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Heart Disease Health Center

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What Are Heart Rhythm Disorders (Arrhythmias)?

Types of Arrhythmias

Heart arrhythmias fall into two categories. One starts from inside the heart’s lower chambers. Doctors call this kind "ventricular" because the lower chambers of the heart are the ventricles. The other kind starts outside or above the ventricle. You may hear these called "supraventricular" arrhythmias.

The most common types of arrhythmia include:

  • Premature atrial contractions. Doctors may call this "PACs" or "APCs." When your heart contracts earlier than expected, it adds an extra heartbeat.
  • Supraventricular tachycardia or paroxysmal SVT. This is when your heart beats rapidly as a result of abnormal electrical impulses above the lower heart chamber.
  • Sick sinus syndrome. This has nothing to do with the sinuses in your head. It’s about your heart’s "SA" node. Your electrical system fires abnormally, causing the rate to go slower than normal.
  • Atrial fibrillation.- This happens when your heart sends electrical impulses at a fast rate that causes a fast and irregular heartbeat
  • Atrial flutter . This comes from your heart misfiring electrical impulses that result in an irregular or fast rhythm.
  • Premature ventricular complex, or PVCs. Your heart fires an abnormal electrical impulse, causing an early heartbeat. Usually, the heart returns to its normal rhythm right away.
  • Ventricular tachycardia. Your heart sends fast impulses and causes a very rapid heart rate. This is usually very serious and calls for immediate medical attention.
  • Ventricular fibrillation.-Electrical impulses arise in a fast and disordered sequence, causing your heart to lose its ability to beat and pump blood. This typically causes a cardiac arrest.
  • Supraventricular arrhythmias. These are more common and are generally temporary and often not serious. They can, though, be uncomfortable.

When to Seek Medical Care

You may have noticed your heart racing, a fluttering in your chest, or a sensation that your heart skipped a beat. If this happens once or infrequently with no other symptoms, it is usually not serious. However, talk to your doctor about your questions and concerns. If you get treatment and it doesn’t help, make sure to let your doctor know.

If you have any of the following symptoms, call 911 immediately: 

  • Any unexplained shortness of breath
  • Light-headedness or feeling faint
  • You feel that your heart is beating too slowly or too quickly
  • Chest pain with any of these symptoms


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