Acute atrial fibrillation is a type of arrhythmia, or abnormally fast or irregular heartbeat, that comes about suddenly but can persist for several hours or days. The problem results from changes in electrical activity in the heart that cause the atria, or upper chambers, to contract very quickly. The bottom chambers, the ventricles, cannot compensate for the fast contractions and deliver less blood to the lungs and the rest of the body. Acute atrial fibrillation can lead to extreme shortness of breath, mental confusion, and loss of consciousness. It is essential to seek emergency treatment when symptoms arise to avoid life-threatening heart failure or stroke.
Many different factors can contribute to acute atrial fibrillation. Blood clots, blood pressure medications, and complications following a heart attack are leading causes. A person may also develop symptoms after an episode of binge drinking or being electrocuted. Chronic health conditions such as high cholesterol, hyperthyroidism, and sick sinus syndrome may also cause a sudden attack of atrial fibrillation, but such conditions usually result in progressively worsening arrhythmia that develops over weeks or months.
The symptoms of acute atrial fibrillation tend to arise suddenly. A person may experience an immediate sensation of chest pain and tightness, shortness of breath, and lightheadedness. His or her pulse races and heartbeats can be felt by touching the chest. Lack of oxygen to the brain can cause extreme dizziness and mental confusion and possibly lead to fainting. Occasionally, an attack can end in a matter of seconds or minutes if electrical activity stabilizes, though symptoms tend to linger until medical attention is received.
A patient who exhibits life-threatening symptoms is usually given oxygen therapy and a blood-thinning medication to clear up any existing clots. An external defibrillator may be used to send a high-intensity electrical shock directly to the atria to get them back into a normal rhythm. Once the patient is stabilized, a series of imaging tests and electrocardiograms are taken to look for the underlying cause of the attack.
People who are able to recover following acute atrial fibrillation typically need to take daily medications called anti-arrhythmics to prevent recurring problems. Additional drugs can be prescribed if problems were caused by high blood pressure, cholesterol, or thyroid conditions. An individual who has repeat episodes may be fitted with an internal defibrillator that monitors heart rhythm and delivers a mild shock when it detects an abnormality. Patients are also given very specific instructions about dieting and exercise to reduce the chances of future complications.