Atrial fibrillation - an asynchronous excitation and subsequent reduction of individual sections of the atria, resulting irregular, disorganized electrical activity of the atrial myocardium, accompanied by violation rhythmic contractions of the ventricles.
Depending on the length and type of flow arrhythmias, atrial fibrillation is divided into several forms: paroxysmal (accompanied by a complete self-leveling of symptoms within 48 hours), persistent (not possible restoration of normal rhythm of cardiac activity without medical correction) and a constant (not treatablenecessary medication).
This pathological state is the leader among all the possible forms of cardiac arrhythmias in terms of disease, which progressively increases with increasing age of the patients.Risk of morbidity from some form of atrial fibrillation are elderly people with a history of chronic cardiovascular disease, a history of the disease.
Causes of atrial fibrillation
The main factors provo
Despite considerable progress therapeutic approaches to the treatment of rheumatism, still the highest number of recorded episodes of atrial fibrillation have a rheumatic origin.In a situation where a patient has a combination of purchased rheumatic mitral defect nature and hypertension, the risk of heart rhythm disturbances by type of atrial fibrillation increases several times.
Chronic ischemic damage to the myocardium of the heart is accompanied by atrial fibrillation only in the case of heart failure, and in the case of acute ischemic attack myocardial infarction, atrial fibrillation permanent observed in 30% of cases.
Actually any abnormalities of the heart, accompanied by marked dilatation of the left atrium may be considered disease background, provoking the development of signs of atrial fibrillation.For this reason, aortic valvular heart disease are extremely rare disease background for atrial fibrillation.
separate category of patients are persons with congenital atrial septal defect and Ebstein's anomaly.Based on this fact, these patients require dynamic monitoring and echocardiographic monitoring throughout life.
During the surgery on the structures of the heart and coronary arteries should be considered that the data manipulation often provoke paroxysms of atrial fibrillation.The appearance of a violation of rhythm in this situation occurs in the postoperative period, and directly during the operations manual.The pathogenesis of atrial fibrillation put increased activity of sympathetic-adrenal system, acute myocardial hypoxia and damage to the pericardium.
By noncardiac causes of atrial fibrillation include alcoholism and thyroid disease with hyperthyroid syndrome.In the first situation, the occurrence of atrial fibrillation triggered by acute alcoholic intoxication or cardiomyopathy, since ethyl alcohol has an inhibitory effect on the conductivity of the atria.In hyperthyroidism, atrial fibrillation occurs as a result of potentiation effects of catecholamines in the process of atrial excitability.Overt hyperthyroidism, as a provocateur of atrial fibrillation observed in the elderly, and only 25% is accompanied by severe arrhythmic manifestations.
electrophysiological mechanism of atrial fibrillation is the formation of several waves rientri the atria, is fragile character, with the result that they are able to share in the subsidiaries of the wave.Thus, a combination of increasing the size of the atrial short wavelength rientri is the main condition for the development of atrial fibrillation.
Due to the fact that atrial fibrillation in most cases is accompanied by changes in hypercoagulable blood plasma and platelet activation of cells, this disease is the formation of intracardiac thrombi provocateur, which can then provoke thromboembolic complications.
Symptoms of atrial fibrillation
preliminary diagnosis "atrial fibrillation" experienced cardiologist can set during the initial contact with the patient, based on the history and physical examination of the patient.But it should be borne in mind that in some cases, atrial fibrillation is not accompanied by clinical symptoms and the discovery of her accounts at the time of the electrocardiograph inspection rights.However, the severity of the clinical manifestations of atrial fibrillation does not depend on the degree of increased frequency of heart rate and ventricular dysfunction reduction caused by the underlying disease.
onset of the disease is the appearance of the patient feeling heart palpitations, shortness of breath, dizziness, weakness, and their appearance is possible with any other pathologies, are not associated with impaired heart rhythm.The category of rare manifestation of atrial fibrillation is a short-term disturbance of consciousness and seizures typical anginal pain.
a result of increased natriuretic hormone synthesizing and improve the tone of the sympathetic-adrenal system, most patients report the appearance of such a pathognomonic symptom is polyuria.
Most of the patients with atrial fibrillation mark a sharp sudden debut of clinical manifestations against the backdrop of well-being, and only in rare cases, these changes are associated with excessive consumption of alcohol, coffee, stress and excessive influence of physical activity.
objective clinical examination of the patient followed by the detection of irregular heartbeat and a significant fluctuation of blood pressure numbers.The pulse in atrial fibrillation in most cases speeded up, and only when the existing weakness of the sinoatrial node is marked bradycardia.Auscultatory sign of atrial fibrillation is the appearance of the first tone clapping unequal sonority.
based division of atrial fibrillation in the clinical forms of the principle of its duration and the time of disappearance of not only clinical, but electrocardiographic signs.Cardiologists in the world using a single classification, according to which secrete several forms of atrial fibrillation.This separation is important for determining patient management and the selection of appropriate therapy.
most favorable for the life of the patient's atrial fibrillation is considered "nocturnal" in which the available clinical manifestations of self-leveled no later than 7 days.This option fibrillation is characterized by variability of clinical symptoms that may appear self-docked several times during the day.
In situations where clinical and electrocardiographic indicators of atrial fibrillation persist more than 7 days, cardiologists establish the diagnosis of "persistent" atrial fibrillation, and resort to medical methods for correcting cardiac arrhythmia.
most severe form of fibrillation is a "constant", whose symptoms persist even with the use of medication.In addition, atrial fibrillation can be divided into 3 types, depending on the accompanying increased frequency or heart rate deceleration.
Paroxysmal atrial fibrillation
Paroxysmal atrial fibrillation refers to the category of the most common types of cardiac arrhythmias, and the appearance of it depends on the disruption of the normal functioning of the sinus node, followed by a chaotic contraction of cardiomyocytes in the speeded up mode.These changes affect the entire structure of the circulatory system and lead to cardiohemodynamic disorders of varying severity.The most favorable option of paroxysmal atrial fibrillation is normosistolichesky in which there was no significant change in heart rate.
In a situation where a paroxysm of atrial fibrillation is characterized by a few episodes, we are talking about such a concept as "recurrence."At a young age often are unable to identify with certainty the time of the attack of atrial fibrillation with any causative factor, so in this situation, set the conclusion of "idiopathic paroxysmal atrial fibrillation."In the elderly, in most cases it is possible to recognize the occurrence of provocation paroxysm (ischemic myocardial injury, increased intracavitary pressure in the left atrium, the pathology of valvular heart disease, various forms of cardiomyopathy).
Most experts in the field of cardiology argue that the severity of clinical manifestations in the paroxysm of atrial fibrillation has a clear dependence on changes in heart rate, and in a situation where the rate does not change, the patient did not feel the changes in the state of his health.If a patient with a paroxysm of atrial fibrillation has been a significant acceleration of the heart rate, develops the classic clinical syndrome consisting of the sudden appearance of the feeling heart palpitations, feelings of failure of the heart, breathing difficulties and increasing shortness of breath, which is pathognomonic amplified in the supine position, expressed sweatingand an internal alarm.
reverse situation, when the paroxysms of atrial fibrillation occurs in the background of a significant decrease in the frequency of heart contractions, the patient manifested all the signs of hypoxia (loss of consciousness, lack of pulse and respiration activity).This state of the patient is critical and needs immediate conduct the full range of resuscitation.With this embodiment, the flow of paroxysmal atrial fibrillation significantly increases the risk of life-threatening conditions of the patient (cardiogenic shock, acute respiratory failure, cardiac arrest).For long-term effects, even short paroxysm of atrial fibrillation include activation of the processes of thrombus formation, which later become sources of embolic complications.
Determining the optimal treatment strategy of a patient with paroxysmal atrial fibrillation depends primarily on the time of attack.Thus, if the duration of an attack at the time of establishing the boundary does not exceed 48 hours, the primary goal of treatment is the complete restoration of sinus rhythm.In a situation where the duration of an attack of atrial fibrillation exceeds two days, the patient is recommended to conduct transesophageal echocardiography, which can detect even minimal thrombotic layers and establish the possibility of immediate restoration of sinus rhythm.
as first emergency room at first arisen paroxysm of atrial fibrillation is recommended Kordaron 5 mg / 1 kg body weight diluted in a 5% glucose solution to a 250 ml intravenous-drip, as the drug has a positive effect on the normalization of cardiacreductions in the shortest possible time with minimum side reactions.Prehospital most appropriate drug for relief of an attack of paroxysmal atrial fibrillation is Propanorm a daily dose of 600 mg orally.
diagnosis of atrial fibrillation
main diagnostic activities, enabling almost 100% of cases to establish a reliable diagnosis "atrial fibrillation" are echocardioscopy and electrocardiography.However, to determine the tactics and appropriate treatment regimen of patients with this form of arrhythmia is necessary to discover the cause of its origin, for which the patient is recommended to complete a full screening monitoring (coronary angiography, stress medication, tests, laboratory diagnostics of the thyroid gland and others).
Atrial fibrillation on ECG - the film has a characteristic pathognomonic features, allowing the right to establish not only the fact of the presence of atrial fibrillation, but also to determine its clinical form.The main ECG - the criteria for atrial fibrillation include: the emergence of chaotic waves atrial rate of 600 per minute varying amplitude and duration in the absence of P wave in all leads, check the various intervals RR, indicating a violation of rhythm of ventricular contraction, electrical alternation, is the appearance ofthe oscillation amplitude of the QRS complex and the complete absence of changes in its shape.
During the ECG - the study may detect indirect signs of focal myocardial ischemic disorders of nature, which allows to establish the cause of atrial fibrillation.
qualitative carrying echocardiography should contain data on myocardial contractility of the left ventricle, the state of valvular heart disease, the presence of intraluminal thrombotic deposits.
treatment of atrial fibrillation
Currently, the World Association of Cardiologists has been developed and used a single algorithm of therapeutic measures aimed at relief of atrial fibrillation.All methods of treatment of atrial fibrillation are applied either to reduce clinical symptoms, or as to prevent possible complications that threaten the patient's life.
Not all situations it is advisable to ensure the full restoration of normal sinus rhythm, and need only ensure optimal heart rate indicator.Sinus rhythm, you can achieve the complete elimination of symptoms of arrhythmia and hemodynamic disturbances caused by it, as well as significantly improve the patient's life.
When optimizing heart rate with the safety features of atrial fibrillation significantly grows the risk of thromboembolic disorders, so this category of patients in need of long-term use of anticoagulant therapy course.The best indicator of heart rate in the category of patients with permanent atrial fibrillation is considered to be one for 90 beats per minute, and the average annual daily heart rate recorded during the Holter monitoring, shall not exceed the mark of 80 beats per 1 minute.
In a situation where the patient is completely no clinical signs of hemodynamic instability and atrial fibrillation, should be resorted to delaying tactics within 72 hours, as almost 50% of the patients observed spontaneous leveling of a violation of cardiac rhythm.If the patient has symptoms of atrial fibrillation preservation, restoration of sinus rhythm promotes permanent appointment of antiarrhythmic therapy and electrical cardioversion.In addition, patients who have had persistent atrial fibrillation, reducing the need of optimal heart rate before the application of antiarrhythmic therapy (Digoxin 0.25 mg intravenously every 2 hours to achieve the highest possible dose of 1.5 mg orally in a daily Amiodarone800 mg, propranolol intravenously calculated dose of 0.15 mg / 1 kg body weight of the patient, verapamil intravenously at 0.15 mg / 1 kg body weight of the patient).