Cardiac resynchronization therapy implantation

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... 

Bristow MR, Saxon LA, Boehmer J, et al. Cardiac-resynchronization therapy with or without an implantable defibrillator in advanced chronic heart failure, [see comment]. N. Engl. J. Med. 2004 350 2140-50. 

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 1.5 Summary of evidence supporting defibrillator implantation as stratified by ejection fraction and heart failure class in patients with ischemic cardiomyopathy (A) and nonischemic cardiomyopathy (B). For details of COMPANION trial, see Chapter 5. (CRT, cardiac resynchronization therapy EPS, electrophysiology study NYHA,New York Heart Association.)... 

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. 

MADIT-CRT Automatic Defibrillator Implantation With Cardiac Resynchronization Therapy, ClinicalTrials.gov, http // www.clinicaltrials.gov/ct2/show/NCT00180271, accessed January 22,2008. 

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. 

The indication for the extraction can explain different reimplantation settings. Generally, two different scenarios can be described patients with a cardiovascular implantable electronic device (CIED) infection and patients with a malfunctioning lead. Moreover, in the era of cardiac resynchronization therapy (CRT), a specific skill in biventricular device reimplantation is required in large-volume centers and will be described separately. 

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. 

Carbon monofluoride (CFx) is one such fluoride compound that today is used as a positive electrode material in Li batteries for a number of different applications. For example, they are used in certain types of heart failure devices - implantable cardiac resynchronization therapy pacemakers (CRT-P). CRT-P devices can pace the right atrium and right ventricle, but they are also capable of pacing the left ventricle. Pacing three chambers requires more power than a cell can deliver, so a different battery type is needed. Li/CFx cells were developed in response to the increased power required by CRT-P devices. Vagal nerve stimulator devices also use a Li/CFx cells. 

Fig. 4.71 Heart rotated into the RAO projection with the right atrial cavity exposed demonstrating the superfiscial and deep anatomy of the right heart in relationship to the coronary sinus and its branch tributaries, (from Belott PH Implantation Techniques for Cardiac resynchronization Therapy Barold SS, Mugica J Fifth Decade of Cardiac...

F. 4.78 Puffs of contrast through the guiding catheter defining the CS os and lower RA anatomy. Image courtesy of Imran Nazi MD (IiDm Belott PH Implantation Techniques for Cardiac resynchronization Therapy Barold SS, Mugica J Fifth D ade of Cardiac Pacing. Armonk NY Futura. 2004 Page 7)... 

Bax JJ, Abraham T, Barold SS, Breithardt OA, Fung JW, Garrigue S, Gorcsan J, 3rd, Hayes DL, Kass DA, Knuuti J, Leclercq C, Linde C, Mark DB, Monaghan Ml, Nihoyannopoulos P, Schahj Ml, SteUbrink C, Yu CM. Cardiac resynchronization therapy Part 1-issues before device implantation. J Am CoU Cardiol 2005 46 2153-67. 

Moss AJ, Brown MW, Cannom DS, Daubert JP, Estes M, Poster E, Greenberg HM, Hall WJ, Higgins SL, Klein H, Pfeffer M, Wilber D, Zareba W. Multicenter automatic defibrillator implantation trial-cardiac resynchronization therapy (MADIT-CRT) design and clinical protocol. Ann Noninvasive Electtocardiol 2005 10 34-43. 

Management of a Biventricular Device. It has been estimated that up to 38% of patients with moderate to severe congestive heart failure due to left ventricular systolic dysfunction have intraventricular conduction delays with wide QRS complexes and ventricular dyssynchrony (79). Cardiac resynchronization therapy using a biventricular pacemaker is now a Class I indication therapy for systolic heart failure in patients with a QRS complex > 120 ms and left ventricular ejection fraction < 35% (80). Although cardiac resynchronization therapy decreases heart failure hospitalizations (81,82), as the overall number of patients with biventricular pacemakers and ICDs increase, more critical care patients will present with implanted biventricular devices, and familiarity with the management of these devices will become increasingly important. 

CRT, cardiac resynchronization therapy ICD, implantable cardioverter-defibrillator PA, posteroanterior... 

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