Implantable cardioverter defibrillator therapy

Morgan JM. Cost-effectiveness of implantable cardioverter defibrillator therapy. J Cardiovasc Electrophysiol. Jan2002 13(l Suppl) S114- l 17. 

FIGURE 1.6 Kaplan-Meier estimates of death from any cause in patients with both ischemic and nonischemic cardiomyopathy randomized to amiodarone, placebo, or implantable cardioverter-defibrillator therapy in SCD-HeFT. (From Ref. 29, with permission.)... 

Wilkoff BL, Hess M, Young J, Abraham WT. Differences in tachyarrhythmia detection and implantable cardioverter defibrillator therapy by primary or secondary prevention indication in cardiac resynchronization therapy patients. J Cardiovasc Electrophysiol 2004 15 1002-9. 

Rinaldi CA, Simon RD, Geelen P et al (2003) A randomized prospective study of single coil versus dual coil defibrillation in patients with ventricular arrhythmias undergoing implantable cardioverter defibrillator therapy. Pacing Clin Electrophysiol 26 1684-1690... 

Germane JJ, Reynolds M, Essebag V, Josephson ME. Frequency and causes of implantable cardioverter-defibrillator therapies is device therapy proarrhythmic Am J Cardiol 2006 97 1255-61. 

Coirado, D., et al, Implantable cardioverter-defibrillator therapy for prevention of sudden death in patients with arrhythmogenic right ventricular cardiomyopathy/ dysplasia. Circulation, 2003. 108(25) p. 3084-91. 

Alter, P., et al.. Complications of implantable cardioverter defibrillator therapy in 440 consecutive patients. Pacing Chn Electrophysiol, 2005. 28(9) p. 926-32. 

Larsen GC, Manolis AS, Sonnenberg FA, et al. Cost-effectiveness of the implantable cardioverter-defibrillator effect of improved battery life and comparison with amiodarone therapy. J Am Coll Cardiol 1992 19 1323-34. 

The use of antiarrhythmic drugs in the United States is declining because of major trials that showed increased mortality with their use in several clinical situations, the realization of proarrhythmia as a significant side effect, and the advancing technology of nondrug therapies such as ablation and the implantable cardioverter-defibrillator (ICD). 

Abstract Two thirds of the nearly half a million deaths per year in the United States due to sudden cardiac death (SCD) is attributed to coronary artery disease (CAD) and most commonly results from untreated ventricular tachyarrhythmias. Patients with ischemic cardiomyopathy and left ventricular dysfunction are at highest risk for SCD, but this still defines only a small subset of patients who will suffer SCD. Multiple lines of evidence now support the superiority of implantable cardioverter defibrillator (ICD) therapy over antiarrhythmic therapy for both primary and secondary prevention of SCD in advanced ischemic heart disease. Optimization of ICD therapy in advanced ischemic cardiomyopathy includes preventing right ventricular pacing as well as the use of highly effective anti-tachycardia pacing to reduce the number of shocks. While expensive, ICD therapy has been shown to compare favorably to the accepted standard of hemodialysis in cost effectiveness analyses. 

Implantable cardioverter defibrillator implantation is expensive, with an estimated cost of 30,000- 50,000 per implant, not including the cost of follow-up. However, economic analysis of ICD studies has shown that ICD implantation compares favorably with such commonly accepted therapies as dialysis for end-stage renal failure [47]. It is estimated that the cost effectiveness ratio for ICDs is 27,000 per life year saved, comparable to those for other well-... 

However, the long-term effects of cardiac resynchronization therapy (CRT) on morbidity and mortality were not known. Two clinical trials have established the morbidity and mortality effects of CRT. The COMPANION trial was a three armed trial, testing optimal medical therapy (OPT) against OPT plus CRT by a pacemaker or a OPT plus CRT by an implantable cardioverter-defibrillator (CRT-D) [118]. In this study, patients were enrolled prior to... 

As left ventricular dysfunction is a major predictor of sudden arrhythmic death, cardiac death and total mortality, it can be stated that in general sudden cardiac death prevention is achievable with the combination of an implantable cardioverter defibrillator (ICD) and medical therapy. 

The first implantable cardioverter-defibrillator (ICD) was placed in 1982. Since that time, their use has expanded exponentially. Several large clinical trials have demonstrated the superiority of ICDs compared with pharmacological therapy for the secondary prevention of arrhythmic death and possibly as primary therapy for patients at risk for ventricular arrhythmias. 

Low doses (100-200 mg/d) of amiodarone are effective in maintaining normal sinus rhythm in patients with atrial fibrillation. The drug is effective in the prevention of recurrent ventricular tachycardia. It is not associated with an increase in mortality in patients with coronary artery disease or heart failure. In many centers, the implanted cardioverter-defibrillator (ICD) has succeeded drug therapy as the primary treatment modality for ventricular tachycardia, but amiodarone may be used for ventricular tachycardia as adjuvant therapy to decrease the frequency of uncomfortable cardioverter-defibrillator discharges. The drug increases the pacing and defibrillation threshold and these devices require retesting after a maintenance dose has been achieved. 

Brennan TD, Haas GJ. The role of prophylactic implantable cardioverter defibrillators in heart failure recent trials usher in a new era of device therapy. Curr Heart Fail Rep. 2005 2 40-45. 

In 154 patients with implantable cardioverter-defibrillators randomly assigned to dofetilide or placebo, there were pause-dependent runs of polymorphic ventricular tachycardia in 15 of the 87 patients who received dofetilide and in only five of the 87 who received placebo (57). There were five early events (at less than 3 days of therapy), all torsade de pointes in patients taking dofetilide. There were 15 late events, 10 with dofetilide and five with placebo. The median time to a late event was 22 (range 6-107) days for dofetilide and 99 (34—207) days for placebo. 

Recent studies demonstrate that cardiac resynchronization therapy (CRT) offers a promising approach to selected patients with chronic heart failure. Delayed electrical activation of the left ventricle, characterized on the ECG by a QRS duration that exceeds 120 ms, occurs in approximately one-third of patients with moderate to severe systolic heart failure. Since the left and right ventricles normally activate simultaneously, this delay results in asynchronous contraction of the left and right ventricles, which contributes to the hemodynamic abnormalities of this disorder. Implantation of a speciahzed biventricular pacemaker to restore synchronous activation of the ventricles can improve ventricular contraction and hemodynamics. Recent trials show improvements in exercise capacity, NYHA classification, quality of life, hemodynamic function, and hospitalizations. A device that combined CRT with an implantable cardioverter-defibrillator (ICD) improved survival in addition to functional status. CRT is currently indicated only in NYHA class ni-IV patients receiving optimal medical therapy (ACE inhibitors, diuretics, -blockers, and digoxin) and... 

FIGURE 17-16. Example of an approach to the management of survivors of cardiac arrest (resuscitated VT/VF). Reversible causes of cardiac arrest (e.g., electrolyte abnormalities, acute phase of Ml) should be treated with specific therapy. AADs = antiarrhythmic drugs BBs = /i-blockers EPS = invasive electrophysio-logic studies ICD = implantable cardioverter-defibrillator VT/VF = ventricular tachycardia/ventricular fibrillation Ml = myocardial infarction. 

Boriani G, Muller CP, Seidl KH, et al. Randomized comparison of simultaneous biventricular stimulation versus optimized interventricular delay in cardiac resynchronization therapy. The Resynchronization for the HemodYnamic Treatment for Heart Failure Management II implantable cardioverter defibrillator (RHYTHM IIICD) study. Am Heart J 2006 151 1050-8. 

There are three implantable devices used today to treat cardiac arrhythmias - the pacemaker, the implantable cardioverter defibrillator (ICD), and the cardiac resynchronization therapy (CRT) devices for heart failure patients. 

The implantable cardioverter defibrillator (ICD) is a cardiac pacemaker. It can be used to pace one or both chambers on the right side of the heart It has an additional feature, though. ICDs can also impart powerful shocks to the heart if it is beating too fast (tachycardia) or goes into ventricular fibrillation. Either condition means that blood cannot be pumped very efficiently, if at all. A number of major clinical studies were done that identified various categories of heart patients who could benefit from the therapies delivered by devices like the ICD. 

Giudici MC, Barold SS, Paul DL. Pacemaker and implantable cardioverter defibrillator implantation without reversal of warfarin therapy. PACE 27 358, 2004. 

Sweeney MO, Wathen MS, Volosin K, Abdalla I, DeGroot PJ, Ottemess MF, Stark AJ. Appropriate and inappropriate ventricular therapies, quality of life, and mortality among primary and secondary prevention implantable cardioverter defibrillator patients results from the Pacing Fast VT REduces Shock ThErapies (PainFREE Rx II) trial. Circulation 2005 111 2898-905. 

Wathen MS, DeGroot PJ, Sweeney MO, Stark AJ, Ottemess MF, Adkisson WO, Canby RC, Khalighi K, Machado C, Rubenstein DS, Volosin KJ. Prospective randomized multicenter trial of empirical antitachycardia pacing versus shocks for spontaneous rapid ventricular tachycardia in patients with implantable cardioverter-defibrillators Pacing Fast Ventricular Tachycardia Reduces Shock Therapies (PainFREE Rx It) trial results. Circulation 2004 110 2591-6. 

Niehaus M, Neuzner J, Vogt J, Korte T, Tebbenjohanns J. Adjustment of maximum automatic sensitivity (automatic gain control) reduces inappropriate therapies in patients with implantable cardioverter defibrillators. Pacing Clin Electrophysiol 2002 25 151-5. 

Dorian P, Philippon F, Thibault B, Kimber S, Stems L, Greene M, Newman D, Gelaznikas R, Barr A. Randomized controlled study of detection enhancements versus rate-only detection to prevent inappropriate therapy in a dual-chamber implantable cardioverter-defibrillator. Heart Rhythm 2004 1 540-7. 

Theuns DA, Klootwijk AP, Goedhart DM, Jordaens LJ. Prevention of inappropriate therapy in implantable cardioverter-defibrillators results of a prospective. 

Chung MK, Streem SB, Ching E, Grooms M, Mowrey KA, Wilkoff B. Effects of extracorporeal shock wave lithotripsy on tiered therapy implantable cardioverter defibrillators. Pacing Clin Electrophysiol 1999 22 738-742. 

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