Arrhythmias are abnormal or irregular heartbeats. They occur when the electrical impulses in your heart coordinate the natural rhythm incorrectly.

Most people have experienced an arrhythmia. However, you may have had an arrhythmia without any symptoms. Your doctor may be the first to notice signs of an arrhythmia. This will probably be during a routine physical exam when they listen to your heartbeat or perform an electrocardiogram (ECG).

Symptoms of arrhythmias are varied and can indicate either a harmless condition or one that needs immediate attention. To be safe, you should consult your doctor if you have any of these symptoms.

The most common signs and symptoms of arrhythmias include:

  • a feeling that your heart is skipping a beat
  • a heartbeat that is too fast or “racing”
  • a heartbeat that is too slow
  • an irregular heartbeat
  • pauses between heartbeats

More serious symptoms include:

  • chest pain
  • shortness of breath
  • dizziness
  • lightheadedness
  • fainting or near-fainting
  • severe heart palpitations
  • anxiety
  • sweating

The symptoms of arrhythmias are too often ignored. You should always consult your doctor if you have symptoms of arrhythmias. Some symptoms signal a need for immediate care. Additionally, some symptoms may be caused by other problems that require urgent diagnosis.

The following arrhythmias are medical emergencies. They must be treated as soon as possible. If left untreated, they can damage your heart or brain, or even cause death.

Supraventricular arrhythmias

Supraventricular arrhythmias cause a fast heart rate. They require immediate emergency care.

  • Atrial fibrillation – This is the most common supraventricular arrhythmia. It occurs when the atria have fast and irregular contractions. This arrhythmia can cause a stroke or heart failure. Treatment will include medications, nonsurgical procedures, or surgery.
  • Atrial flutter – This type of arrhythmia is very similar to atrial fibrillation. Its main distinction is that it has a regular contraction cycle (rhythm). This type of arrhythmia is very uncommon.
  • Wolff-Parkinson-White (WPW) syndrome – This is a life-threating type of arrhythmia that causes the ventricles to contract prematurely. It occurs when an extra electrical pathway disrupts the timing of your heartbeat.

Ventricular arrhythmias

These arrhythmias start in the ventricles and usually require immediate medical care.

  • Ventricular tachycardia – This arrhythmia has a fast heartbeat and lasts for only a few seconds. Any duration longer than a few seconds is dangerous and requires emergency medical care.
  • Ventricular fibrillation – V-fib is a very serious condition that can lead to sudden cardiac arrest and death. It occurs when electrical signals in the heart become disorganized. As a result, the ventricles quiver rather than pump normally. Without blood being pumped through the body, this will lead to sudden cardiac arrest. The impulses can be corrected using a defibrillator. In some cases, an implantable defibrillator may be required for long-term care.


The main symptom of this arrhythmia is a slow heartbeat. The body relies on consistent blood flow, so a slow heartbeat can be a serious problem. If the brain doesn’t get enough blood, it may lead to unconsciousness. A slow heart rate may not be a problem for people who are fit. But in others, it can cause a serious condition like a heart attack, chemical imbalance, or an underactive thyroid gland.