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Heart Disease Health Center

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When Your Heart Rhythm Isn't Normal

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Causes and Types of of Arrhythmias continued...

AV nodal reentrant tachycardia. This is another type of fast heartbeat. It's caused by there being an extra pathway through a part of the heart called the AV node. It can cause heart palpitations, fainting, or heart failure. In some cases, you can stop it simply by breathing in and bearing down. Some drugs can also stop this heart rhythm.

Ventricular tachycardia (V-tach). A rapid heart rhythm starting from the heart's lower chambers. Because the heart is beating too fast, it can't fill up with enough blood. This can be a serious arrhythmia -- especially in people with heart disease -- and it may be linked to other symptoms.

Ventricular fibrillation. This happens when the heart's lower chambers quiver and can't contract or pump blood to the body. This is a medical emergency that must be treated with CPR and defibrillation as soon as possible.

Long QT syndrome. This may cause potentially dangerous arrhythmias and sudden death. Doctors can treat it with medications or devices called defibrillators.

Bradyarrhythmias. These are slow heart rhythms, which may be due to disease in the heart's electrical system. If you experience this, call your doctor.

Sinus node dysfunction. This slow heart rhythm is due to a problem with the heart's sinus node. Some people with this type of arrhythmia need a pacemaker.

Heart block. There is a delay or a complete block of the electrical impulse as it travels from the heart's sinus node to its lower chambers. The heart may beat irregularly and, often, more slowly. In serious cases, you'd get a pacemaker.

Symptoms of Arrhythmias

An arrhythmia can be silent, meaning you don't notice any symptoms. A doctor can find an irregular heartbeat during a physical exam by taking your pulse or through an electrocardiogram (ECG or EKG).

If you do have symptoms, they may include:

  • Palpitations (a feeling of skipped heart beats, fluttering or "flip-flops")
  • Pounding in your chest
  • Dizziness or feeling light-headed
  • Fainting
  • Shortness of breath
  • Chest pain or tightness
  • Weakness or fatigue (feeling very tired)
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