Atrial Fibrillation – causes, symptoms, investigations, treatment
Atrial fibrillation occurs most common among older people. In atrial fibrillation the heartbeats are irregular; the atrium downloads the electrical impulses with a high frequency. In this case the pump function of the heart will be affected.
During atrial fibrillation blood can accumulate in the atria, being possible to form blood clots. If such a clot will be mobilized into the systemic circulation, an embolic accident is unavoidable, such as ischemic stroke. For this reason, it is recommended that all patients with atrial fibrillation to follow anticoagulant or antiplatelet treatment which can prevent blood clots formation (for example: warfarin, acenocoumarol, and aspirin).
In this disease is affected the electrical activity of the heart. A wide range of diseases that affect the heart muscle or hemodynamic abnormalities underlie at the atrial fibrillation appearance.
Here is a list of the most common causes:
Arterial hypertension – The pressure of the arterial level is increased above 140 mm Hg systolic and 90 mm Hg diastolic pressures. This fact shall lead to hypertrophy of the heart muscle if does not interfere with hypotensive medication;
ischemic cardiomyopathy, myocardial infarction – the formation of atheroma plates on the arteries which irrigates the heart muscle (coronary arteries), will lead to a narrowing of the vessel lumen and consequently to decreasing in oxygen supply. If the atheroma plate cracks at that level, it will form a thrombus with complete obstruction of the artery and consequently will produce an acute myocardial infarction. Muscle irrigated by the obstructed artery will necrosis with subsequent development of fibrous tissue, proarrhythmic;
heart failure – in this condition the pump function of the heart decreases;
Diseases of the valves – mitral valve are most commonly affected. In mitral stenosis will increase the pressure in the left atrium which with time will expand and begin fibrils;
cardiomyopathy – in these disease it is affected the heart muscle (for example: excessive alcohol consumption, ischemic cardiomyopathy, severe valvular disease);
myocardial infection – data from viruses, fungi, bacteria (diphtheria), tuberculosis;
infections of the pericardium and the endocardium;
rheumatism – can affect the heart valves and muscle tissue;
Congenital disorders: atrial septal defect, etc.
Heart surgeries, such as valve prosthesis, myocardial revascularization by coronary artery bypass grafting, can cause atrial fibrillation. In any elderly people, heart surgery may underlie triggering the atrial fibrillation with increased risk of embolic stroke. Under treatment will be restored the normal rhythm of the heart in about two months.
Extra-cardiac conditions that cause atrial fibrillation
Chronic Obstructive Lung disease – chronic bronchitis, with chronic cough, 2 consecutive years, minimum 3 months per year;
pneumonia – lung infection caused by viruses or bacteria;
pulmonary embolism – the migration of some thrombi at the pulmonary artery level with the blocking of the blood flow towards the distal;
hyperthyroidism – thyroid hormone excess;
alcohol – excessive consumption causes atrial fibrillation, being proved to those who consume alcohol in large quantities, the occurrence of arrhythmias is more common than in those who do not consume alcohol or in very small quantities;
sympathomimetic medications: theophylline, amphetamines, ephedrine, drugs (cocaine, methamphetamine), caffeine, nicotine;
If the disease that caused the atrial fibrillation will be cured, usually it will be also restored the normal physiological heart rhythm.
In atrial fibrillation the following symptoms may occur:
palpitations – heart rate will be very irregular and with high frequent;
Dyspnea – is the sensation of breathlessness, air hunger. Very high pulse frequency of the heart will cause an increase in pressure in the pulmonary veins;
dizziness, faintness, confusion;
Angina pectoris – decreases the coronary arteries perfusion due to rapid heart rate and shortening of the diastole.
Most patients are asymptomatic, the diagnosis being usually made during some usual consultations, routinely. Some patients may complain of just feeling irregular heartbeats. Symptoms of atrial fibrillation may be minor but worsening progressive without treatment. It is important to detect the disease and treatment as early as possible. Before the diagnosis of atrial fibrillation can be diagnosed complications thereof, for example cerebral stroke, heart failure.
Here is a list of the most frequent factors that are incriminated in atrial fibrillation: age higher than 60, white race, male gender, damaged heart valves, heart failure, high blood pressure, heart attack, heart disease, surgery on the heart, acute rheumatic heart disease, lung disease, such as infection, hyperthyroidism, diabetes mellitus, excessive alcohol consumption, congenital diseases affecting the heart.
If you experience situations listed below we recommend you go to the doctor:
chest pain, chest high intensity;
Symptoms of a stroke;
feeling sick, fainting, loss of consciousness;
if you feel like irregular heartbeats;
Lack of air, hunger.
Atrial fibrillation recurrence
Recent studies have shown a link between atrial fibrillation and sleep apnea (breathing pauses in sleep, more than 10 seconds, repetitive episodes during a night). In these patients, after restoring the normal heart rhythm, the probability that the heart will enter again in atrial fibrillation, is higher than in patients who do not have sleep apnea. In patients with atrial fibrillation associated with obesity, it is advisable to perform a somnography to detect a possible sleep apnea. Treatment of sleep apnea will decrease the risk of recurrence of atrial fibrillation.
The detection of atrial fibrillation is done most commonly with the help of an electrocardiogram (records the electrical activity of the heart). It will be performed a case history, physical exam, the systematic measurement of blood pressure, a chest radiography. If atrial fibrillation is not documented when performing an electrocardiogram at rest, it can be made a 24-hour recording of the electrical activity of the heart using a Holter device. Ischemic heart disease may be highlighted by the achievement of a cardiovascular stress test. Echocardiography can detect the presence of any damage of the heart valves as well as quantification of the pump function of the heart. If it is established an anticoagulant treatment the patient with atrial fibrillation will be forced to perform a monthly analysis called INR, for the control of the anticoagulation efficiency.
Treatment – General things
It is important that the treatment of atrial fibrillation to be established quickly. A fast and irregular heart rhythm can lead to damaging the heart muscle and consecutive to heart failure, to angina pectoris. By the risk of clot formation in the left atrium (ears, left) will be established as soon as possible anticoagulant treatment. A treatment scheme well set; provide a normal life for most patients.
If atrial fibrillation has a very high heart rate or cause a significant increase in blood pressure it is recommended for patients to be hospitalized for further investigation and special treatment. Patients with asymptomatic or mild symptoms will be treated as outpatients. Initially, they will try to restore the normal rhythm of the heart, medicinal or by electrical conversion. It will be also necessary an initiation of anticoagulation treatment. In case arrhythmia started less than 48 hours, it will tempt conversion either electrical or medicinal to sinus rhythm (normal rhythm). If atrial fibrillation shows its duration of more than two days, it is not recommended to attempt conversion. In this case it is possible that the left atrial clots that have formed along with conversion might be mobilized into the systemic circulation (risk of stroke). Anticoagulants should be administered for 3 weeks and will be attempted later conversion to sinus rhythm. The conversion can be done after excluding the existence clot by performing a Transesophageal echocardiography (allows visualization of the left atrium and left ears the common location of clot forming).
If the onset moment of arrhythmia cannot be specified, it can be performed Transesophageal echocardiography checking this clot. If there are no clots, they will try restoring the normal, regular rhythm with the subsequent administration of anticoagulants. If they are detected clots anticoagulant, treatment will be established and subsequently will be tempt cardioversion.
Paroxysmal atrial fibrillation refers to arrhythmia that begins and suddenly disappears. Usually these episodes are becoming more frequent and starting with a longer duration. In this type of atrial fibrillation patient shows a higher risk of suffering a stroke thus will be prescribed oral anticoagulants (acenocoumarol). Concomitant presence of other heart diseases, arterial hypertension, diabetes and age over 75 years, cause an increased risk of embolic events. If the risk is low will be preferred aspirin administration.
Recurrent paroxysmal atrial fibrillation will be decreased by the administration of antiarrhythmic medications. It is not necessary continuous operational administration of antiarrhythmic medications, patients will be advised to administer this medicine only in the onset of arrhythmia.
Atrial fibrillation older than a few weeks is called persistent atrial fibrillation. In this case it is more difficult to convert. They will be given medication to control the heart rate and rhythm as well as anticoagulant treatment. An effective anticoagulation will be monitored by performing a prothrombin time.
Medicines to control heart rate
Rate control will be made in patients with persistent atrial fibrillation. Are used medications from: beta-blockers class, calcium blockers class, digoxin class. The purpose of this medication is to maintain a normal frequency below 100 beats per minute, avoiding very fast and dangerous frequencies.
Medicines to control heart rhythm
With the help of these medications they will try conversion to a normal rhythm, by sinus and maintaining it. Treatment will be individualized for each patient.
Orally administered anticoagulants
The purpose of this medication is to prevent clot formation due to the stagnation of blood in the fibrillating atria. The efficacy of these medications has been proven in numerous studies. Increased risks of stroke have patients who are hypertensive, diabetic, heart failure and suffered a transient ischemic stroke. If the risk of a patient is minimal or oral administration of the anticoagulant is contraindicated, should be described aspirin (platelet antiaggregant).
Treatment if the condition gets worse
There are patients who do not respond to medical treatment for the control of rhythm and frequency and will still have a rapid heartbeat and irregular. For these patients there is the option of radiofrequency ablation. Using a catheter to insert a probe to the heart and will seek the atrium area responsible for the unloading these abnormal electrical impulses that lead to fibrillation. A device probe tip will destroy these areas using heat. There are cases where the only solution is atrioventricular node ablation (by this node, impulses pass from the atria to the ventricles) with subsequent implantation of a pacemaker (pacemaker – device that will download regular electrical impulses, at least 60 per minute, causing contraction of the myocardium). This invasive maneuver (ablation) is very effective for paroxysmal atrial fibrillation (with the onset and sudden end), but less effective for persistent and permanent atrial fibrillation.
For patients who were operated on the heart and shows atrial fibrillation, becoming increasingly used procedure of scarring the heart muscle that eventually will break the excessive electrical impulses.
Evolution and risks
Atrial fibrillation in heart diseases
The most common causes are valvular atrial fibrillation, ischemic disease and hypertension. In general, patients in this case were older than 65. Treatment fibrillation will be quite difficult. It will be attempted cardioversion or by the medicinal method or by external electric shock. If this procedure is successful, they will use medications to control the heart rate and the patient remains in atrial fibrillation.
Isolated atrial fibrillation
There are cases where the cause of atrial fibrillation is not detected. Usually this situation occurs in individuals under the age of 65. In most cases, the arrhythmia will be handled with ease. Only 1 in 5 cases will progress to permanent atrial fibrillation. If the patient is symptomatic (general weakness, discomfort) treatment will be instituted. If the patient is younger than 75 years, will be required administration of oral anticoagulation. Atrial fibrillation may occur after cardiac surgery, but in general normal sinus rhythm of the heart will be restored after 2 months.
Atrial fibrillation and the risk of stroke
As I mentioned above, atrial fibrillation can lead to blood clots in the left atrium, especially at the ear level. If a clot at this level is mobilized into the systemic circulation, it can reach the brain causing ischemic stroke. The risk of a stroke in people with atrial fibrillation is more than 6 times compared to healthy individuals. The risk will increase if there is a concomitant valvular, if there is hypertension, diabetes or other vascular embolic events in the past.
Atrial fibrillation can be prevented by adapting a healthy lifestyle by treating a possible arterial hypertension, which is the prevention of cardiovascular disease. Smoking will be banned, avoiding stress, doing exercise and maintaining normal blood pressure. In the diet must be present meat, fish at least 2 times a week (salmon, tuna, and trout). Alcohol, caffeine, nicotine should be avoided.
In case of valvular infection will be performed infective endocarditis prophylaxis during the bleeding dental maneuvers.
Ways of living with atrial fibrillation
In patients undergoing anticoagulant treatment will be required certain precautions:
medication will be administered at a fixed time every day, if a day is omitted administration they will contact the specialist;
the medication will not be changed only after the consultation with the physician;
Attention to medicines containing aspirin, preferably should not be administered;
more recently, anticoagulant patients should wear a medical bracelet indicating this;
if the patient goes to the dentist, this one should be informed about his treatment;
the patient must recognize and submit to the doctor in case of bleeding;
monthly, the patient will perform analysis that indicates the efficiency of anticoagulation and need to adjust the treatment;
Foods like broccoli, cabbage, asparagus, and spinach contain vitamin K. For this reason they will decrease the effectiveness of treatment;
if the patient has digestive pathology and cannot feed a few days, call your doctor which has prescribed the anticoagulation treatment;
alcohol can be consumed, but in small quantities, because it decreases the effect of medications and also increases the risk of injuries and accidents leading to bleeding;
Smoking is not allowed;
should be avoided activities that predispose to trauma injuries, especially sports such as football, skiing;
Home should be properly designed to prevent falls.
When atrial fibrillation is given by a heart disease the treatment will be administered for long periods.
There will be administered preparations that lower cardiac frequency such as beta-blockers, calcium blockers, and digoxin. These medications are administered before antiarrhythmic medication. Antiarrhythmic medications are expensive, with more side effects. Frequency control will not lead to a normal, regular rhythm, but prevents the heart rhythm to reach dangerous, malignant rhythm. If the heart rate is between 60 and 100 beats per minute, the arrhythmia, irregular rhythm, will be very well tolerated.
More recently, have appeared anticoagulants that do not require monthly testing and frequent dosage adjustments as with warfarin.
There are surgical treatment variants by making some scar areas that will prevent the transmission of electrical signals from the atria to the ventricles (maze procedure). This option is taken into account only if medical treatment as well as radiofrequency ablation were not successful or if the patient is still undergo a surgery for other purposes (coronary artery bypass grafting, valvular prosthesis).