Atrial fibrillation (AF or A – fib) Brief description:
Atrial fibrillation is a type of cardiac arrhythmia that is characterized by irregular and abnormally fast heartbeats. The heart rate in AF is generally between 100 to 175 beats per minute. It starts as a brief period of arrhythmia but gradually becomes longer with time.
Types:
- Paroxysmal atrial fibrillation – Rapid, erratic heart rate that begins suddenly and lest for less than 24 hours but may last up to a week.
- Persistent atrial fibrillation – Abnormal heartbeats that resolve with medical intervention only and last for more than seven days.
- Long–term persistent atrial fibrillation – Continuous incidences of atrial fibrillation that last for greater than 12 months.
- Permanent atrial fibrillation – Abnormal heart rhythm is permanent, and medications are needed to keep heart rate in check.
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Causes of Atrial Fibrillation
AF occurs due to one or more of the following reasons:
- Abnormality in the heart’s anatomy or heart rate adjustment leading to variations in the electrical signaling.
- Premature or extra heartbeats.
- Presence of patches of faster or slower tissues in the heart.
- Repeated stimulation of certain tissue patches in the heart.
- Development of an atypical loop set off by a trigger heartbeat.
- Changes in heart tissue due to aging, infection, heart disease, or genetics.
- Fibrosis, inflammation, thickening, or thinning of the heart walls.
- Abnormal buildup of proteins, minerals, or cells in the heart tissue.
Risk factors:
- Age – Risk increases with age and is often higher in individuals above 65 years of age.
- Genetics – Family history of AF increases the risk by 40 %. Mutations in the genes of ion channels also increase the rate of AF.
- Alcohol – Binge drinking increases the risk at a higher rate than low – to – moderate alcohol consumption.
- Unhealthy lifestyle habits – Sedentary lifestyle, lack of physical activity, and drug abuse can trigger or aggravate AF.
- Stress – Panic disorders and other types of emotional stress are associated with the development of AF.
- Medical conditions – Obesity, high blood pressure, congenital heart defects, sleep apnea, and diabetes are some of the health conditions that raise the risk of AF.
- Ethnicity – People of European ancestry and Whites are more susceptible to developing AF than African Americans.
- Cardiac surgery – Previous heart surgery and surgery to correct congenital heart defects raise the risk of AF.
- Medications – Dobutamine, chemotherapeutic agents like cisplatin, NSAIDs, adenosine, and corticosteroids increase the risk of developing AF.
Signs and symptoms:
- Heart palpitations
- Exercise intolerance
- Fatigue
- Shortness of breath
- Lightheadedness
- Difficulty breathing
- Chest pain or discomfort
Complications:
Serious complications that arise due to untreated AF are:
- Venous thromboembolism
- Alzheimer’s disease
- Vascular dementia
- Heart attack
- Heart failure
- Stroke
- Sudden cardiac arrest
Diagnosing Atrial Fibrillation
- The physician assesses medical history – Diet, physical activity habits, family history, and other risk factors.
- Physical examination – Heart rhythm, blood pressure, pulse rate, and other physical abnormalities are checked by the physician.
- Diagnostic tests –
- Blood tests – Complete blood count, levels of potassium, and other electrolytes are determined.
- Thyroid-stimulating hormone (TSH) test – Low levels of serum TSH indicate an increased risk of AF.
- Echocardiography – This test identifies regions of poor blood flow in the heart, previous injury to the heart muscle, and harmful blood clots.
- Electrophysiology study (EPS) – The heart’s electrical system is evaluated and checked for abnormal heart rhythms.
- Holter and event monitors – Records the heart’s electrical activity while doing normal daily activities for long periods.
- Loop recorder – Devices implanted in the chest area to monitor the heart’s electrical activity for months.
- Sleep study – To ascertain if sleep apnea is responsible for AF.
- Exercise stress test – Helps to identify the changes in the heart’s activity during and after exercise.
- Transesophageal echocardiography – To detect blood clots in the atria, especially in the left atria.
- Walking test – Helps to measure the heart activity while walking for 6 minutes to determine how the heart behaves under normal circumstances.
- Electrocardiogram (ECG)
- Chest x-ray
Treatment of Atrial Fibrillation
AF is treated to manage the symptoms and reduce the risk factors that aggravate the condition. It also helps to prevent blood clots and reduce the risk of stroke.
- Surgery –
- AF catheter ablation – A catheter is used to destroy the tissue inside the heart responsible for the arrhythmia.
- Atrioventricular node ablation – The AV node is ablated to stop the irregular impulses from reaching the ventricles. The ablation is done after implanting a pacemaker.
- Cardioversion –
- Electrical cardioversion – A defibrillator is used to send a low-energy electric shock to the heart. It is done if medications are not effective.
- Pharmacological or chemical cardioversion – Anti–arrhythmic medications like amiodarone or sotalol are given intravenously or orally in the hospital to restore the normal heart rhythm.
- Medications – The medications that are commonly prescribed are:
- Beta-blockers – Metoprolol, carvedilol, etc., to lower the rate with which the ventricles pump blood throughout the body.
- Blood thinners – Edoxaban, dabigatran, etc.-prevent the formation of blood clots and reduce the risk of stroke.
- Calcium channel blockers – like Diltiazem, verapamil, etc. reduce the number of impulses that pass through the AV node to ventricles to lower the heart rate.
- Digitalis, or digoxin – It is used with caution to increase the pumping force and reduce the heart rate.
Prevention:
- Living with AF –
- Regular checkup and follow-up care.
- Eating a heart-healthy diet with low salt intake.
- Being physically active.
- Quitting smoking.
- Managing a healthy weight.
- Avoiding alcohol and substance abuse.
- Preventing AF –
- Managing blood pressure.
- Avoiding large quantities of caffeine.
- Treating other underlying conditions like diabetes, sleep apnea, etc.
When to see a doctor? :
It is best to consult with a cardiologist when the AF episode lasts for 24 to 48 hours without any break or if the symptoms aggravate over time. The cost of catheter ablation ranges from Rs. 70K to 1 lakhs.