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Symptoms of specific arrhythmias include:

  • Sinus node dysfunction - There may not be any symptoms, or it may cause dizziness, fainting and extreme fatigue.

  • Supraventricular tachyarrhythmias - These can cause palpitations (awareness of a rapid heartbeat), low blood pressure and fainting.

  • Atrial fibrillation - Sometimes, there are no symptoms. This can cause palpitations; fainting; dizziness; weakness; shortness of breath; and angina, which is chest pain caused by a reduced blood supply to the heart muscle. Some people with atrial fibrillation alternate between the irregular heartbeat and long periods of completely normal heartbeats.

  • A-V block or heart block - First-degree A-V block does not cause any symptoms. Second-degree A-V block causes an irregular pulse or slow pulse. Third-degree A-V block can cause a very slow heartbeat, dizziness and fainting.

  • VT - Non-sustained VT may not cause any symptoms or cause a mild fluttering in the chest. Sustained VT usually causes lightheadedness or loss of consciousness and can be lethal.

  • Ventricular fibrillation - This causes absent pulse, unconsciousness and death.

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