An arrhythmia is an irregular heartbeat the heart may beat too fast (tachycardia), too slowly (bradycardia), too early (premature contraction) or too irregularly (fibrillation).
Arrhythmias are heart-rhythm problems – they occur when the electrical impulses to the heart that coordinate heartbeats are not working properly, making the heart beat too fast/slow or inconsistently.
Many heart arrhythmias are harmless. We all occasionally experience irregular heartbeats, which may feel like a racing heart or fluttering. Some arrhythmias, however, especially if they veer too far from a normal heartbeat or result from a weak or damaged heart, may cause troublesome and even potentially fatal symptoms.
Rapid arrhythmias are called tachycardias, while slow ones are called bradycardias. Irregular arrhythmias – when the heartbeat is irregular – are called fibrillations, as in atrial or ventricular fibrillation. When a single heartbeat occurs earlier than it should it is called premature contraction.
The English word “arrhythmia” comes from the Greek word rhymos, meaning “rhythm”, the Greek suffix a (letter “a” added to the beginning of a word) means “loss” put together they mean “loss of rhythm”.
How do you lower your risk of an arrhythmia?
It is not always possible to prevent an arrhythmia developing, although a healthy lifestyle can lower your risk of developing a heart condition.
Treatment aims to prevent future episodes. You can also make lifestyle changes so you avoid some of the triggers for your heart rhythm problem.
Causes of arrhythmia
Normally, your heart works as a pump that brings blood to the lungs and the rest of the body.
To help this happen, your heart has an electrical system that makes sure it contracts (squeezes) in an orderly way.
- The electrical impulse that signals your heart to contract begins in the sinoatrial node (also called the sinus node or SA node). This is your heart’s natural pacemaker.
- The signal leaves the SA node and travels through the heart along a set electrical pathway.
- Different nerve messages signal your heart to beat slower or faster.
Arrhythmias are caused by problems with the heart’s electrical conduction system.
- Abnormal (extra) signals may occur.
- Electrical signals may be blocked or slowed.
- Electrical signals travel in new or different pathways through the heart.
Some common causes of abnormal heartbeats are:
- Abnormal levels of potassium or other substances in the body
- Heart attack, or a damaged heart muscle from a past heart attack
- Heart disease that is present at birth (congenital)
- Heart failure or an enlarged heart
- Overactive thyroid gland
Diagnosis of Arrhythmias
To diagnose an arrhythmia or find its cause, doctors use tests including:
- Electrocardiogram — Also called an EKG or ECG, this test records the electrical activity of your heart. You wear small electrode patches on your chest, arms, and legs for the quick, painless test, which you take in your doctor’s office.
- Holter monitor — This is a portable EKG that you’ll use for 1 to 2 days. You’ll have electrodes taped to your skin. It’s painless and you can do everything but shower while wearing the electrodes.
- Event monitor — If your symptoms don’t happen often, your doctor may suggest you wear one of these, usually for about a month. This is a device that, when you push a button, will record and store your heart’s electrical activity for a few minutes. Each time you notice symptoms, you should try to get a reading on the monitor. Your doctor will interpret the results.
- Stress test — There are different kinds of stress tests. The goal is to check how much stress your heart can manage before having a heart rhythm problem or not getting enough blood flow to the heart. For the most common type of stress test, you’ll walk on a treadmill or pedal a stationary bike at increasing levels of difficulty while you’re getting an EKG and getting your heart rate and blood pressure monitored.
- Echocardiogram — This test uses ultrasound to evaluate heart muscle and heart valves.
- Cardiac catheterization — Your doctor will insert a long, thin tube, called a catheter, into a blood vessel in your arm or leg. She will guide it to your heart with help from a special X-ray machine. Then she’ll inject dye through the catheter to help make X-ray videos of your heart’s valves, coronary arteries, and chambers.
- Electrophysiology study — This test records your heart’s electrical activities and pathways. It can help find out what’s causing heart rhythm problems and find the best treatment for you. During the test, your doctor will safely reproduce your abnormal heart rhythm and then may give you different medications to see which controls it best, or to see what procedure or device you need to treat it.
- Head-up tilt table test — Doctors use this test to find out what’s causing fainting spells. It measures the difference in heart rate and blood pressure when you’re standing up or lying down. You’ll get this test in a lab. You’ll lie on a stretcher, tilted at different angles while you’re getting an EKG and specialists are checking your blood pressure and oxygen level.
Your heart’s electrical system
The heart’s rhythm is controlled by electrical signals. An arrhythmia is an abnormality of the heart’s rhythm. It may beat too slowly, too quickly, or irregularly.
These abnormalities range from a minor inconvenience or discomfort to a potentially fatal problem.
Could you have an arrhythmia?
Symptoms of arrhythmias include palpitations, feeling dizzy, fainting and being short of breath, although having these symptoms does not always mean you have a heart rhythm problem.
Arrhythmia Alliance’s heart rhythm checklist can help you gather information to discuss with your GP if you have any of these symptoms.
Treatment for arrhythmia
When an arrhythmia is serious, you may need urgent treatment to restore a normal rhythm. This may include:
- Electrical “shock” therapy (defibrillation or cardioversion)
- Implanting a short-term heart pacemaker
- Medicines given through a vein (intravenous) or by mouth
Sometimes, better treatment for your angina or heart failure will lower your chance of having an arrhythmia.
Medicines called anti-arrhythmic drugs may be used:
- To prevent an arrhythmia from happening again
- To keep your heart rate from becoming too fast or too slow
Some of these medicines can have side effects. Take them as prescribed by your health care provider. Do not stop taking the medicine or change the dose without first talking to your health care provider.
Other treatments to prevent or treat abnormal heart rhythms include:
- Cardiac ablation, used to destroy areas in your heart that may be causing your heart rhythm problems
- An implantable cardiac defibrillator, placed in people who are at high risk of sudden cardiac death
- Pacemaker, a device that senses when your heart is beating irregularly, too slowly, or too fast. It sends a signal to your heart that makes your heart beat at the correct pace.