Cardiothoracic Surgery Patient Care - Pulmonary Hypertension
Atrial fibrillation (AF or afib) is an abnormal heart rhythm (cardiac arrhythmia) which involves the two small, upper heart chambers (the atria). Heart beats in a normal heart begin after electricity generated in the atria by the sinoatrial node spreads through the heart and causes contraction of the heart muscle and pumping of blood. In AF, the regular electrical impulses of the sinoatrial node are replaced by disorganized, rapid electrical impulses which result in irregular heart beats.
What is atrial fibrillation?
Atrial fibrillation (AF) is a type of cardiac arrhythmia. An arrhythmia is when the heartbeat becomes irregular or changes its rate inappropriately. An arrhythmia can occur for a number of reasons, but in cases of AF it happens when another part of the heart (often located at the pulmonary veins) tries to take over as the pacemaker. Many parts of the right and left upper chambers (atria) try to signal the heart to beat with rapid, irregular impulses. These impulses cause the upper heart to contract very rapidly, often so fast that the chambers "quiver" instead of "really" pumping. This fibrillation, or rapid contracting, of the atria interrupts the heart’s normal efficient pumping.
Atrial fibrillation is the most common cardiac arrhythmia. The risk of developing atrial fibrillation increases with age - AF affects four percent of individuals in their 80s. An individual may spontaneously alternate between AF and a normal rhythm (paroxysmal atrial fibrillation) or may continue with AF as the dominant cardiac rhythm without reversion to the normal rhythm (chronic atrial fibrillation). This variety of disorder is sometimes associated with the secretion of adrenalin under conditions of emotional stress in this age group.
Atrial fibrillation is often asymptomatic, but may result in symptoms of:
- chest pain
- heart failure
These symptoms are especially common when atrial fibrillation results in a heart rate which is either too fast or too slow. In addition, the erratic motion of the atria leads to blood stagnation (stasis) which increases the risk of blood clots that may travel from the heart to the brain and other areas.
Thus, AF is an important risk factor for stroke, the most feared complication of atrial fibrillation.
The symptoms of atrial fibrillation may be treated with medications which slow the heart rate. Several medications as well as electrical cardioversion may be used to convert AF to a normal heart rhythm. Surgical and catheter-based therapies may also be used to prevent atrial fibrillation in certain individuals. People with AF are often given blood thinners such as warfarin to protect them from strokes.