Drugs for Atrial Fibrillation

What is Atrial Fibrillation?

Atrial fibrillation (also called AFib or AF) occurs when abnormal electrical impulses are suddenly generated in the upper chambers of the heart (atria). These impulses override the heart's natural pacemaker, which can no longer control rhythm of the heart. This leads to quivering or irregular heartbeat.

The normal range for a heart rate is 60 to 100 beats a minute; whereas, in atrial fibrillation, it may range from 100 to 175 beats a minute.

Atrial flutter is similar to atrial fibrillation, but the rhythm in atria is more organized and less chaotic than the abnormal patterns common with atrial fibrillation. At times, atrial flutter can develop into atrial fibrillation and vice versa.

What is New in Atrial-fibrillation?

What are the Symptoms of Atrial Fibrillation (AF)?

The most common symptom of an AF heart is quivering or fluttering heartbeat. Other symptoms one could experience are:

• Fluttering or thumping in the chest
• Confusion
• General fatigue or weakness
• Shortness of breath and anxiety
• Sweating
• Fatigue during exercise
• Pain or Pressure in the chest (this symptom is a sign of a medical emergency)

What are the Treatment options for Atrial Fibrillation (AF)?

Treatment options include:

1. Anti-arrhythmic drugs that control atrial fibrillation work

By restoring a normal heart rhythm - this approach is recommended for people who do not respond to rate control treatment. This treatment also may be used for people who have only recently started having AF.

Sodium channel blockers:

• Flecainide
• Disopyramide
• Mexiletine
• Procainamide
• Quinidine

Potassium channel blockers:

• Amiodarone
• Dronedarone - this drug must not be taken by patients who suffer from permanent AFib
• Sotalol - this drug is a beta blocker as well as a potassium channel blocker; hence, it controls both heart rate and heart rhythm
• Dofetilide

By controlling the rate at which heart beats - doctors can prescribe medicines to slow down the rate at which the ventricles are beating. These medicines help bring the heart rate to a normal level.

• Beta-blocker medicines (such as Atenolol, Timolol, Bisoprolol and Propranolol)
• Calcium-channel blocker medicines (such as Diltiazem and Verapamil)
• Digitalis glycosides (Digoxin) - This medicine may be suggested, in addition to above two, to help control the heart rate further. It decreases the electrical conductivity from atria to the ventricle. Effect of this drug reduces when the person is under lot of physical or emotional stress

2. Anti-coagulants or anti-platelets are prescribed to reduce risk of a stroke

People suffering from AF are at increased risk for stroke. Hence, preventing blood clots from forming is the most important part of treating AF. Doctors prescribe anti-coagulants or anti-platelets, also called blood thinners, to prevent formation of blood clots.

Anti-coagulant drugs include:

• Warfarin and Heparin
• New generation of anti-coagulants like Dabigatran, Rivaroxaban, Edoxaban and Apixaban

Anti-platelet medications include:

• Aspirin
• Clopidogrel
• Prasugrel
• Ticagrelor

3. Non-surgical procedures:

• Cardioversion - In this procedure, the heart is given a controlled electric shock to restore a normal rhythm.
• Catheter ablation - This approach may be used to restore a normal heart rhythm if medicines or electrical cardioversion do not work. For this procedure, a wire is inserted through a vein in the leg or arm, and threaded to the heart. Radio wave energy is sent through the wire to destroy abnormal tissue that may be disrupting the normal flow of electrical signals.

4. Surgical Procedures:

• Maze surgery - This is an open-heart surgery process to restore a normal heart rhythm. The surgeon makes small cuts or burns in the atria. These cuts or burns prevent the spread of disorganized electrical signals.
• Surgically fitting a pacemaker in heart - A pacemaker is a small, battery operated device which is implanted in the chest. It would help the heart to beat regularly, in rhythm.

What are the Side effects of AF medications?

Anti-arrhythmic drugs: The common side effects of different categories of anti-arrhythmic drugs are:

• Beta-blockers - tiredness, coldness of hands and feet, low blood pressure, nightmares and impotence
• Sodium channel blockers - nausea, vomiting and heart rhythm disorders
• Potassium channel blockers - sensitivity to sunlight (high-protection sunscreen must be applied to cover skin), lung problems, changes to liver function or thyroid function and deposits in the eye
• Calcium channel blockers - constipation, low blood pressure, swelling of ankle and heart failure
• Digoxin - changes in vision, mental health issues like anxiety, depression, hallucinations, headache and confusion

Anti-coagulant and anti-platelet medications: The main risk with these drugs is bleeding and the most serious side effect of these drugs is a bleed into the brain, known as "intracranial hemorrhage".

• Anti-coagulant Warfarin increases the risk of bleeding. A monthly blood test is necessary to monitor the side effect and to optimize the dose, if required.
• The newer anti-coagulants like Dabigatran do not require monthly blood test. However, precautions must be taken to prevent stroke. These medications are not approved for use in patients who have mechanical heart valves.
• Anti-platelet drugs like Aspirin too increase the risk of bleeding. Other side effects include bleeding gums, dark or bloody urine and nausea.

What Precautions must be noted when taking Atrial Fibrillation Medications?

• The doctor must evaluate the type of AF and suggest the type and dose of medicine. This is important as some medicines used to treat AF may cause another type of arrhythmia.
• These medicines can also harm people who have underlying diseases of the heart or other organs. This is especially true for patients who have an unusual heart rhythm problem called Wolff-Parkinson-White syndrome.
• If Warfarin or any other anti-coagulant is prescribed, regular blood tests (INR tests) must be conducted to keep a check on how quickly the blood clots.
• If there is any unusual bleeding or bruising, the healthcare provider must be consulted immediately, for remedial action.
• The patient must read the information leaflet which accompanies the medicine, for more details.

Health Tips to Avoid, Diagnose and Control Atrial Fibrillation

• Patients suffering from AFib are five times more likely to suffer from stroke. This risk is further increased if patients is suffering from diabetes and high blood pressure.
• Eat foods low in sugar and salt and watch the body weight, to control the blood sugar, blood pressure and risk of AFib complications.
• Patient must quit smoking. Studies show that current and former smokers have a higher risk of developing AFib. Smoking also increases the risk of stroke.

• If diagnosed with AFib, the doctor may prescribe blood thinners to lower the risk of stroke. These anti-coagulant drugs can interact with some foods, supplements, or even other medications. Be sure to ask your doctor what's safe to eat, and what foods to avoid, while taking your medications.

References:

1. Overview - Atrial Fibrillation - (http://www.mayoclinic.org/diseases-conditions/atrial-fibrillation/home/ovc-20164923)
2. How is Atrial Fibrillation treated? - (https://www.nhlbi.nih.gov/health/health-topics/topics/af/treatment)
3. Living with Atrial Fibrillation - (http://www.afibmatters.org/en_GB/Living-with-atrial-fibrillation)