The heart does more than pump blood throughout the body. It also has its own electrical system that controls when and how the heart contracts.

Normally, an electrical impulse begins in the sinus, or sinoatrial, node in the right atrium. The signal travels through the heart in an organized sequence, allowing its chambers to contract efficiently and pump blood throughout the body. In healthy adults, a resting heart rate is generally between 60 and 100 beats per minute.

What Is an Arrhythmia?

An arrhythmia is a problem with the rate or rhythm of the heartbeat. It occurs when the electrical signals that coordinate the heartbeat are generated or transmitted abnormally.

As a result, the heart may beat too fast, too slowly, or irregularly. A fast heart rhythm is referred to as tachycardia, while an unusually slow rhythm is known as bradycardia. Another common rhythm disorder is atrial fibrillation, or AFib, in which abnormal electrical activity causes the upper chambers of the heart to beat irregularly.

Symptoms to Watch For

Some arrhythmias cause no noticeable symptoms and may only be detected during a routine medical examination.

When symptoms do occur, they may include a fluttering, pounding, or racing heartbeat, an unusually slow heartbeat, fatigue, dizziness, shortness of breath, or chest discomfort. In some cases, a person may feel faint or lose consciousness.

What Can Increase the Risk?

Several conditions can increase the likelihood of developing an abnormal heart rhythm, including heart disease, high blood pressure, diabetes, thyroid disorders, sleep apnea, electrolyte abnormalities, and increasing age.

Certain medicines and lifestyle factors may also influence heart rhythm. Stress, smoking, excessive alcohol intake, and stimulant use may trigger arrhythmias in susceptible individuals.

Caffeine may trigger palpitations or abnormal rhythms in some people, particularly when consumed in excessive amounts. Individual responses vary, however, so symptoms should be evaluated in the context of a person's overall health and risk factors.

How Is an Arrhythmia Diagnosed?

An electrocardiogram, or ECG/EKG, is the most commonly used test for diagnosing an arrhythmia because it records the heart's electrical activity.

If an abnormal rhythm occurs intermittently and is not captured during a standard ECG, a healthcare provider may recommend longer-term monitoring with a Holter monitor or another portable heart rhythm recorder. Blood tests may also be performed to check electrolytes and thyroid hormone levels when appropriate.

Recognizing changes in your heartbeat is important, particularly when palpitations repeatedly occur together with fatigue, dizziness, breathing difficulty, or chest discomfort. Chest pain, severe shortness of breath, or fainting requires immediate medical evaluation.