An arrhythmia is a problem with the rate or rhythm of the heartbeat. The heart may beat too fast, too slowly or irregularly. Some rhythm changes are harmless, while others need medical assessment.
Common Symptoms
- Palpitations or a racing, fluttering or skipping heartbeat
- Dizziness or lightheadedness
- Shortness of breath
- Chest discomfort
- Unusual tiredness or weakness
- Fainting or near-fainting
Types of Arrhythmia
Tachycardia means a heart rate that is faster than expected. Bradycardia means a heart rate that is slower than expected. A slow resting heart rate can be normal in some healthy people but may require assessment when it causes symptoms.
Atrial fibrillation is a common arrhythmia in which the upper chambers of the heart beat irregularly.
Diagnosis
Assessment may include an electrocardiogram, blood tests, ambulatory heart monitoring, an echocardiogram or other cardiac tests. Longer monitoring may be useful when symptoms come and go.
Treatment
Treatment depends on the type of arrhythmia, its cause and the risk of complications. Options can include medication, treatment of an underlying condition, cardioversion, catheter ablation, a pacemaker or an implantable cardiac device.
When to Get Urgent Help
Seek urgent medical help for severe or persistent chest pain, severe breathing difficulty, collapse, loss of consciousness, or new palpitations accompanied by fainting or marked dizziness. Use your local emergency medical service when symptoms are severe or life-threatening.
Related Topics
Sources and Further Reading
Last reviewed: 4 September 2026. This information does not replace individual medical assessment or treatment.