Defibrillation systems

Ventricular fibrillation should be terminated by electrical defibrillation. Alternatively, lidocaine can be injected intravenously. In cases with lower frequency, ventricular tachyarrhythmia class I diugs such as aj marine, flecainide or propafenone are more effective as a result of the use-dependence of lidocaine. For prophylaxis treatment, amiodarone or sotalol may be helpful or the implantation of a cardioverter-defibrillator system. Acute amiodarone (i.v. in higher doses) can also terminate ventricular tachyarrhythmias. This action, however, seems to be mediated by its INa-blocking side effects and not (or less) by its class III like effects. 

Duray GZ, Israel CW, Pajitnev D, Hohnloser SH. Upgrading to biventricular pacing/defibrillation systems in right ventricular paced congestive heart failure patients prospective assessment of procedural parameters and response rate. Europace 2008 10 48-52. 

Defibrillator systems apply electrical shocks through two electrodes attached to the heart. Current analyses specify power needs at 10"3 W (continuous) and 1 W peak power for developing a sufficient shock. The estimates show that current lithium batteries will be depleted after 100 shocks and need to be replaced every 2 to 3 years. 

Korley VJ, Hallet N, Daoust M, Epstein LM (2000) A novel indication for transvenous lead extraction upgrading implantable cardioverter defibrillator systems. J Interv Card Electrophysiol 4(3) 523-528... 

Pfitzner P, Trappe HJ (1998) Oversensing in a cardiac defibrillator system caused by interaction between two endocardial defibrillation leads in the right ventricle. Pacing Clin Electrophysiol 21 764-768... 

The natural consequence of lead extraction procedures is the need for a subsequent device reimplantation. For this reason, when an extraction procedure is planned, the patient should be aware of the potential risks and complications related to both procedures and should be informed of potential alternatives in case of transvenous reimplantation failure. Reimplantation is not necessary in all the patients. The need for reimplantation after lead extraction cannot be always predicted before pac-ing/defibrillating system removal. In previous published studies, reimplantation rate has been reported to vary from 48% to 87% of cases [1-3] in our experience, according with other centers, reimplantation of a new device is usually not required in about 20% of patients [4, 5]. However, in all patients undergoing lead extraction, especially in case of previous infection, the ongoing need of a cardiac device should be reassessed [6]. 

Pacemaker and defibrillator systems consist of two implanted and one external component the generator, cardiac leads, and programmer, respectively (Morley-Davies and Cobbe, 1997). Although the clinical functions of pacemakers and defibrillators differ, the desired component characteristics are similar and include low complication rates coupled with small size, durabiliiy, and longevity. 

Mortis, M. M., KenKnight, B. H., Narren, J. A., and Lang, D. J., A preview of implantable cardioverter defibrillator systems in the next millenniom An integrative cardiac rhythm management approach, Am. J. Cardiol., 1999 83(5B) 48D-54D. 

Upgrading Techniques for Dual-Chambered Pacing and Defibrillator Systems... 

Kleine P, Gronefeld G, Dogan S et al. Robotically enhanced placement of left ventricular epicardial electrodes during implantation of a biventricular implantable cardioverter defibrillator system. PACE 2002 25 989-991. 

Berul Cl, Callans DJ, Schwartzman DS, Preminger MW, Gottlieb CD, Marchhnski FE. Comparison of initial detection and redetection of ventricular fibrillation in a transvenous defibrillator system with automatic gain control. J Am Coll Cardiol 1995 25 431-6. 

Bardy GH, Allen MD, Mehra R, Johnson G. An effective and adaptable transvenous defibrillation system using the coronary sinus in humans. J Am Coll Cardiol 1990 16 887-95. 

Glikson M, Trusty JM, Grice SK, Hayes DL, Hammill SC, Stanton MS. A stepwise testing protocol for modem cardioverter defibrillator systems to prevent pacemaker-implantable cardioverter defibrillator interactions. Am J Cardiol 1999 83 360-366. 

Fig. 18.36 Posteroanterior chest radiograph obtained after the prior device was upgraded to a cardiac resynchronization therapy defibrillator system. During the course of the upgrade, the central venous circulation was perforated, and when dye was injected to determine the position of the sheath, the contrast material was seen in the mediastinum.

Rosenthal ME, and Paskman C. Noise detection during bradycardia pacing with a hybrid nonthoracotomy implantable cardioverter defibrillator system incidence and clinical significance. Pacing Clin Electrophysiol 1998 21 1380-1386. 

A response to emergencies will also involve the consideration and maintenance of physical systems. This could include adequate coverage and operation of a sprinkler system and fire extinguishers. It could also include the location, maintenance, and operation of automated external defibrillators. Systems and equipment need to be identified, and a process must be put in place to ensure that they remain operational. 

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