Sensing performance, safety, and patient acceptability of long-dipole cardiac monitor: An innovative axillary insertion

Background: The recommended location for implantable cardiac monitor (ICM) insertion is the left pectoral region. We tested whether an innovative left axillary implantation approach could be applicable for a new ICM, characterized by a long sensing dipole. Methods: We considered a series of 55 patients consecutively implanted with a long-dipole ICM (BioMonitor 2); the first 30 subjects underwent prepectoral location insertion, while the subsequent 25 received the ICM in the axillary region. Sensing performances collected at 1-month follow-up were compared between the two groups. During the visit, each patient was also asked to fill in a brief questionnaire to assess patient acceptability of the device. Results: All patients had a successful insertion of ICM. Mean R-wave amplitude was 0.87 ± 0.44 mV in the prepectoral group and 1.00 ± 0.45 mV in the axillary one, without any significant difference. The percentage of patients with visible P wave was also comparable between the two approaches (65.5% vs 68.2%, P = 0.84). None of the patients reported device-related issues or discomfort, and ICM was generally well accepted and tolerated by all the involved patients. Conclusion: Axillary insertion may represent a valid alternative to the standard one for long-dipole ICM technology providing not only patient acceptability but also high-quality sensing performances.