A heart arrhythmia may not cause any symptoms. The irregular heartbeat may be noticed during a health checkup for another reason.

Symptoms of an arrhythmia may include:

• A fluttering, pounding or racing feeling in the chest.
• A fast heartbeat.
• A slow heartbeat.
• Chest pain.
• Shortness of breath.

Other symptoms may include:

• Anxiety.
• Feeling very tired.
• Lightheadedness or dizziness.
• Sweating.
• Fainting or almost fainting.

When to see a doctor

If you feel like your heart is beating too fast or too slow, or it's skipping a beat, make an appointment for a health checkup. You may be told to see a doctor trained in heart diseases, called a cardiologist.

Get emergency medical care if you have these heart symptoms:

• Chest pain.
• Shortness of breath.
• Fainting.

Always call 911 or your local emergency number if you think you might be having a heart attack.

A type of arrhythmia called ventricular fibrillation can cause a dramatic drop in blood pressure. This can cause the person to fall to the ground within seconds, also called collapse. Soon the person's breathing and pulse will stop. Ventricular fibrillation is an emergency that needs immediate medical help. It's the most frequent cause of sudden cardiac death.

If this happens, follow these steps:

• Call 911 or your local emergency number.
• If there's no one nearby trained in cardiopulmonary resuscitation (CPR), provide hands-only CPR. Push hard and fast on the center of the chest. Do 100 to 120 compressions a minute until medical help arrives. You do not need to breathe into the person's mouth.
• CPR helps keep blood flowing to the organs until an electrical shock can be given with an automated external defibrillator (AED). An AED is a device that delivers a shock to restart the heart.
• If an AED is available nearby, have someone get the device and follow the instructions. No training is required to use it. The device tells you what to do. It's programmed to allow a shock only when appropriate.

To understand the cause of heart arrhythmias, it may help to know how the heart works.

How does the heart beat?

The typical heart has four chambers.

• The two upper chambers are called the atria.
• The two lower chambers are called the ventricles.

The heart's electrical system controls the heartbeat. The heart's electrical signals start in a group of cells at the top of the heart called the sinus node. They pass through a pathway between the upper and lower heart chambers called the atrioventricular (AV) node. The movement of the signals causes the heart to squeeze and pump blood.

In a healthy heart, this heart signaling process usually goes smoothly, resulting in a resting heart rate of 60 to 100 beats a minute.

But some things can change how electrical signals travel through the heart and cause arrhythmias. They include:

• A heart attack or scarring from a previous heart attack.
• Blocked arteries in the heart, called coronary artery disease.
• Changes to the heart's structure, such as from cardiomyopathy.
• Diabetes.
• High blood pressure.
• Infection with COVID-19.
• Overactive or underactive thyroid gland.
• Sleep apnea.
• Some medicines, including those used to treat colds and allergies.
• Drinking too much alcohol or caffeine.
• Illegal drug use or drug misuse.
• Genetics.
• Smoking.
• Stress or anxiety.

Things that may increase the risk of heart arrhythmias include:

• Coronary artery disease, other heart problems and previous heart surgery. Narrowed heart arteries, a heart attack, heart valve disease, prior heart surgery, heart failure, cardiomyopathy and other heart damage are risk factors for almost any kind of arrhythmia.
• High blood pressure. This condition increases the risk of developing coronary artery disease. It also may cause the walls of the left lower heart chamber to become stiff and thick, which can change how electrical signals travel through the heart.
• Heart problems present at birth. Also called congenital heart defects, some of these problems may affect the heart rate and rhythm.
• Thyroid disease. Having an overactive or underactive thyroid gland can raise the risk of irregular heartbeats.
• Obstructive sleep apnea. This condition causes pauses in breathing during sleep. It can lead to a slow heartbeat and irregular heartbeats, including atrial fibrillation.
• Electrolyte imbalance. Substances in the blood called electrolytes help trigger and send electrical signals in the heart. Potassium, sodium, calcium and magnesium are examples of electrolytes. If the body's electrolytes are too low or too high, it may interfere with heart signaling and lead to irregular heartbeats.
• Some medicines and supplements. Some prescription medicines and certain cough and cold treatments can cause arrhythmias.
• Excessive alcohol use. Drinking too much alcohol can affect electrical signaling in the heart. This can increase the chance of developing atrial fibrillation.
• Caffeine, nicotine or illegal drug use. Stimulants can cause the heart to beat faster and may lead to the development of more-serious arrhythmias. Illegal drugs, such as amphetamines and cocaine, may greatly affect the heart. Some may cause sudden death due to ventricular fibrillation.

Complications depend on the type of heart arrhythmia. Possible complications of heart arrhythmias include:

• Blood clots, which can lead to stroke.
• Heart failure.
• Sudden cardiac death.

Blood-thinning medicines can lower the risk of stroke related to atrial fibrillation and other heart arrhythmias. If you have a heart arrhythmia, ask a healthcare professional if you need to take a blood thinner.

If an arrhythmia is causing heart failure symptoms, treatment to control the heart rate may help the heart work better.

Lifestyle changes used to manage heart disease may help prevent heart arrhythmias. Try these heart-healthy tips:

• Don't smoke.
• Eat a diet that's low in salt and saturated fat.
• Exercise at least 30 minutes a day on most days of the week.
• Maintain a healthy weight.
• Reduce and manage stress.
• Control high blood pressure, high cholesterol and diabetes.
• Get good sleep. Adults should aim for 7 to 9 hours daily.
• Limit or avoid caffeine and alcohol.

To diagnose a heart arrhythmia, a healthcare professional examines you and asks about your medical history and symptoms.

You may have tests to check your heart and to look for health conditions that can cause an irregular heartbeat.

Tests

Tests to diagnose a heart arrhythmia may include:

• Electrocardiogram (ECG or EKG). This quick test measures the electrical activity of the heart. It can show how fast or how slow the heart is beating. Sticky patches called sensors are attached to the chest and sometimes to the arms or legs. Wires connect the patches to a computer, which displays or prints results.
• Holter monitor. This portable ECG device can be worn for a day or more to record the heart's activity during daily activities.
• Event recorder. This portable ECG device is worn for up to 30 days or until an arrhythmia or symptoms occur. You typically press a button when symptoms occur.
• Echocardiogram. This test uses sound waves to take pictures of the beating heart. It can show the structure of the heart and heart valves. It can measure the strength of the heart. It also shows how blood flows through the heart.
• Implantable loop recorder. If symptoms are very infrequent, an event recorder may be implanted under the skin in the chest area. The device continuously records the heart's electrical activity. It can find irregular heart rhythms.

If an irregular heartbeat is not found during those tests, a healthcare professional may suggest more tests to try to trigger the arrhythmia. These tests may include:

• Stress test. Some arrhythmias are triggered or worsened by exercise. During a stress test, the heart's activity is watched while you ride on a stationary bicycle or walk on a treadmill. If you can't exercise, you may be given medicine that affects the heart in a way that's similar to exercise.
• Tilt table test. This test may be done if you've had fainting spells. Your heart rate and blood pressure are checked as you lie flat on a table. The table is then tilted to put you in a standing position. A healthcare professional watches how your heart and nervous system respond to the change in angle.

• Electrophysiological (EP) testing and mapping. This test, also called an EP study, can confirm a diagnosis of tachycardia or find out where in the heart the faulty signaling occurs. An EP study is mostly used to diagnose isolated arrythmias.

  An EP study is done in the hospital. One or more thin, flexible tubes are guided through a blood vessel, usually in the groin, to various areas in the heart. Sensors on the tips of the tubes record the heart's electrical activity. An EP study shows how electrical signals spread through the heart during each heartbeat.

Treatment for a heart arrhythmia depends on whether the heart is beating too fast or too slow. Some heart arrhythmias do not need treatment. Your healthcare team may suggest regular checkups to watch your condition.

Heart arrhythmia treatment is usually only needed if the irregular heartbeat causes significant symptoms or puts you at risk of more-serious heart problems. Treatment for heart arrhythmias may include medicines, special actions called vagal maneuvers, procedures or surgery.

Medicines

Medicines used to treat heart arrhythmias depend on the type of irregular heartbeat and possible complications.

For example, most people with tachycardia are given medicine to control the heart rate and rhythm.

If you have atrial fibrillation, blood thinners may be given to prevent blood clots.

Therapies

Other treatments for heart arrhythmias include:

• Vagal maneuvers. These are simple but specific actions that can slow the heart rate. They include coughing, bearing down as if having a bowel movement and putting an ice pack on the face. These actions affect the vagus nerve. The nerve helps control the heartbeat. Vagal maneuvers may be recommended if you have a very fast heartbeat due to supraventricular tachycardia. Vagal maneuvers don't work for all types of arrhythmias.
• Cardioversion. Paddles or patches on the chest are used to give an electrical shock to the heart and help reset the heart rhythm. Cardioversion is typically used when vagal maneuvers and medicines don't work. Your healthcare team may recommend this treatment if you have a certain type of arrhythmia, such as atrial fibrillation.

Surgery or other procedures

Treatment for heart arrhythmias also may involve a procedure or surgery to place a heart device in your body. Sometimes, open-heart surgery is needed to stop or prevent an irregular heartbeat.

Types of procedures and surgeries used to treat heart arrhythmias include:

• Catheter ablation. In this procedure, the doctor places one or more catheters into blood vessels to the heart. Sensors at the catheter tips use heat or cold energy to create tiny scars in your heart. The scars block irregular heart signals and restore the heartbeat.
• Pacemaker. If slow heartbeats don't have a cause that can be fixed, a pacemaker may be needed. A pacemaker is a small device that's placed in the chest to help control the heartbeat.

• Implantable cardioverter-defibrillator (ICD). This device is placed under the skin near the collarbone. It continuously checks the heart rhythm. If the device finds an irregular heartbeat, it sends out low- or high-energy shocks to reset the heart's rhythm.

  You may need this device if you have a high risk of dangerously fast or irregular heartbeats in the lower heart chambers. Such conditions are called ventricular tachycardia or ventricular fibrillation. Other reasons for an ICD include a history of sudden cardiac arrest or conditions that increase its risk.

• Maze procedure. In the maze procedure, a surgeon makes tiny cuts in the upper half of the heart to create a pattern of scar tissue. The pattern is called a maze. The heart's signals can't pass through scar tissue. This treatment can block stray electrical heart signals that cause some types of fast heartbeats.

  The maze procedure is usually only done if you don't get better with other treatments or if you're already having open-heart surgery for another reason.

• Coronary bypass graft surgery. If you have severe coronary artery disease with an irregular heartbeat, you may need this type of heart surgery. The surgery creates a new path for blood to flow around a blocked or partially blocked artery in the heart.

After treatment for irregular heartbeats, it's important to get regular health checkups. Take your medicines as directed. Tell your healthcare team if your symptoms get worse.

Making lifestyle changes can help keep your heart as healthy as possible.

Examples of heart-healthy lifestyle changes are:

• Eat heart-healthy foods. Eat a healthy diet that's low in salt and solid fats and rich in fruits, vegetables and whole grains.
• Get regular exercise. Try to exercise for at least 30 minutes on most days.
• Don't smoke. If you smoke and can't quit on your own, talk to a healthcare professional about strategies or programs to help.
• Maintain a healthy weight. Being overweight increases the risk of heart disease. Talk with your care team to set realistic goals for body mass index (BMI) and weight.
• Control blood pressure and cholesterol. High blood pressure and high cholesterol increase the risk of heart disease. Make lifestyle changes and take medicines as directed to manage high blood pressure or high cholesterol.
• Limit alcohol. If you choose to drink alcohol, do so in moderation. For healthy adults, that means up to one drink a day for women of all ages and men older than age 65, and up to two drinks a day for men age 65 and younger.
• Practice good sleep habits. Poor sleep may increase the risk of heart disease and other chronic conditions. Adults should aim to get 7 to 9 hours of sleep daily. Go to bed and wake at the same time every day, including on weekends. If you have trouble sleeping, talk to a healthcare professional about strategies that might help.
• Manage stress. Managing stress is an important step in keeping the heart healthy. Getting more exercise, practicing mindfulness and connecting with others in support groups are some ways to reduce and manage stress.

Medical appointments can be brief. There's often a lot to discuss. So it's a good idea to be prepared for your appointment. Here's some information to help you prepare for your appointment.

What you can do

• Be aware of any pre-appointment restrictions. When you make the appointment, ask if there's anything you need to do in advance. For example, you may be told not to eat or drink for a few hours before a cholesterol test.
• Write down any symptoms you're having, including any that may seem unrelated to heart arrhythmias.
• Write down important personal information, including a family history of heart disease, stroke, high blood pressure or diabetes, and any major stresses or recent life changes.
• Make a list of all medicines, including vitamins or supplements that you're taking. Include dosages.
• Take someone with you, if possible. Someone who goes with you can help you remember information you're given.
• Write down questions to ask your care team.

Prepare a list of questions from most important to least important in case time runs out. For heart arrhythmias, some basic questions to ask your healthcare team include:

• What's the most likely cause of my symptoms?
• Are there other possible causes for my symptoms?
• What kinds of tests will I need? Do I need to do anything to prepare for these tests?
• What's the most appropriate treatment?
• Are there any foods or drinks I should avoid? Is there anything I should add to my diet?
• What's an appropriate level of physical activity?
• How often should I be screened for heart disease or other complications of an arrhythmia?
• I have other health conditions. How can I best manage these conditions together?
• Is there a generic option to the medicine you're prescribing?
• Are there any brochures or other printed material that I can take home with me? What websites do you recommend visiting?

What to expect from your doctor

Your healthcare team is likely to ask you questions, such as:

• When did you first begin having symptoms?
• Do you always have symptoms, or do they come and go?
• How severe are your symptoms?
• Does anything seem to improve your symptoms?
• What, if anything, makes your symptoms worse?
• Does anyone in your family have a heart arrhythmia?