part II Permanent pacemaker implantation technique

Having addressed equipment requirements andsome of the early steps in the process of permanentpacemaker (PPM) implantation in part I of thistwo part series, this section continues with the restof the PPM implantation procedure and someaspects of post-procedural management/care.LEAD PLACEMENT TECHNIQUESBefore discussing lead placement itself, it isimportant to briefly explain the structure of apermanent pacing lead. The leads themselves arevery floppy and intrinsically have very littlestiffness. This means that as the lead is movedaround, the tip moves freely without any signifi-cant ability to steer it. To overcome this there is acentral lumen to the lead which will allow passageof a stiffer thin wire known as a ‘‘stylet’’. Thefurther the stylet is passed down the lead(potentially almost to the tip), the more of thelead body is stiffened (fig 1). These stylets may alsobe ‘‘reshaped’’ easily to allow the tip of the lead tobe further steered in a specific direction (fig 1). It isimportant to keep this stylet clean and free ofdebris, particularly blood, as this can block thecentral lumen and prevents the stylet from passingfar enough down the lead to give any usefulsupport. Also, the different lead positioning tech-niques described below are not mutually exclusive.A competent operator will be comfortable withmost of them to adapt to different situations,although they may have a preference for which onethey use first. The fixation method of the lead alsohas important implications. Lead tips may fixate‘‘passively’’ or ‘‘actively’’. Passive fixation leadshave ‘‘tines’’ at the end of the lead (fig 1) which actas an anchor to hold the lead tip in place acutely.Over a period of time (weeks to months) the tip ofthe myocardium around the lead tip will fibrose tosecure it further.An active fixation lead has a retractable screw atthe tip of the lead which is deployed when the leadis in position (fig 1). To do this the lead is firstplaced in the desired position (see below), using astylet to support the lead tip against the myocar-dium. A clip-on tool (‘‘A-frame’’) is then attachedto the distal pin of the lead and slow clockwiserotation of the distal pin transmits torque toextend the screw. This can be directly visualisedunder fluoroscopy (for some leads there is ring tipseparation, and on others the rings come together)and slight resistance may be felt when rotating thedistal pin as the myocardium is entered. Rotationof the distal tip too rapidly may build up torquewithin a lead such that the whole lead simply coilsup and the screw is not extended. To check thestability of the lead tip, the stylet is then pulledback to see that the lead stays in place before leadtesting. Specific instances where an active fixationlead may be used is when placing the rightventricular (RV) lead in the outflow tract/on thehigh septum, or in patients where the right atrial(RA) lead needs to be secured to the tissue forstability (some operators will use an active fixationRA lead in any patient who has previously hadcardiac surgery, as the RA appendage may havebeen ligated when the patient is placed oncardiopulmonary bypass). It is felt that activefixation leads are easier to extract (although whenthe lead has been in for a long period of time anylead extraction may be difficult); therefore manyoperators will electively use these in youngerpatients, knowing that over time there is amoderate chance that new leads will be neededand the old ones will need to be removed.RIGHT VENTRICULAR LEAD PLACEMENTTraditionally most RV leads have been positionedin the apex; however, there is a growing trend toplace the RV lead on the septum or in the RVoutflow tract (RVOT). The discussion of therelative merits of these different positions has beenperformed elsewhere