Europace Advance Access originally published online on January 11, 2008
Europace 2008 10(2):138-146; doi:10.1093/europace/eum277
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PACING
Atrial lead location at the Bachmann's bundle region results in a low incidence of far field R-wave sensing
browska-Kugacka1
ski2
Zago
don3
1 Department of Cardiology and Electrotherapy, Medical University of Gdask, ul. D
binki 7, 80-211 Gdask, Poland;
2 Department of Cardiology, Medical University of Lublin, Poland;
3 Department of Hygiene and Epidemiology, Medical University of Gdask, Poland
Aims: The aim of the study was to investigate far field R-wave sensing (FFRS) rate and characteristics at different right atrial (RA) positions in patients treated with multisite atrial pacing, with the RA lead implanted at the Bachmann's bundle (BB) area in 69 patients, in comparison to RA appendage (RAA) in 70 patients.
Methods and results: All measurements were done during sinus rhythm in supine patients, with unipolar (UP) and bipolar (BP) sensing configuration. The presence, amplitude threshold (FFRS trsh) and FFRS timing were determined. Sensing safety margin was defined as the ratio of sensed P-wave vs. FFRS trsh, for both the minimal (Pmin) and the mean (Pmean) P-wave amplitude. At both atrial locations BP sensing was superior to UP in FFRS rejection (P < 0.0001). At 0.5 mV sensitivity level (BP) FFRS occurred in 1% of patients at the BB site vs. 11% at the RAA (P = 0.01). FFRS trsh (BP) was 0.2 ± 0.1 mV at the BB vs. 0.4 ± 0.3 mV in the RAA position (P < 0.0001). Sensing safety margin, when determined for the Pmin amplitude was 
5 in 99% of patients from the BB group, in comparison to 66% of RAA patients (P < 0.0001), in whom it was <2 in 13%. Even with the use of BP leads equipped with a 10 mm tip-to-ring spacing FFRS incidence was lower at the BB site (P < 0.01), FFRS trsh was lower (P < 0.001), and sensing safety margin was higher vs. RAA (P = 0.002).
Conclusion: Bachmann's bundle area features optimal conditions for signal sensing, and such atrial lead positioning may offer advantages to prevent oversensing of R-wave, thus improving functioning of standard dual chamber pacemakers, ICDs and CRT-Ds.
Key Words: Oversensing, Far field R-wave sensing, Bachmann's bundle, Atrial fibrillation, Atrial blanking time, Atrial lead
* Corresponding author. Tel: +48 58 349 39 10; fax: +48 58 349 39 20. E-mail address: elew{at}amg.gda.pl
Manuscript submitted 14 August 2007. Accepted after revision 22 November 2007.