Ventricular tachycardia

Alternative names:

V tach; wide-complex tachycardia

Definition:

A rapid heart beat initiated within the ventricles, characterized by 3 or more consecutive premature ventricular beats.

Causes, incidence, and risk factors:

Ventricular tachycardia is a potentially lethal arrhythmia that may cause the heart to become unable to pump adequate blood through the body. The heart rate may be 160 to 240 (normal is 60 to 100 beats per minute) and is regular.

Ventricular tachycardia can occur spontaneously. It can also develop as a complication of a heart attack (rare in children), cardiomyopathy, mitral valve prolapse, myocarditis, and after heart surgery. It may be a result of scar tissue formed after an earlier heart attack, or an undesired effect of antiarrhythmic drugs. It may be triggered by disrupted blood chemistries (such as a low potassium level), pH (acid-base) changes, or insufficient oxygenation. Reentry (restimulation of the electrical conductive pathway from a single initial stimulus) may be a mechanism seen in ventricular tachycardia.

Ventricular tachycardia is classified as nonsustained (often defined as lasting less than 30 seconds) or sustained. Torsade de pointes is a form of ventricular tachycardia with characteristic variation in the conduction of the ventricular stimulus.

Ventricular tachycardia occurs in approximately 2 out of 10,000 people.