Heart Rhythm Disorders / Arrhythmia

The heart beats because of regular electrical signals. These signals start in the sinus node, the natural pacemaker in the right upper chamber (right atrium), then travel through the atrioventricular node (the junction between the upper and lower chambers) to both lower chambers (ventricles). In adults at rest, a normal heart rate is usually 60 to 100 beats per minute with a regular rhythm. An arrhythmia occurs when the formation or conduction of these signals is disrupted.

Types of Arrhythmia

Arrhythmias are grouped by their speed and where they start. Tachycardia is a heartbeat that is too fast, more than 100 beats per minute at rest, covered on the Tachycardia page. Bradycardia is a heartbeat that is too slow, covered on the Bradycardia page. There are also irregular rhythms from the upper chambers, namely atrial fibrillation and atrial flutter, as well as ventricular fibrillation from the lower chambers, which causes cardiac arrest. Tachycardia-bradycardia syndrome combines fast and slow heartbeats that alternate, while post-procedural arrhythmia appears after heart surgery or a heart procedure. The full list is shown in the condition types section on this page.

Why Arrhythmias Happen

The causes vary. Some are related to heart disease, such as coronary artery disease, scarring from a previous heart attack, valve problems, or a weakened heart muscle. Others are triggered by conditions outside the heart, for example an overactive thyroid gland, unbalanced potassium or magnesium levels, pauses in breathing during sleep (sleep apnea), medication side effects, alcohol, or lack of sleep. Some arrhythmias also run in families because of gene changes that control the heart's electrical activity.

Not All Arrhythmias Are Dangerous

Occasional extra beats, such as premature contractions, are common in healthy people and usually do not need treatment. On the other hand, atrial fibrillation increases the risk of stroke, severe bradycardia can make you faint, and arrhythmias from the lower chambers can stop the heart from pumping. For this reason, the first step is to confirm the type of arrhythmia with a recording of the heart rhythm, rather than guessing from symptoms alone.

Treatment is tailored to the type of arrhythmia, your symptoms, and your heart condition. Options range from addressing triggers, medication, and catheter ablation to implanting a pacemaker or an ICD. Many people with arrhythmias can continue to work, exercise, and go about their usual activities once their treatment is clear.

The key to diagnosing an arrhythmia is recording the heart rhythm right when symptoms occur. The doctor starts by asking what the palpitations feel like, when they occur, how long they last, and what triggers them, as well as about the medications you take and your family history. If you were able to check your pulse or record your rhythm with a smartwatch during symptoms, bring the record with you.

A resting ECG is done at the first visit. If the arrhythmia only appears occasionally, the doctor uses longer recordings, from a 24 to 48 hour Holter monitor and a patch recorder worn for several days to an implanted recorder for symptoms that occur rarely. Echocardiography and blood tests help look for the cause behind the arrhythmia. In certain cases, an electrophysiology study is done to map the source of the arrhythmia from inside the heart.

Make an appointment with a cardiologist if you often feel unusual palpitations, especially if they come with dizziness, tiring easily, or shortness of breath. A checkup is also recommended if your pulse feels irregular or very slow without a clear reason, or if your smartwatch repeatedly warns of an irregular rhythm.

Go to the emergency room right away or call emergency services if:

• You faint or nearly faint, especially during activity
• Palpitations come with chest pain, severe shortness of breath, or a cold sweat
• A very fast heartbeat does not stop after a few minutes and you feel weak
• Signs of stroke appear, such as a drooping face, slurred speech, or weakness on one side of the body
• Someone suddenly becomes unresponsive and is not breathing normally: start chest compressions and ask someone else to find an AED