cardiovascular disorders
Ventricular Tachycardia (VT)
Treatment of Ventricular Tachycardia
Acute: Sometimes synchronized direct current cardioversion, sometimes class I or class III antiarrhythmics Long-term: Usually an implantable cardioverter-defibrillator Treatment of acute ventricular tachycardia depends on symptoms and duration of VT. requires Defibrillation with can be treated with Direct Current (DC) Cardioversion-Defibrillation with Stable sustained VTcan also be treated with intravenous class I or class III antiarrhythmic drugs (see table).Lidocaineacts quickly but is frequently ineffective. Iflidocaineis ineffective, IVprocainamidemay be given, but it may take up to 1 hour to work. IVamiodaroneis frequently used but does not usually work quickly. Failure of IVprocainamideor IVamiodaroneis an indication for cardioversion. Nonsustained VTdoes not require immediate treatment unless the runs are frequent or long enough to cause symptoms. In such cases, antiarrhythmics are used as for sustained VT. The primary goal is preventing sudden death, rather than simply suppressing the arrhythmia. It is best accomplished by use of an Implantable Cardioverter-Defibrillators (ICD) (ICD). However, the decision about whom to treat is complex and depends on the estimated probability of life-threatening VTs and the severity of underlying heart disorders (see table Long-term treatment is not required when the index episode of ventricular tachycardia resulted from a transient cause (eg, during the 48 hours after onset of myocardial infarction) or a reversible cause (acid-base disturbances, electrolyte abnormalities, proarrhythmic drug effect). In the absence of a transient or reversible cause, patients who have had an episode of sustained VT typically require an ICD. Most patients with sustained VT and a significant structural heart disorder should also receive a beta-blocker. If an ICD cannot be used,amiodaronemay be the preferred antiarrhythmic for prevention of sudden death. Because nonsustained VT is a marker for increased risk of sudden death in patients with a structural heart disorder, such patients (particularly those with an ejection fraction<0.35) require further evaluation. Such patients should receive an ICD. When prevention of VTs is important (usually in patients who have an ICD and are having frequent episodes of VT), antiarrhythmics or transcatheter or surgical Ablation for Cardiac Arrhythmia of the arrhythmogenic substrate is required. Any class Ia, Ib, Ic, II, or III Transcatheter Ablation for Cardiac Arrhythmia is used most commonly in patients who have VT with well-defined syndromes (eg, right ventricular outflow tract VT or left septal VT [Belhassen VT, 