Ventricular tachycardia

Causes and Risks:
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.

Prevention:
In some cases, the disorder is not preventable. In other cases, treatment of underlying cardiac disorders, correction of blood chemistries , and correction of pH and oxygenation problems may prevent ventricular tachycardia. Antiarrhythmic medications may be given to prevent ventricular tachycardia.

Symptoms:

Note: Symptoms may start and stop suddenly. In some cases, there are no symptoms. Decreased urine output may also be associated with this disease.

Signs and Tests:
Ventricular tachycardia can exist as a potentially lethal arrhythmia , resulting in an absent pulse . It can also exist as a stable form, in which case the person will have a rapid pulse . The blood pressure is normal or low.

Ventricular tachycardia may be seen on:

Blood chemistries and other tests may be performed.

Treatment:
Treatment varies with the symptoms, the situation, and the underlying cardiac disorder. No treatment may be required in some cases.

Ventricular tachycardia may become an emergency situation and CPR may be required. Electrical defibrillation or cardioversion (electric shock) may be needed.

Antiarrhythmic medications such as lidocaine, procainamide, and others may be helpful in controlling ventricular tachycardia. Medications may also include beta-blockers, amiodarone, or others.

Cardiac surgery may be indicated in some cases.

Implanted devices such as an AICD (automatic implanted cardiac defibrillator, an implanted device that senses ventricular tachycardia and administers a shock) may be useful for controlling chronic ventricular tachycardia.

Prognosis:
The outcome varies depending on the underlying cardiac disorder, the situation, and symptoms.

Complications:
Ventricular tachycardia may not cause symptoms in some people; it may cause sudden death in others.

Call Your Healthcare Provider:
Go to the emergency room or call the local emergency number (such as 911) if chest pain or other symptoms of ventricular tachycardia occur.