Journal of Arrhythmia (Aug 2013)

Factors involved in correct analysis of intracardiac electrograms captured by Medtronic Inc. pacemakers during tachycardias

  • Masaru Takagaki, ME,
  • Shigeru Ikeguchi, MD,
  • Tomoyuki Yamada, MD,
  • Kazuhiko Katsuyama, MD,
  • Yuzo Takeuchi, MD,
  • Shinsaku Takeda, MD,
  • Yoshitaka Kawata, MD,
  • Takeshi Harita, MD,
  • Akio Morii, ME,
  • Hiroaki Nanba, ME,
  • Shinichi Hasegawa, ME,
  • Shinichiro Sukenari, ME,
  • Hiroshi Terada, ME

DOI
https://doi.org/10.1016/j.joa.2012.09.004
Journal volume & issue
Vol. 29, no. 4
pp. 204 – 210

Abstract

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Background: To thoroughly investigate the diagnostic information obtained by pacemakers, it is important that the stored intracardiac electrograms (EGMs) are analyzed. However, in Medtronic pacemakers, only a single intracardiac recording channel is available and thus EGM channel selection is critical. Methods: The study population comprised 150 patients who underwent implantation of Medtronic's dual chamber pacemakers with a single intracardiac EGM memory channel. We first set the electrogram channel to “summed,” and the automatic EGM diagnosis during the tachycardia was compared with the manual analysis findings. When the results were not identical for the 2 methods, the atrial EGM (AEGM) and ventricular EGM channels were sequentially selected and the results of each EGM selection were compared to conclude which channel was more valuable for diagnosis of high-rate episodes. The post-ventricular atrial blanking (PVAB) period was adjusted to the shortest interval with a relevant margin to avoid any far-field R wave over-sensing. Results: A total of 130 patients were eventually enrolled. High-rate episodes were observed in 115/130 patients (88%). The results of the automated tachycardia diagnosis obtained using the “summed” EGM differed from those obtained manually in 43/115 patients (37%). Changing the intracardiac EGM channel from “summed” to “AEGM” enabled a much better manual diagnosis with intracardiac EGMs because of improved atrial potential sensing, clearer manifestation of atrial electrograms within the PVAB, and more prominent atrial electrograms fused with the ventricular potentials. The ventricular EGM channel was not as useful as the AEGM channel for tachycardia diagnosis. Conclusions: In Medtronic pacemakers with single intracardiac EGM channel recording capability, AEGM is the most useful of the 3 EGM channel settings; PVAB should also be set to a much shorter value to achieve a more accurate automatic diagnosis.

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