A heart arrhythmia is any type of irregular heartbeat. It could mean your heart is beating too fast, too slow or that the heartbeat is uncoordinated.
Atrial fibrillation, also called A-fib, is the most common cardiac arrhythmia. It is an irregular, rapid heart rate that can cause poor blood flow to the body. In patients with A-fib, the two upper chambers of the heart (the atria) are beating out of sync with the lower chambers.
A normal resting heart rate for an adult is between 60-100 beats per minute. A common heart rate for a patient with untreated atrial fibrillation is between 80-160 beats per minute. Since the atria quiver instead of contracting normally, the amount of blood pumped out of the heart with each beat is decreased.
Types of arrhythmias
There are many different types of rhythm disorders, some of the most common being:
- Atrial fibrillation: an irregular, and often rapid, heart beat that can cause a variety of symptoms and increase one’s risk for a blood clot leading to a stroke. Learn more about atrial fibrillation.
- Supraventricular tachycardia (SVT): a problem in the heart’s electrical system that causes episodes of a rapid heart rate, often triggered by exercise or caffeine.
- Ventricular tachycardia: a fast rhythm that starts in the lower part of the heart, the ventricles.
- Wolff-Parkinson-White Syndrome (WPW): a condition where the heart has an extra electrical pathway, leading to episodes of a very fast heartbeat.
- Bradycardia: a slower than normal heart rate that can lead to symptoms such as fatigue, dizziness or fainting.
- Premature beats: manifest as premature atrial or ventricular contractions (PACs or PVCs).
- Other less common types of congenital heart conditions that can led to arrhythmias include: Congenital Long QT Syndrome, Brugada Syndrome, Hypertrophic Cardiomyopathy and Arrhythmogenic Right Ventricular Dysplasia
Some patients do not experience any symptoms at all with atrial fibrillation. Patients who do experience symptoms may have:
- Palpitations (feeling that your heart is racing)
- Weakness, lightheadedness, dizziness or fainting
- Chest discomfort
- Change in exercise capacity
Causes of atrial fibrillation
Normally, the heart's electrical signal travels down a specific path to start the heartbeat. Patients with atrial fibrillation usually experienced previous damage or change to the heart’s structure. This can include:
- Coronary artery disease
- Hypertrophy (enlarged heart)
- High blood pressure (hypertension)
- Cardiomyopathy (weakening of the heart muscle)
- Congestive heart failure
- Pulmonary embolus
- Heart valve disease
- Excessive alcohol intake
- Excess weight
- Excess stress
- Excess caffeine
- Sleep apnea
- Overindulgence of strenuous exercise
Your physician will begin the diagnosis by asking you about your symptoms and your medical and family history. We will also perform a thorough physical exam. Learn more about cardiac imaging and diagnostic tests.
Other diagnostic tests may include:
- Electrocardiogram (EKG). This test is useful in diagnosing A-fib. If you experience an atrial fibrillation episode during the procedure, it will show up on the EKG. However, the EKG only shows what is happening with the heart at the time of the tracing.
- Electrophysiology (EP) Study: Using a catheter inserted into a blood vessel and moved up into the heart, an electrophysiologist studies your heart’s electrical system. He or she can purposely cause the abnormal heart rhythm in order to diagnose the problem.
- Holter or Event Monitors. Because patients spontaneously go in and out of atrial fibrillation, we may use a monitor to follow a tracing for a longer period of time. You can wear the monitor for up to 30 days at a time. The monitor will evaluate any rhythm disturbances.
- Implantable Loop Recorder. A small device placed underneath the skin that helps determine the cause of fainting. It can be used for up to several years.
In some cases, medication may help. In other cases, a minimally invasive procedure may be necessary. After initial assessment, your cardiac surgeon and cardiologist discuss your history, physical exam and diagnostic testing to determine the treatment plan. Learn more about arrhythmia treatment options.
Atrial fibrillation and stroke risk
During atrial fibrillation, blood tends to pool as the atria quiver or fibrillate instead of contract in an organized way. This makes it more likely that clots will form. Those clots can then dislodge and travel to the brain or other parts of the body. Atrial fibrillation patients are at higher risk for stroke compared to patients without A-fib or cardioembolic events.