The heart circulates blood throughout the body. The two upper chambers of the heart (atria) contract first, followed by the lower chambers, during each heartbeat (ventricles). These actions, when perfectly timed, resulting in a robust pump.
The electrical system of the heart controls the timing of cardiac contractions. The electrical impulse starts in the right atrium’s sinoatrial (SA node). The SA node, for example, increases the rate of impulses during exercise and decreases it during sleep. The electrical activity spreads over the right and left atria as the SA node fires an impulse prompting them to contract and force blood into the ventricles. The impulse goes via the septum to the atrioventricular (AV) node (near the middle of the heart). The only electrical bridge that allows impulses to flow from the atria to the ventricles is the AV node. The impulse causes the ventricles to contract as it travels through their walls.
Blood is pumped and squeezed out of the heart. The right ventricle pumps blood to the lungs, while the left ventricle pumps blood to the body. The rhythm is called “normal sinus rhythm” when the SA node directs the electrical activity of the heart. At rest, the normal heart beats in a steady rhythm of 60 to 100 times per minute.
What is atrial fibrillation?
The most irregular heart rhythm that occurs in the atria is atrial fibrillation. Instead of the SA node (sinus node) directing the electrical rhythm, numerous distinct impulses fire at once in the atria, resulting in a highly fast and chaotic beat. The atria cannot efficiently contract or squeeze blood into the ventricle because the electrical impulses are very rapid and disordered. Many impulses begin at the same time and spread through the atria, contending for a chance to move through the AV node rather than migrating in an orderly method through the heart. Although the AV node reduces the number of impulses that reach the ventricles, many impulses pass through an unorganized way. A rapid and irregular heartbeat is due to the ventricles that contract irregularly.
Some patients with atrial fibrillation can go years without experiencing any symptoms. Atrial fibrillation, on the other hand, can lead to future complications.
- Blood does not flow as quickly through the atria because they beat swiftly and unevenly. The blood is more likely to clot as a result of this. A clot pumped out of the heart can travel to the brain and cause a stroke. People with atrial fibrillation are 5 to 7 times more likely than the general population to have a stroke. Clots can also move to other regions of the body, causing harm to the kidneys, heart, and intestines.
- Atrial fibrillation impairs the heart’s ability to pump blood. Because of the irregularity, the heart may perform inefficiently. Furthermore, atrial fibrillation that persists for an extended period might damage the heart and lead to heart failure.
- A higher risk of stroke, heart failure, and possibly death is associated with atrial fibrillation.
Causes of Atrial Fibrillation
There is no specific cause of atrial fibrillation. It might be associated with different conditions. Cardiomyopathy, after heart surgery, heart valve disease, heart failure, coronary artery disease, high blood pressure, pulmonary hypertension, coronary lungs disease, and congenital heart disease are more common causes of this condition.
Pericarditis, viral infection, and hyperthyroidism are less common causes. In at least 10% of patients, there is no evidence of underlying cardiac disease. Atrial fibrillation may be associated with excessive caffeine or alcohol consumption, stress, certain medicines, electrolyte or metabolic abnormalities, severe infections, or genetic reasons in these circumstances.
None of such causes are present in some cases. The risk of atrial fibrillation rises with age, especially after 60.
Symptoms of Atrial Fibrillation
Atrial fibrillation can occur without causing any symptoms. If you’re experiencing symptoms, they could include lack of energy, dizziness, chest discomfort, shortness of breast, or heart palpitations. You may feel tired and lethargic. Older people mostly don’t have any symptoms.
Diagnosis
Atrial fibrillation is commonly diagnosed by the following tests:
- Holter monitor.
- Electrocardiogram (ECG or EKG).
- Portable event monitor.
- Transtelephonic monitor.
Holter monitor: A small external recorder is worn for one to three days. Electrodes (sticky patches) are attached to your chest skin. The electrodes are connected to the monitor by wires. The monitor continually records and stores the electrical impulses. After the monitor is removed, a technician analyses the data on a computer to determine the heart’s rhythm.
Electrocardiogram: The ECG shows the electrical impulses passing through the heart muscle on graph paper. An EKG is a recording of the heart’s electrical activity. A specific monitor may be needed to “catch” the arrhythmia in those who have intermittent symptoms.
Portable event monitor: A monitor is worn for almost a month for people who experience less frequent irregular episodes or symptoms. Electrodes (sticky patches) are applied to your chest. The electrodes are connected to the monitor by wires. When symptoms arise, the patient presses a button to activate the monitor. For several seconds, the instrument records the electrical activity of the heart. The patient then sends the device’s recorded data to the doctor’s office for evaluation over a phone connection. The portable event monitor might help you find which heart rhythm is causing your symptoms.
Transtelephonic monitor: A strip of your current heart rhythm can be transferred to your doctor’s office via the phone, using a monitor with two bracelets, or by pressing the monitor on your chest wall when you experience symptoms of atrial fibrillation.
Treatment
Regaining a normal heart rhythm (sinus rhythm), managing heart rate, preventing blood clots, and lowering the risk of stroke are all goals of treating atrial fibrillation. It is treatable by various methods including lifestyle changes, drugs, catheter-based procedures, and surgery. Your heart rhythm and symptoms will determine the type of treatment you receive. Medications are initially used to treat atrial fibrillation.
1- Antiarrhythmic drugs
Antiarrhythmic drugs aid in the restoration or maintenance of normal sinus rhythm in the heart. Procainamide, disopyramide, flecainide acetate, propafenone, sotalol, dofetilide, and amiodarone are examples of rhythm control drugs. When you start taking these medications you may need to stay in the hospital to have your heart rhythm closely monitored. These drugs are effective 30 to 60% of the time, but their effectiveness may deteriorate over time. To find the proper antiarrhythmic drug for you, your doctor may need to prescribe many different antiarrhythmic medications.
Some antiarrhythmic drugs may trigger arrhythmias, so it’s necessary to discuss your symptoms and any changes in your condition with your doctor.
2- Anticoagulant medications
Anticoagulant medicines like warfarin (Coumadin), warfarin substitutes, or aspirin can lower your risk of blood clotting and stroke but do not eliminate the risk.
When taking Coumadin, blood tests are performed regularly to assess its effectiveness. Regular blood tests are not required if you are using a warfarin substitute.
Consult your doctor to determine which anticoagulant medicine is best for you.
3- Rate control medications
To help lower the heart rate during atrial fibrillation, drugs like digoxin (Lanoxin), beta-blockers, and calcium channel blockers like verapamil (Calan) or diltiazem (Cardizem) are utilized.
These drugs do not regulate heart rate but keep the ventricles from pumping excessively fast.
4- Cardioversion therapy
A doctor may try to reset the heart rhythm (sinus rhythm) via a treatment called cardioversion if the atrial fibrillation symptoms are bothersome or if this is the first episode of atrial fibrillation. It can be done in two ways:
- Electrical cardioversion.
- Drug cardioversion.
In electrical cardioversion, electric shocks are sent to the heart through paddles or patches to reset the heart rhythm. To reset the heart rhythm, medications are given through an IV or mouth in drug cardioversion. Cardioversion is normally done as a scheduled operation in a hospital, although it can also be done in an emergency. To lower the risk of blood clots and strokes, warfarin or another blood thinner may be administered a few weeks before the procedure.
Anti-arrhythmic drugs may be taken indefinitely after electrical cardioversion to help prevent recurring episodes of atrial fibrillation. There’s a chance you’ll have another episode of atrial fibrillation, even if you’re on medicine.
5- Surgery
If atrial fibrillation does not improve with medicine or other treatments, a doctor may suggest a procedure called cardiac ablation. For some people, ablation is the first therapy option.
Cardiac ablation creates scars in your heart using heat (radiofrequency energy) or intense cold (cryoablation) to block faulty electrical signals and restore a regular heartbeat. A flexible tube (catheter) is inserted into your heart through a blood vessel, commonly in your groin. It’s possible to utilize more than one catheter. The cold or hot energy is applied through sensors on the catheter’s tip. Ablation with a scalpel is used less frequently during open-heart surgery.
Cardiac ablation comes in a variety of forms. The sort of atrial fibrillation treatment you receive is determined by your symptoms, overall health, and whether or not you are undergoing another heart surgery. Some of the types of cardiac ablation can be used to treat atrial fibrillation.
6- Maze Procedure
In the upper chambers of the heart, a doctor uses heat or cold energy or a knife to form a pattern of scar tissue (the maze). The maze interferes with stray heart signals that induce atrial fibrillation because scar tissue does not send electrical signals. If the maze design is made using a scalpel, open-heart surgery is required.
The surgical maze procedure is what it’s called. When another cardiac surgery, such as coronary artery bypass surgery or heart valve repair is required, it is the preferred technique of atrial fibrillation treatment.
7- Atrioventricular node ablation
To break the electrical signaling link, heat or cold energy is delivered to the heart tissue at the AV node. After AV node ablation, a pacemaker is required for the rest of one’s life.
After cardiac ablation, atrial fibrillation may reappear. If this occurs, another cardiac ablation or another type of heart treatment is required. To prevent strokes after cardiac ablation, lifelong blood thinners may be required.
If a patient with atrial fibrillation is unable to take blood thinners, a catheter treatment to seal a tiny sac (appendage) in the left upper heart chamber, where most A-fib-related clots develop, may be recommended. Left atrial appendage closure is the name for this operation. A catheter is used to gently guide a closure device to the sac.
The catheter is removed once the gadget is in position. The gadget is left in place indefinitely. For some persons who have already had cardiac surgery, surgery to seal the left atrial appendage is a possibility.
8- Changes in Lifestyle
There are certain adjustments you may make to improve your heart health.
- If some activities cause your abnormal heart rhythm to occur more frequently, avoid them and tell your doctor. Your prescriptions may need to be modified from time to time.
- Stop smoking.
- Consumption of alcohol should be limited. The key is moderation. Request a precise alcohol recommendation from your doctor.
- Caffeine should be used within limits. Caffeine sensitivity exists in some people, and they may experience more symptoms when using caffeinated items (such as tea, coffee, energy drinks, colas, and some over-the-counter medications).
- Be aware of cough and cold treatments that contain stimulants. These stimulants contain substances that may raise the risk of abnormal heart rhythms. Read the labels on your medications and consult your doctor or pharmacist to determine which sort of cold medicine is best for you.
- Keep your blood pressure in check.
- Get to a healthy weight if you’re obese or overweight.
- Maintain a healthy blood sugar level.
- Treat snoring and sleep apnea.
References:
- Zipes, Douglas et al. Developed in Collaboration With the European Heart Rhythm Association and the Heart Rhythm Society. ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines _, _J Am Coll Cardiol* 2006 48: e247-346.
- American Heart Association. “Premature Contractions.” Retrieved on March 1, 2011
- Heart Rhythm Society. “Heart Rhythm Disorders.” Retrieved on March 1, 2011
- The Merck Manuals Online Medical Library. “Ventricular Premature Beats (VPB).” Retrieved on March 1, 2011