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Alternative namesVentricular tachycardia is 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 disruption of normal heartbeat ( 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).
Healed heart attacks evolve to form scar tissue which predisposes to ventricular tachycardia that may occur months after the heart attack. Ventricular tachycardia can also result from anti-arrhythmic medications (an undesired effect) or from altered blood chemistries (such as a low potassium level), pH (acid-base) changes, or insufficient oxygenation.
A common mechanism for ventricular tachycardia is reentry (re-stimulation of the electrical conductive pathway from a single initial stimulus ). 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 a specific variation in the conduction of the ventricular stimulus.
Note: Symptoms may start and stop suddenly. In some cases, there are no symptoms.
Signs and testsVentricular tachycardia can occur in episodes during which the person will have a rapid pulse or the symptoms described above. The blood pressure may be normal or low. Loss of consciousness may occur. Ventricular tachycardia is a potentially lethal arrhythmia and may result in an absent pulse.
Ventricular tachycardia may be seen on:
Blood chemistries and other tests may be performed.
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 may be require CPR , electrical defibrillation or cardioversion (electric shock), or intravenous anti-arrhythmic medications (such as lidocaine, procainamide, bretylium, or sotalol).
Long-term treatment of ventricular tachycardia may require the use of oral anti-arrhythmic medications (such as procainamide, amiodarone, or sotalol). Anti-arrhythmic medications, however, may have severe side effects, and their use is currently decreasing in favor of other treatments.
Some ventricular tachycardias may show in the electrophysiologic study to be suitable for an ablation procedure. Radiofrequency catheter ablation is a curative treatment for selected tachycardias.
In recent years, a preferred treatment for many chronic (long-term) ventricular tachycardias consists of implanting a device called implantable cardioverter defibrillator (ICD). The ICD is implanted usually in the chest, like a pacemaker, and it is connected to the heart with wires.
The ICD is programmed by the doctor to sense ventricular tachycardia when it is occurring, and to administer a shock to abort it. The ICD may also be programmed to send a rapid burst of paced beats to interrupt the ventricular tachycardia. The ventricular tachycardia may require also the use of concomitant anti-arrhythmic agents to prevent repeated firing of the ICD.
Expectations (prognosis)The outcome varies depending on the underlying cardiac disorder, the situation, and symptoms.
ComplicationsVentricular tachycardia may not cause symptoms in some people, but may be lethal in others -- it is a major cause of sudden cardiac death.
Calling your health care providerGo to the emergency room or call the local emergency number (such as 911) if you feel a rapid, irregular pulse, fainting, or chest pain -- all of which may be indicative of ventricular tachycardia.
PreventionIn some cases, the disorder is not preventable. In other cases, treatment of underlying cardiac disorders, correction of blood chemistries, and correction of underlying heart diseases may prevent ventricular tachycardia.
Update Date: 5/2/2002Elena Sgarbossa, M.D., Department of Cardiology, Rush-Presbyterian St. Luke's Medical Ctr., Chicago, IL. Review provided by VeriMed Healthcare Network.
Last updated: Tue, 06 Jan 2009 00:20:03 GMT