An Implantable Cardioverter Defibrillator

(ICD)

An ICD cardioversion or defibrillation the heart in ventricular tachycardia (VT) or ventricular fibrillation (VF). Today’s ICD enable tiered therapy and additionally offer a antibradykardes and anti-tachycardia pacing (atrial or ventricular tachycardia termination) and the storage of intracardiac electrograms.

The need to treat an arrhythmia depends on the symptoms and the risks inherent in this arrhythmia in itself. The therapy is based on the reasons behind any particular arrhythmia. IIm necessary, it may be necessary a direct antiarrhythmic therapy with anti-arrhythmic drugs, cardioversion, defibrillation, implantable cardioverter-defibrillators (ICDs), pacemaker (and a special form of “pacing”, cardiac resynchronization therapy), or a combination of these forms of therapy. An ICD cardioversion or defibrillation the heart in ventricular tachycardia (VT) or ventricular fibrillation (VF). Today’s ICD enable tiered therapy and additionally offer a antibradykardes and anti-tachycardia pacing (atrial or ventricular tachycardia termination) and the storage of intracardiac electrograms. An ICD is implanted subcutaneously or subpectorally. The electrodes are transvenous right ventricular and sometimes placed in the right atrium. In a bi-ventricular ICD also a left ventricular epicardial electrode via the venous system of the coronary sinus or via a thoracotomy is placed. The indication for implantation of an ICD is given to patients with episodes of ventricular fibrillation or hemodynamically significant ventricular tachycardia that is not due to reversible or transient causes (eg. As electrolyte abnormalities, proarrhythmia by antiarrhythmic drugs or acute myocardial infarction) were triggered. The implantation of an ICD may be indicated in patients where during an electrophysiological examination ventricular tachycardia or ventricular fibrillation could be triggered, or in patients with idiopathic or ischemic cardiomyopathy, left ventricular ejection fraction of <35% and a high risk of ventricular tachycardia or fibrillation to develop. Other indications for implantation of an ICD are less clear (see table: Indications for implantable cardioverter defibrillators for ventricular tachycardia and ventricular fibrillation). An ICD is used rather than the treatment of prophylaxis of ventricular tachycardia or fibrillation. Therefore, patients may need with a tendency to ventricular tachycardia or fibrillation, a combination of an ICD and a Antiarrhythmikatherapie to reduce the number of arrhythmic attacks and the need to unpleasant electric shocks. Also, the functional life of the ICD is prolonged. The aggregate of an ICD usually has a term of office of five years. Among the disorders include inadequate delivery of pacing or shocking pulses in normal sinus rhythm, supraventricular tachycardia or not physiologically generated pulses (z. B. due to a defective electrode). Another disorder is non-delivery of pacing or shock pulses when they are necessary because of factors such. B. displacement of the electrode or of the pulse generator, undersensing, stimulation threshold rise due to fibrosis at the site of previous shocks and empty batteries. If patients report that the ICD has become flat, but that no accompanying symptoms of syncope, dyspnea, chest pain or persistent palpitations have occurred, a check at the clinic and / or when electrophysiologists within a week is appropriate. The ICD can then be electronically scanned to determine the reason for the discharge. If such anomalies occur, or the patient has received several shocks (coronary ischemia, electrolyte abnormality z. B.) or a malfunction of the unit should be searched for presentation to the emergency room after a treatable cause. Indication for implantable cardioverter defibrillators in ventricular tachycardia and ventricular fibrillation level of evidence Specific indications (evidence-based) hemodynamically unstable ventricular tachycardia or ventricular fibrillation, if no temporary or reversible cause exists stable hemodynamic, sustained ventricular tachycardia in patients with structural heart disease syncope unknown origin with hemodynamically significant, sustained ventricular tachycardia or ventricular fibrillation induced during an electrophysiological examination Ischemic cardiomyopathy, symptoms of heart failure according to NYHA class II, or III with optimal medical Be treatment and left ventricular ejection fraction of ? 0.35, as measured at least 40 days after myocardial infarction Ischemic cardiomyopathy, NYHA Class I heart failure symptoms with optimal medical therapy and LV ejection fraction ? 30% measured at least 40 days after myocardial infarction Ischemic cardiomyopathy, symptoms of heart failure according to NYHA class II or III heart failure symptoms with optimal medical treatment and left ventricular ejection fraction of ? 0. 35 Ischemic cardiomyopathy, non-sustained ventricular tachycardia, ventricular ejection fraction ? 40%, as measured at least 40 days after a myocardial infarction and inducible ventricular fibrillation or sustained ventricular tachycardia detected, Maybe indziert during an electrophysiological study, supported by a Much of the evidence patients with idiopathic dilated cardiomyopathy, significant left ventricular dysfunction with optimum medical treatment, with unexplained syncope patients with sustained ventricular tachycardia and normal or near normal cardiac function patients with hypertrophic cardiomyopathy with one or more high-risk factors apart from sustained ventricular tachycardia / ventricular fibrillation (family history of premature , sudden death, unexplained syncope, left ventricular septal thickness ? 30 mm, abnormal blood pressure response during exercise, non-sustained ventricular tachycardia) patients with arrhythmogenener right ventricular cardiomyopathy with one or more high risk factors apart from sustained ventricular tachycardia / ventricular fibrillation (extensive disruption of the right ventricle affected and suddenly deceased family member diagnosed syncope, non-sustained ventricular tachycardia, inducible ventricular tachycardia detected during an electrophysiological examination) long QT syndrome, syncope or ventricular tachycardia while taking a beta blocker non-hospitalized patients waiting for a heart transplant Brugada syndrome and syncope or documented ventricular tachycardia not lead to a cardiac arrest has indexed with catecholaminergic, polymorphic ventricular tachycardia with syncope and / or documented sustained ventricular tachycardia while taking a beta-blocker patients with cardiac sarcoidosis, Giant Cell, or Chagas disease may patients but less well supported by evidence patients with idiopathic cardiomyopathy , symptoms of heart failure after NYH A class I with optimal medical treatment, left ventricular ejection fraction ?0,35 patients with Long QT Syndrome without syncope or ventricular tachycardia with one or more high risk factors (QTc> 0.5 s, LQT1 with 2 copies of the abnormal abnormal genes and numbness [formerly Jervell-Lange-Nielsen syndrome], LQT2, LQT3) patients with syncope and an advanced structural heart disease when no cause could be identified by invasive and non-invasive investigations patients with familial cardiomyopathy, associated with sudden death patients with left ventricular noncompaction Not indicated syncope of unknown etiology in the absence of inducible ventricular tachycardia, ventricular fibrillation and without structural heart disease resistant ventricular tachycardia o the ventricular fibrillation Ventricular tachycardia or fibrillation with mechanisms that are accessible to catheter ablation or surgical ablation Ventricular tachycardia or ventricular fibrillation due to temporary or reversible interruptions when a correction is possible and likely recurrence avoids Psychiatric disorders that may worsen by ICD implantation, or a follow-up to exclude patients without reasonable chance of survival with an acceptable functional status for ? 1 year patients with drug-resistant symptoms of Hertz insufficiency NYHA class IV, which are not candidates for a heart transplant or the implantation of a CRT / ICD device ARVC = arrhythmogenene right ventricular cardiomyopathy; CRT = cardiac resynchronization therapy; HCM = hypertrophic cardiomyopathy; ICD = implantable cardioverter defibrillator; LQT1 = Long QT syndrome type 1; LQT2 = Long QT syndrome type 2; LQT3 = Long QT syndrome type 3; LV = left ventricular; NYHA = New York Heart Association; QTc = corrected QT interval; RV = right ventricular; VF = ventricular fibrillation; VT = ventricular tachycardia. Adapted from Epstein AE, DiMarco JP, elbow KA, et al: 2012 ACCF / AHA / HRS focused update incorporated into the ACCF / AHA / HRS 2008 Guidelines for device-based therapy of cardiac rhythm abnormalities. Circulation 127 (3): E283-E352,, 2013.

Health Life Media Team

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