Atrial Fibrillation: Diagnosis, Treatment and Prevention
Diagnosis, Treatment and Prevention
The heart is made up of two atriums and two ventricles. It is normal for blood to move sequentially from the atrium to the ventricle and from the ventricle to the lungs or the whole body by regular contraction and expansion of the atrium and ventricle. Atrial fibrillation is a type of arrhythmia (irregular pulse) disease in which the atrium does not beat regularly and various parts of the atrium beat disorderly, forming a very fast wave of 400 to 600 times per minute, resulting in an irregular pulse. Atrial flutter is a disease in which the atrium is beating as fast as about 300 times per minute, and there is regularity and arrhythmia is formed due to the structural characteristics of the inside of the heart.
Atrial fibrillation is a relatively common arrhythmia and symptom, which is found in about 0.4 to 0.9% of the general population, 2 to 4% of people over 60, 5% of people over 70, and about 12% of people over 80, and its incidence increases with age. It is also common in hypertension, valve disease, heart failure and coronary artery disease. It can also occur from stress, alcohol, chronic lung disease, hyperthyroidism, caffeine, infection and various metabolic disorders.
Atrial fibrillation can also be associated with WPW syndrome, a type of arrhythmia (Wolff-Parkinson-White syndrome, pre-excitation syndrome).
It is relatively commonly observed in the early post-cardiac surgery, up to 35-50%, usually due to sympathetic hyperactivity and inflammation after surgery. It can occur without special heart or lung disease. Paroxysmal atrial fibrillation can occur the next day after excessive drinking, which is sometimes referred to as holiday heart syndrome.
The mechanism of atrial fibrillation from an electrophysiological point of view is that a very large number of local electrical circuit abnormalities in the atrium occur, and procedures or surgical treatments that electrically separating or removing are commonly attempted in recent years. Atrial flutter also usually occurs when there is a pre-existing condition or factor that can cause atrial fibrillation.
As symptoms related to AF may range from none to disabling, and rhythm control treatment decisions are influenced by symptom severity, symptom status. The relation of symptoms (especially if non-specific, such as shortness of breath, fatigue, chest discomfort, etc.) to AF should be elucidated. Because symptoms may also result from undiagnosed or managed concomitant cardiovascular risk factors or pathological conditions.
To diagnose atrial fibrillation, your doctor may review your history and conditions of health. Your doctor may order several tests to diagnose as below.
Although it is not possible to diagnose arrhythmia through blood tests, basic blood tests are necessary as an initial test. In the case of first detected atrial fibrillation or flutter, hyperthyroidism may be the cause, and drugs such as amiodarone, which are commonly used in the treatment of atrial fibrillation, may cause not only liver dysfunction but also thyroid dysfunction, so be sure to test this.
In the case of atrial fibrillation, there is no characteristic normal P wave, but it appears only as a fine irregular line, and the interval between the QRS waves due to ventricular contraction is very irregular, and it can be easily diagnosed. In the case of atrial flutter, it can be diagnosed relatively easily by observing the characteristic serrated F-wave on an electrocardiogram, but sometimes, when 2:1 conduction is conducted to the ventricle, the pulse rate becomes regular 150 times, so it is necessary to distinguish it from other tachycardia have.
Holter inspection or event recording
In the case of paroxysmal atrial fibrillation, the electrocardiogram in the absence of atrial fibrillation is normal, so when atrial fibrillation occurs almost once every day or two, the easiest way to diagnose paroxysmal atrial fibrillation is when symptoms thought to be atrial fibrillation have occurred. When it comes to time, it is to record the electrocardiogram at a nearby hospital. In order to diagnose atrial fibrillation that is not useful or asymptomatic, a portable ECG machine in the size of a small recorder is worn for 24 to 48 hours, and a Holter test can be used for diagnosis. In rare cases, if atrial fibrillation is suspected, it is possible to perform event recording recorded on a portable electrocardiogram by pressing a button when symptoms develop while wearing it for about 2 weeks.
Exercise load test
Arrhythmia sometimes occurs when the heart is under stress. If symptoms of arrhythmia occur frequently during activity, an exercise stress test can be performed to diagnose arrhythmia.
Implantable event recorder
If atrial fibrillation is suspected, but it is difficult to secure an electrocardiogram when symptoms occur, an implantable event recorder is inserted into the body for accurate diagnosis. In addition, it can be usefully used for the detection of atrial fibrillation even when the choice of a drug varies depending on whether or not atrial fibrillation is accompanied, such as a stroke of unknown cause.
Since atrial fibrillation is well combined in hypertension, valve disease, and various cardiomyopathy, it is essential to evaluate the structural abnormality of the heart by echocardiography. In addition, atrial fibrillation can occur even if there is no structural abnormality of the heart. In the case of chronic atrial fibrillation, the size of the left atrium usually increases, and the larger the size, the less likely it is to return to a normal rhythm in the future. Therefore, measuring the size of the left atrium with echocardiography can also help predict the course of atrial fibrillation to some extent.
In addition, transesophageal echocardiography, which allows observation of the left atrium through the esophagus in close proximity to the left atrium in atrial fibrillation patients, may be performed before heart-related procedures or when trying to determine whether there is a blood clot (blood clot) in the left atrium in a stroke patient of unknown cause. . After the atrial fibrillation electrode catheterectomy treatment, an echocardiogram is needed to check for complications such as pericardial effusion (bleeding around the heart).
Additionally, often occurring in patients with cardiovascular risk factors/comorbidities, AF may sometimes be a marker of undiagnosed conditions. Hence, all AF patients will benefit from a comprehensive cardiovascular assessment as below.
For all AF patients
- AF-related symptoms
- AF pattern
- Concomitant conditions
Thyroid and kidney function, electrolytes and full blood count
For selected AF patients
Ambulatory ECG monitoring
- Adequacy of rate control
- Relate symptoms to AF recurrences
- Valvular heat disease
- LAA thrombus
cTnT-hs, CRP, BNP/NT-ProBNP Cognitive function assessment
Coronary CTA or ischaemia imaging
- Patients with suspected CAD
Brain CT and MRI:
Patients with suspected stroke
LGE-CMR of the LA:
To help decision-making in AF treatment
Asymptomatic clinical AF has been independently associated with increased risk of stroke and mortality compared with symptomatic AF. Screen-detected AF responds to treatment similarly to AF detected by routine care, thus favouring AF screening.
Although AF fulfils many of the criteria for disease screening, RCT data to confirm the health benefits from screening for AF and inform the choice of optimal screening programmes and strategies for its implementation are scarce.
The benefit of AF screening is as below.
Benefits of AF Screening
-Stroke/SE using OAC in patients at risk
-Subsequent onset of symptoms
-Electrical/mechanical atrial remodeling
-AF-related haemodynamic derangements
-Atrial and ventricular tachycardia-induced cardiopmyopathy
-AF-related morbidity; hospitalization; mortality
-The outcomes associated with conditions/ diseases associated with AF that are discovered and treated as a consequence of the examinations prompted by AF detection.
Currently, there are various types of screening machines as shown in the figure below, and they are increasingly evolving as wearable methods.
Advances in wearable technology will likely yield inexpensive and practical options for AF detection and AF burden assessment in the near future.
Treatment of atrial fibrillation is largely to restore/maintain a normal heartbeat, and treatment to prevent stroke, the most common complication in atrial fibrillation patients. Treatments to restore/maintain normal heartbeat include drug therapy, electrode catheterectomy or pulmonary vein isolation through cooling balloon resection, and surgical treatment.
1. Treatment to restore/maintain normal heartbeat
In the early stages of atrial fibrillation, it is possible to try to recover normal heartbeat with antiarrhythmic drug treatment, and it aims to relieve symptoms caused by tachycardia. However, it is difficult to expect a cure for atrial fibrillation through drug treatment.
Pulmonary vein isolation through electrode catheter resection or cooling balloon resection
Electrode catheter resection is a treatment developed to overcome the low efficiency and side effects of drug treatment. Unlike surgery, it is a procedure that fundamentally treats the cause of atrial fibrillation by inserting an electrode catheter tube into the femoral vein of the groin without a chest incision to approach the heart, and electrically isolating the pulmonary vein, which causes atrial fibrillation, from the left atrium with high-frequency energy. . In addition to the recent high-frequency electrode catheterectomy, cooling balloon resection has been introduced and is being actively performed. If it is performed early during the course of atrial fibrillation, it has a better effect of suppressing the reoccurrence of atrial fibrillation compared to drug treatment, and it is a procedure that can be performed relatively safely.
Another treatment for atrial fibrillation is surgery called a maize procedure. It is effective in restoring and maintaining normal heartbeat by blocking conduction of the regression circuit in the atrium that causes and maintains atrial fibrillation. However, after surgery, the function of the left atrium is not maintained as it is, and it is a relatively invasive treatment method that requires general anesthesia and chest incision, and is considered after drug and electrode catheter resection, or is given priority during open thoracic surgery such as heart valve disease. It is a cure. Recently, in addition to the maize procedure associated with conventional thoracotomy, arrhythmia surgery that can be performed minimally invasively with a thoracoscopic approach has been developed and is being actively performed.
To determine which method is best for treating a patient's atrial fibrillation, a plan should be made in consultation with the arrhythmia specialist.
2. Treatment to prevent stroke
In order to prevent the formation of blood clots due to atrial fibrillation and a stroke that may occur, oral anticoagulant treatment is combined. With the exception of atrial fibrillation patients with severe mitral stenosis or mechanical valves and atrial fibrillation patients undergoing dialysis, NOACs have been prescribed to prevent stroke in recent years. Patients with the aforementioned NOAC contraindications will take warfarin to prevent stroke.
You must maintain an appropriate weight through low alcohol consumption, proper diet, and exercise. If you have sleep apnea, you must treat it, conduct regular check-ups for diseases such as high blood pressure, diabetes, and heart disease, avoid severe stress, and get enough sleep.