial arrhythmia, excitement from an ectopic focus begins before monotopic arousal, and after a premature contraction of the heart, a long incomplete compensatory pause occurs. On an ECG, a deformed P wave is premature or overlaps on the previous P wave, shortening the R interval — R, the QRS complex is not changed, the T — P interval is moderately increased.

With atrioventricular extrasystoles, the impulse comes from the node of Aschoff-Tavara, extends retrograde to the atria, from the bottom up, and the excitation of the ventricles usually goes. On an ECG - a negative tooth P in a different location in relation to the QRS complex, or in front of the complex, or merges with it, or goes after it, the shape of the QRS complex is not changed, the interval T - P is equal to two normal heartbeats (full compensatory pause).
With ventricular extrasystoles, the excitation sequence of the heart changes, the impulse arising in the ventricles does not extend retrograde, and the atria are not excited. The excitation of the ventricles is alternately and non-simultaneous, as is normal, depending on the location of the ectopic focus.

On ECG, ventricular extrasystoles appear:

1) premature occurrence of a QRS complex without a preceding P wave;

2) the QRS complex with a high voltage, is wide, split, jagged, a passing tooth of T without interval S - T;

3) discoordinate direction of the T wave relative to the maximum tooth of the QRS complex extrasystoses;

4) the lengthening of the compensatory pause after an extrasystole, the distance between two R — R intervals, including an extrasystole, is two normal cycles. There are right and left ventricular extrasystoles:

a right ventricular extrasystole in 1 assignment the largest tooth of the R complex of a QRS, extrasystoles are directed up, and in 3 assignments the S tooth, directed downwards is greatest.

In the left ventricular type in 1 lead, the largest tooth S of the complex QRS extrasystoles is directed downward; in 3 leads, the R tooth is directed upward. The origin of a functional extrasystole due to a violation of extracardiac, often autonomic, regulation.

The main signs of functional extrasystole (most often found in prepubertal and pubertal age):

1) labile during the day, changes when changing the position of the body, during exercise;

2) children show signs of vegetative dystonia, foci of chronic infection, endocrine disorders;

3) when using special methods of research, no violations of myocardial contractility are detected; clinorotostatic test, sample with metered exercise, pharmacological tests with ECG recording testify in favor of functional extrasystole. The origin of organic extrasystoles arises from the defeat of the myocardium or the cardiac conduction system. The main features of organic extrasystoles:

1) permanent;

2) the general condition is usually disturbed and there are signs of organic heart disease (rheumatism, non-rheumatic carditis, congenital heart defects).

Paroxysmal tachycardia is an attack of a sharp increase in heartbeat, 2-3 times higher than normalization of rhythm, which occurs when there is an ectopic center capable of producing high frequency impulses. Complaints in older children of discomfort in the heart, a feeling of tension in the neck, dizziness, fainting, pain in the underbelly, abdomen. In young children, paroxysmal tachycardia is accompanied by convulsive and dyspeptic symptoms. An objective examination of dyspnea, cyanosis, pulsation of the veins, congestion in the lungs, liver enlargement, pulse can not be counted, small filling, lowering blood pressure.

The atrial, atrioventricular, ventricular forms of paroxysmal tachycardia are distinguished. An ECG in atrial paroxysmal tachycardia reveals a long series of atrial extrasystoles with a sharp shortening of the interval T – P, the layering of the P wave on the T wave with its deformation, QRS complex is not changed or moderately deformed, the atrioventricular paroxysmal tachycardia is characterized by a repeated pattern and is applied by a simple pattern, and is applied and has a simple pattern, and a cross-sectional pattern is applied. , or their displacement on the QRS complex, or by merging with the T wave. The ventricular form of paroxysmal tachycardia on the ECG is a deformed, expanded complex QRS. Atrial teeth P appear regularly and layered on the ventricular complex of extrasystoles.

Atrial fibrillation is a violation of the correct activity of the atria due to the appearance in the atria of one or more foci of excitation. Complaints about the deterioration of health, a sense of fear, anxiety. During auscultation, different sonic tones, random alternation of short and long pauses, the number of ventricular contractions depends on the form of atrial fibrillation, there is a shortage of pulse (during auscultation the number of heart contractions is greater than the pulse waves). On the ECG, the P wave is absent and is slowed down by waves of various sizes and shapes. The QRS complex is not changed, the interval S — T is below the isoelectric line, the T wave and the isoelectric line are deformed by twinkling waves.

<< Ahead Next >>
= Go to tutorial content =

Disruption of automatism

  1. Rhythm disturbances associated with slow channels: dependence and automatism
    The recent discovery of the incoming ion current flowing through the membrane through the so-called slow channels has a great theoretical and practical value [76]. This current, carried mainly by calcium ions and partially by sodium ions, plays a major role in the depolarization of cells of the sinus and atrioventricular nodes. In addition, it can cause depolarization of cardiac cells
  2. Brain functions and possible disorders of these functions
    The higher brain functions include speech, gnosis and praxis. Speech function is closely related to the functions of writing and reading. Several analyzers take part in their implementation, such as visual, auditory, motor and kinesthetic. For proper performance of the function of speech, the preservation of the innervation of the muscles is necessary, first of all, of the tongue, larynx, and soft palate. Also significant
  3. Dysfunction of the nervous system caused by hereditary metabolic disorders
    Disorders of the nervous system in congenital metabolic disorders result from the influence of several factors: • direct damage to nerve cells due to the lack of any enzyme; • accumulation of certain undigested metabolic products outside the cellular fluid; • damage to other organs (eg, liver); • damage to cerebral vessels.
    CAUSE-AND-INVESTIGATION CONNECTION In accordance with the conditioned reflex teaching of I.P. Pavlov (15) and the theory of functional systems P.K. Anokhin (2,19), the function arises in response to exposure to environmental factors. Traumatic environmental factors cause pain impulses in nociceptive fibers. (23). Considering that the compression of nerve fibers can be not only in the reception area, but also in any
  5. Bowel dysfunction
    The functions of the intestine can be impaired due to many organic diseases and lead to serious changes in the functions of various organs and systems. In some cases, these disorders occur as a result of disorders of the nervous regulation of the motility of the small and large intestine and then have a rather favorable
  6. Tubular dysfunction
    Isolation of disorders associated with dysfunction of the tubules is conditional, since in functional terms the tubular system of the kidneys is closely related to the glomeruli, and pathological disorders often follow the dysfunction of the nephron as a whole, but some indicators can be regarded as the result of preferential dysfunction of the tubules. These disorders include
  7. Sexual dysfunction
    Some women, telling the doctor about their sexual problems, complain primarily about dysfunction of the genital tract. On the contrary, sexual dysfunction can be considered as a cause of discomfort in the lower abdomen or dyspareunia with organic changes in the genitals. However, more and more women seek medical help for sexual disorders,
  8. Typical disorders of gas exchange lung function.
    Are the following typical violations of gas exchange lung function? 1. Violation of alveolar ventilation? a) alveolar hypoventilation b) alveolar hyperventilation c) uneven ventilation 2. Disturbance of lung perfusion. 3. Violation of ventilation and perfusion relationships. 4. Violation of diffusion capacity of the lungs. Mixed
    Peristalsis of the large intestine was observed in all 87 patients (100%). Dysfunction of the urinary system was observed in all 87 patients -100%. Violation of thermoregulation was observed in all 87 patients -100%. Disturbance of the trophic function of the nervous system from dystrophic manifestations to bedsores always accompanies spinal injury. Dystrophic changes
    J.B. West (John V. West) The main function of the lungs is to provide gas exchange between the inhaled air and venous blood. Consequently, the usual place from which the mechanism of impairment of respiratory function begins to be considered is the alveolar membrane (see Fig. 200-1). Representing a barrier between blood and gas, it has a thickness of less than 1 micron and a surface of about 100 m,
  11. Violation of the evacuation function of the stomach
    The slowdown in the evacuation of food from the stomach is called gastroparesis. It may occur due to impaired neurohumoral regulation, pathology of the smooth muscles of the stomach, and possibly the pacemaker of the stomach (for example, due to surgical incision of the vagus nerve). The intersection of the vagus nerve usually leads to an increase in the tone of the proximal stomach with a simultaneous decrease
  12. Dysfunction of the stomach
    The stomach performs various functions in the body and their violation leads to the development of pathological processes. Disturbance of secretion of hydrochloric acid and pepsin. Hydrochloric acid is secreted by the parietal cells (layering) of the gastric mucosa, which is about 1 billion cells. Regulation of its secretion is a rather complicated mechanism, including 3 phases of secretion - mental, cephalic and
  13. Esophageal dysfunction
    The subjective feeling of difficulty passing food through the esophagus is called dysphagia and it is the leading symptom in various diseases. Dysphagia can occur with the breakdown of the passage of food at the level of the pharynx, dysfunction of the body of the esophagus and disruption of the mechanism of opening the cardia. Since the nerve centers responsible for the regulation of the act of swallowing are in the brainstem, the most
  14. Esophageal dysfunction
    The process of passing food through the esophagus is rather complicated and includes, on the one hand, the act of swallowing itself, which is provided by the throat muscles, and on the other, the subsequent transesulfage passage of the food bolus with simultaneous relaxation of the lower esophageal sphincter and the opening of the cardia. The subjective feeling of difficulty passing food through the esophagus is called dysphagia (from the Greek.
    The vegetative nervous system innervates the smooth muscles of all organs of the body, the exocrine and endocrine glands, the heart. It regulates such vital functions as respiration, blood circulation, digestion, metabolism, maintains a constant body temperature, regulates the functions associated with the continuation of the species. The autonomic nervous system is not subject to direct voluntary control, in
  16. Dysfunction of the parathyroid glands
    Hyperparathyroidism is a syndrome caused by increased function of the parathyroid glands. It occurs in parathyroid dystrophy (primary hyperparathyroidism, Recklinghausen's disease). The basis of the disease is the formation of adenomas in the parathyroid glands. Lowering calcium levels also stimulates gland function. Therefore, secondary hyperplasia and hyperfunction of these glands occur in case of primary disturbance.
  17. Tubular dysfunction
    Two processes occur in the tubules: reabsorption and secretion. Tubular reabsorption is the process of moving substances through the cells of the renal epithelium into the peri-canal extracellular space. Tubular secretion - the transport of substances from peri-tubular fluid into the lumen of the tubules. The transport of substances in the tubules is carried out actively with the participation of enzymes-carriers and energy expenditure.
  18. Higher mental functions and their disorders
    A person’s unique ability to speak and think, subject perception (gnosis) and actions with objects (praxis), as well as their disorders in focal brain lesions, have always been in the field of vision of neurologists. As the structural and functional ideas about the brain, the laws of nervous activity, the biological social nature of man, the laws of the human psyche, language improve
  19. The main manifestations of endocrine disruption
    Under the normal endocrine function refers to a level of increment, which provides the needs of the organism at any given moment of its existence in specific environmental conditions. Endocrinopathy disorders are called endocrinopathy. The following main types of endocrinopathies are distinguished (Table 1): a) Hyperfunction - an excessively high incretion inadequate to the needs of the organism;
Medical portal "MedguideBook" © 2014-2016