Ventricular tachycardia

Ventricular tachycardia (V-tach or VT) is a cardiovascular disorder in which fast heart rate occurs in the ventricles of the heart. Although a few seconds of VT may not result in permanent problems, longer periods are dangerous; and multiple episodes over a short period of time are referred to as an electrical storm, which also occurs when one has a seizure (although this is referred to as an electrical storm in the brain). Short periods may occur without symptoms, or present with lightheadedness, palpitations, shortness of breath, chest pain, and decreased level of consciousness. Ventricular tachycardia may lead to coma and persistent vegetative state due to lack of blood and oxygen to the brain. Ventricular tachycardia may result in ventricular fibrillation (VF) and turn into cardiac arrest. This conversion of the VT into VF is called the degeneration of the VT. It is found initially in about 7% of people in cardiac arrest.

Ventricular tachycardia can occur due to coronary heart disease, aortic stenosis, cardiomyopathy, electrolyte imbalance, or a heart attack. Diagnosis is by an electrocardiogram (ECG) showing a rate of greater than 120 beats per minute and at least three wide QRS complexes in a row. It is classified as non-sustained versus sustained based on whether it lasts less than or more than 30 seconds. The term ventricular arrhythmia refers to the group of abnormal cardiac rhythms originating from the ventricle, which includes ventricular tachycardia, ventricular fibrillation, and torsades de pointes.