Epicardial pacing

A woman with congenital heart disease and atrial and ventricular arrhythmias managed by an implanted cardioverter defibrillator, epicardial pacing and amiodarone 400 mg daily, experienced deterioration in the control of her condition. She developed palpitations and experienced a shock from the defibrillator. Her amiodarone serum levels were 40% lower than 2 months previously, and her A-desethylamiodarone levels were undetectable. It was noted that 5 weeks earlier rifampicin 600 mg daily had been started to treat an infection of the pacing system. The amiodarone dose was doubled, but the palpitations continued. Amiodarone and A-desethy-lamiodarone levels increased after rifampicin was discontinued. Rifampicin is a potent enzyme inducer and it may have increased the metabolism and clearance of amiodarone. This case suggests that combined use of amiodarone and rifampicin should be well monitored. 

Karpawich PP, Hakimi M, Arciniegas E Improved chronic epicardial pacing in children Steroid contrihution to porous platinised electrodes. PACE 1992 15 1151-1157. 

Del Nido P, et al. Temporary epicardial pacing after open heart surgery complications and prevention. J Cardiac Surg 1989 4 99. 

Naito S, Tada H, Kaneko T, et al. Biatrial epicardial pacing prevents atrial fibrillation and confers hemodynamic benefits after coronary artery bypass surgery. Pacing Clin Electrophysiol 2005 28 S146-S149. 

Numerous epicardial active fixation devices are available but are not commonly used. The radiograph in Fig. 18.24 shows four different types of leads in one patient two epicardial leads and two endocardial leads. In this patient, previous epicardial pacing did not have long-term success. Two types of leads had been used, including a stab-in epicardial-myocardial lead and a screw-in epicardial-myocardial lead. A transvenous ventricular passive fixation lead and an active fixation atrial lead are also visible. Details of these leads are also seen on the lateral view. 

Pacing of the heart may he done transcutaneously, but this is accompanied by pain. The usual method is with two epicardial electrodes and leads out through the chest to an external pacemaker, or with an implanted pacemaker. 

Pacing leads can be subdivided into a number of groups based on the area of placement and method of stimolation. Leads can be placed either on the epicardium (external surface) of the heart or, by a transvenous route, onto the endocardium (internal surface) of the right heart atrium or ventricle. Epicardial leads are used for permanent pacing in pediatric cases, where size considerations or congmtal defects prevent transvenous placement, and in patients who have undergone tricuspid valve rqilacement (Mitrani et al., 1999). Transvenous placement of the lead is the preferred route in most patients. 

Early pacing leads were either nnipolar or bipolar. A bipolar epicardial or epimyocardial system required two leads whereas, a bipolar transvenous system could be achieved using a single lead composed of two parallel insnlation tnbes containing the anode and cathode conductors. By the late... 

Stokes KB Prelmiinary studies on a new steroid eluting epicardial electrode. PACE 1988 11 1797-1803. 

Initially, almost all pacemaker and ICD procedures were approached exclusively from the epicardial point of view. But with the development of a transvenous approach, either by cutdown or percutaneous techniques, now almost aU pacemaker and ICD procedures are approached on a transvenous or nonthoracotomy basis. Today, the epicardial approach is reserved for certain unique circumstances. Electrodes can be placed on the epicardium by a variety of techniques. This involves a subxiphoid incision, and limited thoracotomy, or direct application of electrodes on an exposed heart. Recently, mediastinoscopy and thoracoscopy have been used to apply permanent pacing and rate-sensing electrodes as well as patch electrodes. The transvenous approach can be performed by venous cutdown, percutaneous venous access, or a combination of the two. 

Fig. 4.41 Location of surgical incisions for placement of epicardial systems. The common median sternotomy is not shown. (From Belott PH, Reynolds DW. Permanent pacemaker implantation. In Ellenbogen KA, Kay N, Wilkoff BL, eds. Clinical cardiac pacing. Philadelphia WB Saunders, 1995, with permission.)...

Fig. 4.42 From left to right the first electrode is an endocardial rate sensing and pacing electrode. Endocardial high-energy spring electrode in the middle pair. Epicardial patches and pair on the extreme left epicardial rate sensing electrodes. (Courtesy of Guidant, Inc., St. Paul, MN.)...

Cardiac resynchronization therapy has clearly demonstrated hemodynamic benefit in patients with advanced CHF (124-130). Successful stimulation of the Left ventricular (LV) is critical to this new therapeutic pacing modaUty. This can be accomplished by either an epicardial or endocardial approach. The endocardial approach involves access to the LV endocardium transatrially through a patent foramen ovale or a direct tiansseptal puncture. This approach is considered potentially dangerous because of the risk of thromboembolism and stroke (131). The epicardium of the LV can be accesses by direct placement... 

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