Normal Rhythm
Each of us has native pacemaker cells located in the right upper heart chamber (right atrium). These cells fire regularly at about 50 to 70 times per minute and activate the rest of the heart chambers causing the heart muscle to contract and eject blood into the arteries and veins. These pacemaker cells fire faster when we exercise or get excited and slow down when we rest and go to sleep.
Atrial Fibrillation (AF)
Atrial fibrillation (AF) results from multiple electrical impulses firing from both upper chambers of the heart (right and left atrium). It causes the heart to beat fast, very irregularly, and with less efficiency than with normal rhythm. AF can occur intermittently (paroxysmal AF). Episodes can occur frequently or rarely. They can last seconds, minutes, hours or days. AF can be persistent and require medical treatment to restore normal rhythm. It can also be permanent.
Causes
Many conditions are associated with development of atrial fibrillation. They include:
- Hypertension
- Coronary Artery Disease (CAD)
- Valvular heart disease
- Rheumatic heart disease
- Dilated cardiomyopathy
- Hypertrophic cardiomyopathy
- Pericarditis
- Coronary Artery Bypass Graft (CABG)
- Hyperthyroidism
- Pulmonary embolism
- Pneumonia
- Viral Illness
Sometimes it occurs in younger patients with structurally normal hearts and no obvious causes.
Symptoms
- Palpitations
- Dizziness
- Shortness of breath
- Chest pain
- Fatigue
Occasionally patients will have no symptoms and will be diagnosed during a routine doctor’s visit.
Evaluation
In addition to electrocardiographic documentation, a patient with AF will require evaluation of their heart to determine potential causes.
- Echocardiogram
- Stress tests
- Blood work
Complications
Because of the rapid, irregular and inefficient beating of the heart, AF can lead to:
- Dizziness and falls
- Congestive heart failure (CHF)
- Strokes
Strokes, which can be devastating, result from blood clots which form in the upper chamber of the heart. These clots can break off and travel to the brain.
Risk Factors & Prevention
This is accomplished with the use of blood thinner medications. The risk of stroke in any one patient is related to associated medical conditions including coronary artery disease, high blood pressure, age, diabetes, atherosclerosis and history of previous stroke.
There are two scales used for assessing risk: CHADS2 and CHADS2-VASC. The risk score of the patient will define which, if any, blood thinner medication should be prescribed. Blood thinners include:
- Aspirin
- Clopidogrel (Plavix)
- Warfarin (Coumadin)
- Rivaroxaban
- Apixaban
- Dabigatran