The heart has its own electrical system to regulate how the heart beats. An abnormal change in the rate or pattern of the heartbeat is called an arrhythmia. It can cause the heart to move blood less efficiently. Four chambers hold blood as it moves through the heart. The two lower chambers of the heart are called ventricles. Problems with the signals in the heart can make the ventricles beat faster than normal.

Ventricular Tachycardia (VT)

Too many electrical signals may make the heart beat very fast. This is called tachycardia.
  • With VT, abnormal electrical pathways or circuits form in the ventricles. This usually occurs in a part of the heart that’s damaged by a heart attack or heart disease.
  • Electrical signals enter the abnormal circuit and loop around. With each loop, the signal tells the ventricles to contract. This makes the heart beat very fast.
  • In some cases, VT develops into ventricular fibrillation. This is the most serious type of arrhythmia.

Ventricular Fibrillation (VF)

At times, electrical signals may be sent so fast and unevenly that the heart muscle quivers and doesn’t beat at all. This is called fibrillation.
  • With VF, the ventricles contain many abnormal circuits. These usually form in damaged heart muscle.
  • Signals caught in the circuits make the ventricles beat very quickly and unevenly. This keeps the heart muscle from pumping properly.
  • The heart can get to the point that it can’t pump at all. This is called cardiac arrest. Death may occur if emergency treatment isn’t given to return the heart rhythm to normal.

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