Irregular heartbeat or Arrhythmias are abnormalities in the electrical activity of the heart. Atrial fibrillation (AF) is the most common cardiac arrhythmia. Your heart is made of four chambers; the right atrium and ventricle and the left atrium and ventricle. The blood from the body (on the right side) or the lungs (on the left side) enters the atrium and goes to the body via the ventricles. Atrium and Ventricles beat in sync with each other. Atrial fibrillation is a condition where the atria contracts independently of ventricles and at nearly 300 times per minute! AF results in a chaotic electrical activity in the atria of your heart.
Causes of Atrial Fibrillation
Development of AF is related to a number of risk factors like:
- Cardiovascular diseases like rheumatic heart disease, coronary artery disease
- Age: the prevalence increases with age
- Gender: males are more likely to develop AF
- Previous heart surgery
- Hyperactive thyroid gland
- Exposure to stimulants like alcohol or caffeine
Complications of Atrial Fibrillation
- The most common complication of AF is the formation of a blood clot i.e. a thrombus in the atria. The thrombus or a part of it may get dislodged and enter the circulation where it may block an artery in an organ like the brain leading to a stroke.
- Another complication of AF is heart failure. Uncontrolled AF leads to the weakening of the heart because of which your heart is unable to meet the demands of the body leading to heart failure.
Diagnosis of Atrial Fibrillation
To diagnose AF your doctor would like to take a detailed history and thoroughly examine your cardiovascular system. To confirm the diagnosis your doctor might order a few tests.
- Electrocardiogram (ECG): small leads will be placed on your chest to measure the electrical activity of your heart. The resulting electrocardiogram will help you doctor look for AF.
- Holter monitor: a version of ECG where you can freely move around. Holter monitor monitors the electrical activity of your heart for a prolonged interval as you go about your normal activities of the day; this will allow your doctor to catch AF and review your heart’s activity over a longer time interval.
- Echocardiogram: for this procedure, a probe will be placed on your chest. This probe produces sound waves which are used to visuals the chambers of your heart and the contents. They help in looking for clots in the atria; which are major side effects of prolonged AF. Another form of echocardiogram is a transesophageal echocardiogram where an ultrasound producing probe is passed into your food pipe via your mouth. This allows for better visualization of the chambers of the heart.
- Stress test: for this test, your heart will be monitored as you exercise.
- Chest X-Ray: the x-ray is done to look at the heart and the lungs
- Blood test: to check for levels of thyroid hormone and rule out the presence of substances that may cause and AF.
Symptoms of Atrial Fibrillation
Most of the individuals with AF are asymptomatic. Among those that are symptomatic the symptoms are:
Treatment of Atrial Fibrillation
The treatment regimen for AF depends on a number of factors like your blood pressure, the health of your heart and the rate of AF. The aim of the treatment is to
- Prevent stroke
- Control rate
- Control rhythm
Prevention of Stroke
Blood thinners or anticoagulants will be prescribed to reduce the risk of formation of blood clots. The choice of anticoagulant depends on multiple risk factors like age, accompanying heart failure, gender, coronary artery disease, blood pressure and accompanying diabetes mellitus. Drugs used are
- Beta-blockers: drugs like carvedilol, esmolol are used to control heart rate. They have the least side effect compared to other drugs used for rate control
- Calcium channel blockers: verapamil, diltiazem are administered to patients when beta-blockers are contraindicated. They are to be avoided in individuals with heart failure.
- Rhythm control: For individuals with AF there is a need for resetting of rhythm when an AF occurs, followed by maintaining the normal rhythm.
Resetting The Rhythm
There are two major methods to reset the rhythm.
- Electric cardioversion: after sedating you, an electric shock will be applied to your chest which will help in restoring the heart to its normal rhythm. Before this procedure, you will be given a blood thinner. If the AF has lasted for more than 48 hours then you will be required to take the blood thinner for the next 4 weeks
- Cardioversion with antiarrhythmics: when electric cardioversion is contraindicated due to the presence of a clot in the atria you will be given antiarrhythmics either orally or intravenously to control the rhythm of your heart. This will be done under the supervision of your doctor. After the rhythm normalizes your doctor might prescribe the same anti-arrhythmic for long-term control of heart rate.
Maintaining The Rhythm
Antiarrhythmic drugs act on the heart to maintain a regular rhythm. A common side effect of all these drugs is nausea, dizziness, and increased fatigue these drugs are:
There are surgical techniques to cure AF. When medications are unable to control the symptoms of AF your doctor might suggest you go for surgical intervention. In these procedures, the surgeon destroys the part of the atrium which is producing the erratic electrical signals.
Catheter ablation: a small tube called a catheter is inserted into a vein in your groin. The catheter moves forward and reaches the left atrium by piercing the septa between the two atria. The tip of the catheter destroys the tissue with the help of radiofrequency energy or extreme cold.
Surgical maze procedure: an open heart surgery is done to create precisely placed scars that cut the connections between the tissue producing an erratic electric signal and normal tissue hence normalizing the rhythm.
This blog has been published in collaboration with Prairie Cardiology, the premier Cardiology group in Illinois. Prairie Cardiovascular is a national leader in providing high-quality, state-of-the-art heart and vascular care. Make an appointment with one of the providers today, through ACCESS Prairie program.