Atrial fibrillation occurs when those electrical signals fire rapidly, causing the two upper chambers of the heart (the atria) to quiver.
Over time, an irregular heartbeat can:
- Weaken the heart and lead to heart failure
- Cause blood to pool in the heart, since the atria don't contract efficiently
- Lead to stroke as a result of blood clots forming in the pooled blood
Atrial fibrillation doesn't always have symptoms, but if they do appear, these are the most common:
- Chest pain
- Heart palpitations
- Shortness of breath
Atrial fibrillation can occur when someone has an underlying heart disease, such as heart valve disease, heart attack or heart failure.
Other conditions can also lead to atrial fibrillation, including sleep apnea, thyroid problems and certain lung diseases.
Some people with atrial fibrillation will experience a return to a normal heart rhythm without treatment.
Treatment depends on how bothersome your symptoms are and how long you've had them. For most people, treatment involves resetting the heart back to its normal rhythm with electrical pulses or controlling the heart rate.
Treatment can also involve a surgical procedure called catheter ablation, in which a catheter is guided through a blood vessel to the heart. Energy is then sent through the catheter to destroy the areas of tissue responsible for the arrhythmia.
In ventricular fibrillation, the lower chambers of the heart (the ventricles) quiver and can't pump any blood, which leads to collapse, then cardiac arrest.
Ventricular fibrillation is life-threatening and the most serious of all heart rhythm problems.
Cardiac arrest signs
If someone exhibits any of the signs of cardiac arrest below, call 911 immediately:
- A sudden lack of responsiveness
- Abnormal, gasping breaths
These are signs of sudden cardiac arrest and immediate medical help is necessary.
Ventricular fibrillation can be corrected with an automated external defibrillator (AED), which gives electrical shocks to the heart to restore its normal rhythm.
If you are alone with someone suffering from cardiac arrest, call 911 and get an AED if one is available. Use it as soon as you can.
While you wait for an ambulance, continue CPR until the person begins to respond or help arrives.