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278 P R I N C I P L E S A N D P R A C T I C E O F C R I T I C A L C A R E

month or so, output safety margins need to be set more right atrium and then steered back upwards to engage
generously and patients are typically sent home with the atrial appendage. Both ventricular and atrial leads
outputs set high (e.g. 3.5–5 Volts) even when thresholds are tested for performance following placement. Leads
at implantation may have been only 0.5–1 Volts. Chronic are then secured within the pacemaker pocket and the
output settings will then be established at the first post- pulse generator is attached to the leads and secured in
operative visit to the doctor in 6–8 weeks. 37 the pocket. The pocket is closed and testing is repeated to
confirm secure connections of the leads to the pacemaker.
Implantation Activities Device and lead testing is repeated on day 1, weeks 6–8
Devices are inserted under light conscious sedation and and then every 12 months to confirm operation. 38
local anaesthesia. Analgesia may also be administered at
the outset of the case, and antibiotics are commenced Pacemaker Parameters: Programming
before skin incision. An anaesthetist is usually only and Status Reports
present if judged necessary by the implanting doctor.
Knowing how a patient’s pacemaker is programmed is
Passage of leads into the heart during insertion may result crucial to interpreting pacemaker behaviour in the clini-
in endocardial contact, causing AV block or bundle cal setting. This has become increasingly important to
branch block. Therefore a femoral temporary pacing wire enable determination of whether a change in behaviour
may be inserted before progressing to placement of the is a problem or simply an automated behaviour. Device
permanent pacing leads, particularly to ensure reliable printouts are available whenever a device is interrogated
ventricular rhythm during the insertion procedure. His- or reprogrammed. The following section is a guide to
torically, ventricular leads were implanted at the apex of how to interpret device printouts to access key informa-
the right ventricle, a position easily accessed and thought tion about pacemaker programming, highlighting some
well tolerated. However recent trends have moved to of the features of the modern permanent pacemaker,
ventricular lead placement in the right ventricular outflow as well as some of the clinical and diagnostic value of
tract (RVOT), 66,73 to produce a more normal contractile the information provided. Device printouts contain an
pattern than from the apex and to prevent the ventricular enormous amount of information, but of immediate
remodelling seen in chronic RV apical pacing. 66,73 Atrial importance are the summary pages that outline all of the
lead insertion is most commonly at the right atrial operating parameters, active automated features, results
appendage, i.e. in the roof of the right atrium. The from recent tests and battery status (see Figure 11.48 for
atrial lead is passed down the superior vena cava into the an example). Important elements include:

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Accent TM DR RF 2210 (DEMO prB.E.60) FastPath TM Summary 9 Nov 2010. 17:35
Alerts Note Current Paramenters
Mode DDDR
Base Rate 60 min –1
Max Track Rate 130 min –1
Paced/Sensed AV Delay 200/150 ms
A/V Pulse Amp 2.0/1.25 V
Battery Information A/V Pulse Width 0.4/0.4 ms
Longevity: 11.1–12.2 yrs Episodes
Voltage: 3.13 V
New EGMs: 3
~ERI Most Recent: Entry Into AMS

Magnet Rate 100.0 ppm
Battery Current 9 uA Events
Text Results (Last Session: 8 Sep 2010) AP: 11% VP: 24%
100
A Automatic
Atrium Ventricle %
Time
Capture Today: 1.0 V A Today: 1.0 V A
Last Session: 1.0 V Last Session: 1.0 V
AS-VP AS-VS AP-VP AP-VS PVC
Sense Today: 4.2 mV A Today: >12.0 mV A 21% 68% 3.0% 8.0% 0%
Last Session: 4.2 mV Last Session: >12.0 mV
Lead Today: 530 Ω A Today: 530 Ω A
Impedance Last Session: 530 Ω Last Session: 530 Ω
Mode Switch
Mode Switch: 2%
AMS Episodes: 5
FIGURE 11.48 FastPath Summary from a St Jude Medical Accent™ dual chamber pacemaker (St Jude Medical Sylmar CA), highlighting basic parameters,
events, and test results recorded during pacemaker interrogation. See text for details.