In a volley of ? 3 consecutive beats at a frequency of ? 120 beats / min is called a ventricular tachycardia (VT). Symptoms depend on the duration and vary from asymptomatic for palpitations to hemodynamic collapse and death. The diagnosis results from the ECG. The therapy for more than just short attacks is according to symptoms of the cardioversion or drug treatment with antiarrhythmic drugs. If necessary, for long-term therapy, an implantable cardioverter defibrillator (ICD) is used.
Some experts speak of a ventricular tachycardia when the frequency is ? 100 beats / min. They are usually benign and must be treated only if they show hemodynamic effects. Repeated ventricular rhythms at a slower frequency are called accelerated idioventricular rhythms or slow VT.
In a volley of ? 3 consecutive beats at a frequency of ? 120 beats / min is called a ventricular tachycardia (VT). Symptoms depend on the duration and vary from asymptomatic for palpitations to hemodynamic collapse and death. The diagnosis results from the ECG. The therapy for more than just short attacks is according to symptoms of the cardioversion or drug treatment with antiarrhythmic drugs. If necessary, for long-term therapy, an implantable cardioverter defibrillator (ICD) is used. Some experts speak of a ventricular tachycardia when the frequency is ? 100 beats / min. They are usually benign and must be treated only if they show hemodynamic effects. Repeated ventricular rhythms at a slower frequency are called accelerated idioventricular rhythms or slow VT. In most cases, at a VT significant heart disease, v. a. a previous myocardial infarction and cardiomyopathy. Also electrolyte derailments (v. A. Hypokalemia and hypomagnesemia), acidemia, hypoxemia and drug side effects may cause a VT. The long QT syndrome (congenital or acquired) is a particular form of VT, the torsades de pointes tachycardia associated. VT may be monomorphic or polymorphic, temporary or lasting. The monomorphic VT: A single abnormal focus or reentrant pathway and regular, uniform translucent QRS complexes The polymorphic VT: Several different foci or pathways and irregular, varying QRS complexes not sustained VT. Lasts <30 sec Sustained VT takes ? 30 seconds or more is terminated due to a hemodynamic collapse. VT often goes into ventricular fibrillation and lead to cardiac arrest. Symptoms and complaints Ventricular tachycardia short-lived or slower frequency may be asymptomatic. A sustained VT is almost always symptomatic with palpitations, hemodynamic problems or sudden death. Diagnostic ECG diagnosis of ventricular tachycardia is performed by ECG (ventricular tachycardia with a wide QRS complex.). Each tachycardia with wide QRS complexes (QRS ? 0.12 s) should be subject to proof to the contrary regarded as ventricular. The diagnosis is supported by the ECG picture. Here, an independent P-wave activity, fusion or capture complexes, conformity of the QRS vector in the precordial leads show (Concordance) having a discordance of the T wave (the opposite QRS vector) and a QRS-axis in the northwest quadrant in the frontal plane. The differential diagnosis can be excluded, a supraventricular tachycardia, which is transferred with a branch block or via an accessory pathway (see Table: Modified Brugada criteria for ventricular tachycardia.). Some patients tolerate VT amazingly well. However, To draw the conclusion that it is in a well-tolerated by patients tachycardia with wide QRS complexes around a tachycardia supraventricular origin, is a mistake. Drugs like verapamil or diltiazem, which are suitable for termination of supraventricular tachycardia, can lead to a VT to a hemodynamic collapse and death in patients. Ventricular tachycardia with a wide QRS complex. The QRS duration is 160 ms. Lead II is an independent P-wave shows. (Arrows). There is a type of location shift of the middle frontal axis to the left. Treating acute therapy: Sometimes synchronized Gleichstromkardioversion, sometimes antiarrhythmic agents of Class I or III long-term therapy: usually insertion of an implantable cardioverter defibrillator (ICD). Acute Treatment Treatment of acute ventricular tachycardia depends on the symptoms and the duration of VT. A VT with hypotonic circulatory conditions requires a synchronized Gleichstromkardioversion with ?100 joules. Stable, sustained VT can be treated intravenously with drugs of the class I or with drugs Class III (see table: antiarrhythmics (Vaughan-Williams classification)). Lidocaine acts quickly, but is often ineffective. Remains the treatment with lidocaine unsuccessful, procainamide can i.v. are given. (N. D. Talk .: amiodarone iv is now the drug therapy of choice.) Here, however, it can take up to an hour before an effect is shown. iv Amiodarone is often used, but does not work usually fast. If the VT with procainamide or amiodarone iv not terminated, there is an indication for cardioversion. A non-sustained VTmuss are not treated immediately when the attacks become more frequent and last for so long that symptoms appear. In such cases, drug therapy is the same as in the ongoing VT.Langzeittherapie The primary goal of therapy is rather the prevention of sudden cardiac death than mere suppression of arrhythmia. For this is best, an implantable cardioverter defibrillator (ICD). Deciding which patients need an ICD is complex and depends on the adopted as a likely risk of a life-threatening VT and the severity of heart disease underlying (see table: Indications for implantable cardioverter defibrillators for ventricular tachycardia and ventricular fibrillation). Long-term therapy is not required if the index episode of VT due to a temporary cause (eg., During the first 48 h after myocardial infarction) or by a reversible cause z. B. (disturbances in the acid-base balance, electrolyte derailments proarrhythmic acting drugs) was triggered. There are no temporary or reversible causes need before, patients who had an episode of sustained VT, usually an ICD. In the presence of sustained VT in combination with a significant structural heart disease a beta-blocker should be given in addition. If the use of ICD impossible, amiodarone is the antiarrhythmic drug of choice to prevent sudden cardiac death. Since a non-sustained VT patients is a signal of an increased risk of sudden cardiac death with a structural heart disease, these patients require (v. A. At an ejection fraction <0.35) a further medical judgment. Such patients, an ICD should be used. To avoid ventricular tachycardia (usually important in patients with ICD and frequent VT episodes) therapy with antiarrhythmic drugs, transvenous RF catheter ablation or surgical ablation of the arrhythmogenic substrate is required. For drug treatment, each antiarrhythmic agent of class Ia, Ib, Ic, II or III is suitable. Beta blockers are reliable and therefore, unless contraindicated, drugs of first choice. Is an additional drug is required, sotalol is usually added, then amiodarone. The transvenous RF catheter ablation is performed frequently in otherwise healthy patients heart with a VT with a well defined syndrome (z. B. right ventricular or left ventricular Ausflusstrakttachykardie fascicular tachycardia [Belhassen tachycardia, verapamilsensitive tachycardia]). Summary Each tachycardia with wide QRS complexes (QRS ? 0.12 s) should be proof to the contrary considered as ventricular. In unstable patients (z. B. with hypotension, chest pain) should be a Gleichstromkardioversion with ? 100 joules be performed. If the patient is stable, the administration of lidocaine iv, iv procainamide Amiodarone or iv be tried. Patients who suffered a series of sustained VT without temporary or reversible reason usually require an ICD.