Ventricular fibrillation and tachycardia
Ventricular tachycardia (VT) is a heart rhythm that originates in the ventricles and produces a heart rate of at least 120 beats per minute. It can be thought of as a sequence of consecutive premature ventricular beats. Sometimes, only a few such beats occur together, and then the heart returns to a normal rhythm. If the abnormal heart rhythm lasts more than 30 seconds, it is called sustained ventricular tachycardia. This condition usually occurs in people with a structural heart disorder that has damaged the ventricles. Most commonly it occurs weeks or months after myocardial infarction. It is more common among older people. However, rarely, ventricular tachycardias develop in young people who do not have a structural heart disorder.
People with ventricular tachycardia almost always have palpitations. Sustained ventricular tachycardia can be dangerous because the ventricles cannot fill adequately or pump blood normally. BP tends to fall, and heart failure follows. This condition is also dangerous because it can worsen until it becomes ventricular fibrillation, a form of cardiac arrest.
Sometimes, ventricular tachycardia causes few symptoms, even at rates of up to 200 beats per minute, but it may still be extremely dangerous. ECG is used to diagnose ventricular tachycardias and to help determine whether treatment is required. A portable ECG or Holter monitor may be used to record heart rhythm over a 24-hour period.
Ventricular fibrillation and tachycardia - Animation
Ventricular tachycardia (VT) is a heart rhythm that originates in the ventricles and produces a heart rate of at least 120 beats per minute. It can be thought of as a sequence of consecutive premature ventricular beats. Sometimes, only a few such beats occur together, and then the heart returns to a normal rhythm. If the abnormal heart rhythm lasts more than 30 seconds, it is called sustained ventricular tachycardia. This condition usually occurs in people with a structural heart disorder that has damaged the ventricles. Most commonly it occurs weeks or months after myocardial infarction. It is more common among older people. However, rarely, ventricular tachycardias develop in young people who do not have a structural heart disorder. People with ventricular tachycardia almost always have palpitations. Sustained ventricular tachycardia can be dangerous because the ventricles cannot fill adequately or pump blood normally. BP tends to fall, and heart failure follows. This condition is also dangerous because it can worsen until it becomes ventricular fibrillation, a form of cardiac arrest. Sometimes, ventricular tachycardia causes few symptoms, even at rates of up to 200 beats per minute, but it may still be extremely dangerous. ECG is used to diagnose ventricular tachycardias and to help determine whether treatment is required. A portable ECG or Holter monitor may be used to record heart rhythm over a 24-hour period.
Reviewed By
Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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