Arrhythmias

There are many types of arrhythmias, depending on what part of the heart is affected and whether they cause a slow, fast or irregular heart rate. Arrhythmias may happen in the atria (upper chambers of the heart) or the ventricles (lower chambers of the heart). Arrhythmias that cause a slow, fast or irregular heartbeat:

• Bradycardia is a resting heart rate that is slower than 60 beats per minute. Some people, especially people who are young or physically fit, may have slower heart rates. If you have a slow heart rate, your doctor can find out whether this is normal for you.
• Tachycardia is a resting heart rate that is faster than 100 beats per minute. You may also have an irregular heartbeat.
• A premature or extra heartbeat happens when the signal to beat comes too early. This creates a pause, which is followed by a stronger beat when your heart returns to its regular rhythm. It can feel like your heart skipped a beat. This is a common type of arrhythmia and can cause other types to happen. 

Most adults have a resting heart rate of between 60 and 100 beats per minute. Some smartwatches or smartphone apps can help you find out your resting heart rate.

Supraventricular Arrhythmias

This type of arrhythmia starts in the atria or the gateway to the lower chambers. 

• Atrial fibrillation is the most common type of arrhythmia. More than 2.5 million people in the United States have atrial fibrillation. This condition results from chaotic electrical signals in the upper chamber (atria) of your heart that make it beat irregularly. Typically, the heart rate is too fast as well as irregular though sometimes it can also beat too slowly. When this happens, your heart’s upper and lower chambers may not work together as they should and the heart may pump enough blood to your lungs and body.
• Atrial flutter also results from abnormal electrical signals in the atrium that overtake the heart’s rhythm. It can cause the upper chambers of your heart to beat as fast as 250 to 350 times per minute. Like atrial fibrillation, this can take over the heart’s rhythm causing the lower chambers to beat irregularly too. Atrial flutter is usually easier to treat than atrial fibrillation, but complications related to the two are similar.
• Paroxysmal supraventricular tachycardia (PSVT) causes rapid heartbeats because of abnormal electrical signals located between the upper and lower chambers of the heart. This type of arrhythmia usually begins and ends suddenly. It can happen spontaneously or during vigorous physical activity. It is usually easy to diagnose, not dangerous and often happens in young people.

Ventricular Arrhythmias

Ventricular arrhythmias start in your heart’s lower chambers, called the ventricles. These arrhythmias can be very dangerous and usually require medical care right away.

• Ventricular tachycardia is a fast, regular beating of your ventricles that may last for only a few seconds or for much longer. A few beats of ventricular tachycardia often do not cause problems. However, if this lasts for more than a few seconds, it can lead to more serious arrhythmias, such as ventricular fibrillation (VFib).
• Ventricular fibrillation occurs if electrical signals make the ventricles quiver instead of pumping normally. Without the ventricles pumping blood to the body, cardiac arrest and death can happen within a few minutes. 

An arrhythmia may not cause any obvious symptoms. You may notice symptoms such as a slow or irregular heartbeat or notice pauses between heartbeats. You may also feel like your heart is skipping a beat, fluttering, pounding, or beating too hard or too fast. These are called heart palpitations.

Other symptoms of arrhythmias include:

• Anxiety
• Chest pain or discomfort
• Confusion
• Difficulty breathing, or gasping during sleep
• Dizziness and fainting
• Tiredness or weakness

Keep track of when and how often you have symptoms, what you feel, what you were doing and whether these things change over time. If your symptoms are very serious, such as difficulty breathing or chest pain, seek emergency medical care. 

Sometimes, especially if you do not have any noticeable symptoms of an arrhythmia, your doctor may discover the condition during a routine screening or physical exam for a competitive sport. 

To diagnose an arrhythmia, your doctor will ask you about any symptoms, lifestyle habits and other risk factors of arrhythmias. Your doctor will also do a physical exam, which may include these steps:

• Checking for swelling in your legs or feet, which could be a sign of an enlarged heart or heart failure
• Checking your pulse to find out how fast your heart is beating
• Listening to the rate and rhythm of your heartbeat
• Listening to your heart for a heart murmur
• Looking for signs of other diseases, such as thyroid disease, that could be causing arrhythmias

If you or your child has a high risk of arrhythmias, your doctor may screen you regularly with heart tests. These tests, described in the next section, can help your doctor check whether your heartbeat is too fast, too slow or irregular, even if you do not have any symptoms. Some of these tests may look at the heart’s structure and function or may determine if you have risk factors for developing an arrhythmia.

Diagnostic tests

• An electrocardiogram (EKG or ECG) is the most common test for diagnosing arrhythmias. An EKG records your heart’s electrical activity. Your doctor may do an EKG during a stress test, which records your heart’s activity when it is working hard and beating fast. Your doctor may also do other tests to diagnose arrhythmias.
• Monitors for long-term recording include Holter monitors and implantable loop recorders. These record your heart rhythm while you do your normal activities. Holter monitors measure your heart rhythm using a device that is outside of your body and are usually used for several days to weeks. For an implantable loop recorder, your doctor will place the device under your skin. The recorder transmits data to your doctor’s office. Implantable loop recorders may be worn for several years and may help your doctor figure out why you are having palpitations or fainting spells, especially if these symptoms do not happen very often.
• An electrophysiology study (EPS), which is performed by an EPS cardiologist, measures the electrical activity of your heart. The doctor threads a wire through a blood vessel to your heart. The wire electrically stimulates your heart and triggers any underlying arrhythmia if you have one. If you have another condition that may raise your risk, an EPS can help your doctor find out your risk of developing arrhythmias. An EPS also allows your doctor to test whether a treatment, such as medicine, will stop the problem.
• If a serious arrhythmia is diagnosed, your physician may order additional tests of your heart. This is because many arrhythmias occur because of other heart diseases, such as coronary or valvular disease. Heart imaging tests, such as echocardiography, computed tomography (CT) scans or cardiac magnetic resonance imaging (MRI), may check the structure of your heart chambers, show how well your heart is working, look for evidence of scar tissue in your heart muscle and provide important clues about problems with your heart arteries. Cardiac catheterization may be needed to look directly for blocked arteries as the primary source of your arrhythmia.
• Routine blood tests are a simple way to look for causes of arrhythmias not directly related to the heart. Your physician can measure the level of certain substances in the blood, such as potassium or other electrolytes and thyroid hormones. Significant abnormalities can cause many kinds of arrhythmias, including dangerous ones. If found, the it is generally easy to correct the abnormalities and the arrhythmia.
• Genetic testing can check whether you have a type of arrhythmia that is caused by specific genes. These tests can be important and will be considered when one or more of your close relatives has an arrhythmia caused by a specific gene or had a cardiac arrest. 

Age, family history & genetics

• Age: As we age, changes in our heart such as scarring and the effects of other chronic conditions can raise the risk of arrhythmias. Older adults are also more likely to have health conditions, such as high blood pressure, heart attacks and heart failure, diabetes and thyroid disease, that can lead to arrhythmias. Arrhythmias caused by congenital heart defects or inherited conditions are more common in children and young adults.
• Family history: Arrhythmias can run in families. You may have an increased risk of some types of arrhythmias if a parent or other close relative has an arrhythmia. 

Lifestyle Habits 

Your risk of arrhythmias may be higher if you:

• Smoke
• Use illegal drugs, such as cocaine or amphetamines
• Drink alcohol more often and more than is recommended (no more than 2 drinks per day for men and 1 drink per day for women)

Medication & surgery

• Medication: Sometimes, medicines your doctor prescribes for other health conditions can cause an arrhythmia. Talk to your doctor about your risk of an arrhythmia if you are taking medicine to treat high blood pressure or for a mental health condition. Certain antibiotics and over-the-counter allergy and cold medicines can also raise the risk of arrhythmias in some people.
• Surgery: You may be at a higher risk of developing arrhythmias in the early days and weeks after surgery involving your heart, lungs or throat. 

Other Health Conditions

You may be more likely to have arrhythmias if you have:

• Heart and blood vessel diseases, such as cardiomyopathy, congenital heart defects, heart attack and heart inflammation
• Kidney disease
• Lung diseases, such as chronic obstructive pulmonary disease (COPD)
• Obesity
• Sleep apnea, which can stress your heart by preventing it from getting enough oxygen
• Too much or too little thyroid hormone
• Viral infections such as influenza (flu) or COVID-19

If you have any risk factors, certain situations may trigger an arrhythmia. These include any situations that make your heart work harder, raise your blood pressure or cause your body to release stress hormones. Triggers include:

• Blood sugar levels that are too low or too high
• Caffeine, illegal drugs and medicines that make you more alert or increase your energy
• Dehydration
• Low levels of electrolytes, such as potassium, magnesium or calcium
• Physical activity
• Strong emotional stress, anxiety, anger, pain or a sudden surprise
• Vomiting or coughing

Talk to your doctor about your triggers and what you can do to avoid them.

If you have a high risk of arrhythmias, your doctor may ask you to take some steps to help prevent them.

• Avoid triggers for arrhythmias.
• Get treatment for other health conditions that may cause arrhythmias.
• Make heart-healthy lifestyle changes, such as choosing heart-healthy foods, being physically active, aiming for a healthy weight, quitting smoking and managing stress.

Talk to your doctor if you need any heart procedures or surgery. Your healthcare team will manage your electrolyte levels and use medicine during or after the procedure to prevent an arrhythmia. 

If you have been diagnosed with an arrhythmia, make sure to follow your treatment plan. Keep your regular appointments with your doctor and ask about steps you can take to keep your arrhythmia from happening again or getting worse. Arrhythmias that are not diagnosed or are left untreated can cause complications affecting your heart and brain.