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Heart, Lung and Circulation Abstracts S1152008;17S:S1–S209

274Novel Form of Pacemaker Dysfunction with IntermittentInhibition of Pacemaker Output

Hany Abed ∗, James Leitch, Malcom Barlow

The John Hunter Hospital, Newcastle, NSW, Australia

Introduction: We report a novel type of pacemaker mal-function related either to an intermittent pacemakercomponent failure or an interaction between pacemakergenerator and pacemaker leads.Methods: Details of patients and devices are shown in thetable below. Patients had received either Biotronik Actrosor Biotronik Axios devices. Medtronic leads were used inall patients.Results: The mode of failure was intermittent inappropri-ate inhibition of device output. Most patients presentedwith either pre-syncope or frank syncope at the time ofdevice malfunction. Device interrogation revealed eitherno abnormality or in one case transient elevation of leadimpedance with normal sensing. The first patient under-went generator and lead replacement. The remaining fourpatients underwent generator replacement from a differ-ent manufacturer. Subsequently, no patient had furtherproblems. The explanted devices were returned to themanufacturer for detailed analysis, but no abnormalitywas identified. Technical advice from the manufacturersuggested that this type of failure could result fromiBoCdo

nt dur

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P nths

P nths

P nths

P nths

d

275Incidence and Prognostic Impact of New Onset Atrial Fib-rillation Varies with Acute Coronary Syndrome Severity

Dennis H. Lau 1,∗, Luan T. Huynh 2, Derek P. Chew 2,Carolyn M. Astley 2, Ashish Soman 3, Glenn D. Young 1,Prashanthan Sanders 1

1 Cardiovascular Research Centre, Department of Cardiology,Royal Adelaide Hospital and the Disciplines of Medicine andPhysiology, University of Adelaide, Adelaide, SA, Australia;2 Department of Cardiology, Flinders University, Flinders Med-ical Centre, Adelaide, SA, Australia; 3 Sanofi-Aventis, Australia

Introduction: Atrial fibrillation (AF) is a predictor of pooreroutcome in acute coronary syndrome (ACS). However,whether its incidence and prognostic impact differs withthe varying ACS severity is unknown.Methods: The Acute Coronary Syndrome ProspectiveAudit Study (ACACIA, PM L 0051) is a prospectivemulti-centre registry of 3402 patients involving 39 sitesacross Australia between November 2005 and June 2007with 12-month outcome data in 3393 [755 ST elevationmyocardial infarction (STEMI), 1942 high-risk (ACS-HR)and 696 intermediate-risk (ACS-IR) non-ST elevationACS].Results: There were 149 (4.4%) new onset AF (nAF)and 387 (11.4%) with a past history of AF (phxAF). nAFwas most while phxAF was least frequent in STEMI vs.ACS-HR and ACS-IR (6.5 vs. 4.6 and 1.6% and 5.2 vs.1pan(

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d

ncompatibility between the Biotronik generator and non-iotronik leads. An alternative explanation is some formf intermittent generator component failure.onclusions: Patients with Biotronik Axios and Actrosevices should be reviewed closely for this unusual formf device malfunction.

Device V Lead A Lead Impla

atient 1, age 84 Biotronik ActrosVVIR

Medtronic 5024M – 40 mo

atient 2, age 68 Biotronik AxiosDR

Medtronic 5076 Medtronic 5076 36 mo

atient 3, age 72 Biotronik AxiosDR

Medtronic 4524M Medtronic 4524 72 mo

atient 4, age 67 Biotronik ActrosDR

Medtronic 5024M Medtronic 4524 75 mo

atient 5, age 77 Biotronik AxiosDR

Medtronic 5092 Medtronic 5594 42 mo

oi:10.1016/j.hlc.2008.05.275

ation Implant indication Symptom Pacemaker failure

Slow atrial fibrillation Pre-syncope Impedance >3200 �. Noventricular pacing

Complete heart block Syncope Intermittent completeinhibition of PPM output

Second degree AV block Syncope Complete inhibition of PPMoutput persisting for severalhours

AV node ablation Detection onroutinefollow-up

Intermittent inhibition ofatrial and ventricular output

AV node ablation Pre-syncope Intermittent inhibition ofventricular output

4.6 and 9.3% respectively; P < 0.001). Both nAF and phxAFatients were older with more heart failure at presentations compared to those without arrhythmia (CTL) (P < 0.004).AF patients were discharged on more new medications

P < 0.03) and had longer hospitalisations (P < 0.001) vs.

TL and phxAF patients. nAF but not phxAF, was asso-iated with worse overall long term composite outcomef deaths, myocardial infarction and stroke (adjusted HR.7, P = 0.004). There was a trend in higher prognosticurden of nAF in those with unstable angina vs. non-TEMI and STEMI (adjusted OR 3.9 vs. 2.0 and 1.4;< 0.03).Conclusions: nAF was more common in thoseith greater severity of ACS but its prognostic impact wasigher in the less severe ACS spectrum. Only nAF wasredictive of long-term adverse outcomes.

oi:10.1016/j.hlc.2008.05.276