Pacing leads

If the reaction was carried out in THF without any crown ether, the self-condensation reaction was observed at a much faster pace leading to the formation of a P-methoxysilyl anion (3). 

Pacemakers are among the most reliable electronic devices ever built device survival probabilities of 99.9% (excluding normal battery depletion) at 10 years are not unheard of. But despite intensive quality assurance efforts by manufacturers, the devices do remain subject to occasional failures the annual pacemaker replacement rate due to generator malfunction has been estimated at roughly one per 1000 devices implanted, a marked improvement in reliability since the early 1980s (Maisel et al. 2006 Maisel 2006). There have been multiple major advisories and recalls issued by the FDA regarding pacing leads, with more of these because of problems with the lead insulation than with the lead conductor. 

The electrode is the portion of a pacing lead that acts as a long-term interface between the lead and... 

Fig 1.5 This patient was referred to our institution for lead extraction using the internal transjugular venous approach. The fractured lead ( ) was implanted in 1975. Note that the old lead has an electrode with a broader stimulating electrode surface area. Temporary pacing lead (°)... 

The conductor of a pacing lead is basically a wire that conducts the electrical current from the pulse generator to the stimulating electrode and the sensed cardiac signals from the electrode to the sensing amplifier of the pulse generator. 

As with pacing leads, the ICD lead cathode is a platinum, iridium, and titanium combination the electrode structure depends on whether fixation mechanism is passive with tines or active with a screw. In an active-fixation lead, the platinum-iridium screw is usually electrically active, but there are also models with both electrically active collar and helix or others with electrically silent helix and active carbon cathode collar. A platinum-iridium anode lies immediately behind the cathode in a true bipolar system. All models now elute steroids to reduce chronic threshold and prevent pacing threshold rise or exit block. 

The fibrous response is related not only to actually pacing leads, but also to nonfunctional leads, indicating that it is the simple presence of the lead - with its traumatic action on the endothelium/ endocardium regardless of its elec-... 

Danilovic D, Breivik K, Hoff PI, Ohm OJ (1997) Clinical performance of steroid-eluting pacing leads with 12-mm2 electrodes. Pacing Clin Electrophysiol 20(ll) 2799-2809... 

Bongiorni MG, DI Cori A, Zucchelli G et al (2010) A modified transvenous single mechanical dilatation technique to remove a chronically implanted active-fixation coronary sinus pacing lead. Pacing Clin Electrophysiol [Epub ahead of print]... 

Fig. 2 J Transesophageal echocardiographic view of the right atrium and the right ventricle. There is an oblong mobile vegetation adherent to the pacing lead as it crosses the tricuspid valve attached to its ventricular portion. Patient had positive blood cultures for Staphylococcus lugdunensis. Both these findings are major criteria for the diagnosis of lead endocarditis...

Barakat K, Robinson NM, Spurrell RA (2000) Transvenous pacing lead-induced thrombosis a series of cases with review of the literature. Cardiology 93 142-148... 

Woscoboinik JR, Maloney JD, Helguera ME et al (1992) Pacing lead survival performance of different models. Pacing Clin Electrophysiol 15 1991-1995... 

Suga C, Hayes DL, Hyberger LK et al (2000) Is there an adverse outcome from abandoned pacing leads J Interv Card Electrophysiol 4 493 99... 

It is essential to determine whether the patient is pacemaker dependent and will require temporary pacing support during the procedure. As patients who are not pacemaker dependent prior to the procedure may become so during the procedure. In our daily practice, all patients receive a temporary pacing lead through the left femoral vein before original extraction. 

Manolis AS et al (1998) Successful percutaneous extraction of pacemaker leads with a novel (VascoExtor) pacing lead removal system. Am J Cardiol 81(7) 935-938... 

Vassilikos VP et al (1999) Percutaneous extraction of transvenous defibrillator leads using the VascoExtor pacing lead removal system. J Interv Card Electrophysiol 3(3) 247-251... 

Wilkoff BL et al (1999) Pacemaker lead extraction with the laser sheath results of the pacing lead extraction with the excimer sheath (PLEXES) trial. J Am Coll Cardiol 33(6) 1671-1676... 

Fig. 5.2 Low-profile knot performed with a nonabsorbable suture over the insulation of each conductor present in the lead (a) unipolar pacing lead (b) implantable cardioverter-defibrillator (ICD) integrated lead (c)bipolar pacing lead. The arrows show at which level the low-profile knot should be performed...

Fig 5 13 (a) The pacing lead is exposed through the introducer into the internal jugular vein and prepared as described before (with the stylet inside and a knot over each present insulation), (b) The dilatation maneuver is begun. While the right hand moves the sheath in the clockwise and counterclockwise direction in order to dilate adherences, the left hand keeps the lead in tension using the strings... 

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