Ventricular tachycardia

VT, Torsade de Pointes, Paroxysmal Ventricular Tachycardia

What is ventricular tachycardia?

Ventricular tachycardia (VT) is a serious arrhythmia (abnormal heart rhythm) in which the heartbeat is initiated in the ventricles (lower heart chambers) rather than from the sinoatrial node in the right atrium (upper heart chamber). As a result, the heartbeats at an abnormally fast rate of 140 to 220 beats per minute. VT is either sustained (lasting up to several days) or non-sustained (lasting 30 seconds or less). Ventricular tachycardia occurs most often in individuals with pre-existing heart disease such as mitral valve prolapse, congenital heart disease, ischemic heart disease (insufficient oxygen to the heart muscle), or cardiomyopathy (disease of the heart muscle). Ventricular tachycardia can also follow an acute myocardial infarction (heart attack), or as a result of drug toxicity. Torsade de pointes, a form of ventricular tachycardia associated with drug toxicity, has an abrupt onset and a poor prognosis.

How is it diagnosed?

Symptoms of Ventricular tachycardia

Ventricular tachycardia may have no symptoms at all (asymptomatic). However, most individuals present with light-headedness, weakness, chest discomfort, shortness of breath, palpitations (sensation of the heart beating rapidly or intensely), abrupt loss of consciousness (syncope), or seizures.

Physical exam may reveal a pulse that is weak, rapid or nonpalpable (cannot be felt). There may be inconsistencies in the blood pressure or muffled heart sounds. The individual may appear anxious, agitated, or lose consciousness.

Tests: Diagnosis is confirmed by an electrocardiogram (EKG). This record of the electrical activity of the heart will show broad, abnormal waves.

How is it treated?

Individuals who have non-sustained ventricular tachycardia but have no structural heart disease (no damage to the heart muscle) or symptoms may not require drug treatment. Underlying metabolic abnormalities or cardiac disorders must be treated. If the ventricular tachycardia is due to a drug toxicity, the drug is discontinued.

Sustained ventricular tachycardia is treated initially with antiarrhythmic drugs. If a normal rhythm is not restored quickly with drugs, cardioversion (administration of an electric shock to the heart) may be required. Striking the person's chest (thump conversion) may also be used if onset is observed. Once cardioversion occurs, the antiarrhythmic drug is usually continued for several months. The treatment of individuals with chronic, recurrent ventricular tachycardia is controversial. Drugs and/or implantable cardiac defibrillators may be used. Drugs, pacemakers, or surgical techniques may be used to prevent recurrences.

Medications

Tenormin (Atenolol), Cordarone (Amiodarone), Betapace (Sotalol)

What might complicate it?

Complications include progression to ventricular fibrillation, hypotension, shock, congestive heart failure, and death.

Predicted outcome

Prognosis depends on the type and degree of underlying heart disease. The outcome is good for individuals who experience ventricular tachycardia as a one-time experience. Complete recovery without lasting adverse reactions may be expected if there is no serious underlying heart disease. Close monitoring of drug therapy in individuals with recurrent episodes usually prevents progression to ventricular fibrillation and death.

Alternatives

Supraventricular tachycardia and aberration is a condition similar to ventricular tachycardia. EKG and rhythm strip may need expert interpretation to differentiate.

Appropriate specialists

Cardiologist and cardio-thoracic surgeon.

Last updated 23 June 2011


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