What Is an Arrhythmia?

An arrhythmia is an uneven heartbeat. It means your heart is out of its usual rhythm.

It may feel like your heart skipped a beat, added a beat, or is "fluttering." It might feel like it’s beating too fast (which doctors call tachycardia) or too slow (called bradycardia). Or you might not notice anything.

Arrhythmias can be an emergency, or they could be harmless. If you feel something unusual happening with your heartbeat, get medical help right away so doctors can find out why it's happening and what you need to do about it.

Symptoms of Arrhythmias

An arrhythmia can be silent, meaning you don't notice any symptoms. Your doctor may spot an uneven heartbeat during a physical exam.

If you have symptoms, they may include:

• Palpitations (a feeling of skipped heartbeats, fluttering, or "flip-flops")
• Pounding in your chest
• Dizziness or feeling lightheaded
• Fainting
• Shortness of breath
• Chest pain or tightness
• Weakness or fatigue (feeling very tired)
• Anxiety
• Blurry vision
• Sweating

Arrhythmia Causes

You could have an arrhythmia even if your heart is healthy. Or it could happen because of:

• Heart disease
• The wrong balance of electrolytes (such as sodium or potassium) in your blood
• Heart injury or changes such as reduced blood flow or stiff heart tissue
• Healing process after heart surgery
• Certain medications
• Problems with the electrical signals in your heart
• Strong emotions, stress, or surprise
• Things in your daily life like alcohol, tobacco, caffeine, or exercise

Arrhythmia Risk Factors

Things that may make you more likely to have an arrhythmia include your:

• Age. The chances go up as you get older.
• Genes. Your odds might be higher if a close relative has had an arrhythmia. Some types of heart disease can also run in families.
• Lifestyle. Alcohol, tobacco, and recreational drugs can raise your risk.
• Medical conditions.High blood pressure, diabetes, low blood sugar, obesity, sleep apnea, and autoimmune disorders are among the conditions that may cause heart rhythm problems.
• Environment. Things in the world around you, like air pollution, can make an arrhythmia more likely.

Types of Arrhythmias

Arrhythmias are divided up by where they happen. If they start in the ventricles, or lower chambers of your heart, they’re called ventricular. When they begin in the atria, or upper chambers, they’re called supraventricular.

Doctors also group them by how they affect your resting heart rate. Bradycardia is a heart rate of fewer than 60 beats per minute. Tachycardia is more than 100 beats per minute.

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Supraventricular arrhythmias include:

• Premature atrial contractions. These are early extra beats. They’re harmless and generally don't need treatment.
• Atrial fibrillation (AFib). The upper chambers of your heart contract in an unusual way. Your heart might beat more than 400 times a minute.
• Atrial flutter. This is usually more organized and regular than atrial fibrillation. It happens most often in people who have heart disease and in the first week after heart surgery. It often changes to atrial fibrillation.
• Paroxysmal supraventricular tachycardia (PSVT). This is a rapid heart rate, usually with a regular rhythm. It begins and ends suddenly.
• Accessory pathway tachycardias. You can have a rapid heart rate because of an extra pathway between your heart's upper and lower chambers. Think of it as an extra road on your way home as well as your usual route. When that happens in your heart, it can cause a fast rhythm.
• AV nodal reentrant tachycardia (AVNRT). This is caused by an extra pathway through a part of your heart called the AV node. It can cause heart palpitations, fainting, or heart failure.

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Ventricular arrhythmias include:

• Premature ventricular contractions (PVCs). These are among the most common arrhythmias. They're the "skipped heartbeat" that many of us feel sometimes.
• Ventricular tachycardia (V-tach). This is a rapid heart rhythm starting from your heart's lower chambers. Because your heart is beating too fast, it can't fill with enough blood. This can be a serious arrhythmia, especially in people who have heart disease, and it may be linked to other symptoms.
• Ventricular fibrillation (V-fib). This happens when your heart's lower chambers quiver and can't contract or pump blood to the rest of your body. It’s a medical emergency that must be treated with CPR and defibrillation as soon as possible.
• Long QT syndrome. Your heart’s lower chambers take too long to contract and release. This may cause dangerous rhythm problems and death.

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Another type of arrhythmia, bradyarrhythmia, is a slow rhythm because of disease in your heart's electrical system or because of medication. It may make you pass out or feel like you will. Types of bradyarrhythmia include:

• Sinus node dysfunction. This is caused by a problem with your heart's sinus node, its natural pacemaker.
• Heart block. There’s a delay or a block of the electrical impulse as it travels from your heart's sinus node to its lower chambers.

Diagnosis of Arrhythmias

To diagnose an arrhythmia or find its cause, doctors use tests including:

• EKG. An electrocardiogram 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 (also called an "ambulatory electrocardiogram" or an ECG) about the size of a postcard or digital camera that you'll use for 1 to 2 days, or up to 2 weeks. The test measures the movement of electrical signals or waves through your heart. These signals tell your heart to contract (squeeze) and pump blood.  You'll have electrodes taped to your skin. It's painless, although some people have mild skin irritation from the tape used to attach the electrodes to the chest. You can do everything but shower or bathe while wearing the electrodes. After the test period, you'll go back to see your doctor. They'll download the information.
• Event monitor. If your symptoms don't happen often, your doctor may suggest that you wear one of these, usually for about a month. When you push a button, it records and stores your heart's electrical activity for a few minutes. Try to get a reading when you notice symptoms. Your doctor will interpret the results.
• Implantable loop recorder. Your doctor puts this under your skin, where it constantly records your heart’s electrical activity. It can send information to your doctor’s office.
• Stress test. There are different kinds of stress tests. The goal is to check how much stress your heart can manage before having a rhythm problem or not getting enough blood. For the most common type of stress test, you'll walk on a treadmill or pedal a stationary bike while you get an EKG and have your heart rate and blood pressure monitored. Technicians slowly raise the intensity level of your exercise.
• Echocardiogram. This test uses ultrasound to check your heart muscle and valves.
• Cardiac catheterization. Your doctor will insert a long, thin tube, called a catheter, into a blood vessel in your arm or leg. They’ll guide it to your heart with help from a special X-ray machine. Then, they’ll inject dye through the catheter to help make X-ray videos of your heart 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 trigger your unusual heart rhythm. Then, they may give you medications to see which one 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 and lying down. You'll get this test in a lab. You'll lie on a stretcher, tilted at different angles while you get an EKG and specialists check your blood pressure and oxygen level. This shows if symptoms of passing out are due to your electrical system, nervous system, or vascular system.

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