Introduction: Optimizing atrial automatic capture verification based on atrial-evoked response (AER) detection requires maximizing the signal artifact ratio (SAR), that is, AER to stimulation artifact (ART). This study evaluated the effect of bipolar atrial lead position on sensed AER, ART, and SAR.
Methods and results: A custom-made external research system (INSIGNIA(AC), Boston Scientific Corp. St Paul, MN, USA) was used to perform an automatic voltage step-down atrial pacing protocol at three different right atrial lead positions (A-appendage, L-lateral wall, and S-septal wall) in each studied patient. The atrial pacing and the AER sensing configurations were independent. The pacing was unipolar in an A(tip)-Can configuration while sensing was in A(ring)-I(ndiff). Data from 16 patients (mean age 71.1 +/- 9.6 years) and six-lead models from five different manufacturers were analyzed. Study results show that with all lead types, the atrial lead placement had no significant effect on AER(min), ART(max), and SAR(min) and only one patient had an SAR that was not sufficient to support successful automatic capture verification at all tested atrial pacing sites.
Conclusion: The atrial pacing site has minimal effect on AER sensing when using an independent pace/sense configuration. The leads placed at all tested sites were found to have the parameters sufficient to support the atrial automatic capture verification in all but one patient.