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Advances in Medicine
Volume 2014, Article ID 307168, 7 pages
Research Article

Hemodynamic Surveillance of Ventricular Pacing Effectiveness with the Transvalvular Impedance Sensor

1Arrhythmology OU, Ferrarotto Hospital, University of Catania, Catania, Italy
2Arrhythmology OU, Cardiology Department, Fogliani Hospital, Milazzo, Messina, Italy
3Arrhythmology OU, Cardiology Department, Cannizzaro Hospital, Catania, Italy
4Cardiology Department, Garibaldi-Centro Hospital, Catania, Italy
5Clinical Research Unit, Medico Spa, Rubano, Padova, Italy

Received 15 May 2014; Accepted 24 June 2014; Published 4 August 2014

Academic Editor: Claudia Kusmic

Copyright © 2014 Valeria Calvi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The Transvalvular Impedance (TVI) is derived between atrial and ventricular pacing electrodes. A sharp TVI increase in systole is an ejection marker, allowing the hemodynamic surveillance of ventricular stimulation effectiveness in pacemaker patients. At routine follow-up checks, the ventricular threshold test was managed by the stimulator with the supervision of a physician, who monitored the surface ECG. When the energy scan resulted in capture loss, the TVI system must detect the failure and increase the output voltage. A TVI signal suitable to this purpose was present in 85% of the tested patients. A total of 230 capture failures, induced in 115 patients in both supine and sitting upright positions, were all promptly recognized by real-time TVI analysis (100% sensitivity). The procedure was never interrupted by the physician, as the automatic energy regulation ensured full patient’s safety. The pulse energy was then set at 4 times the threshold to test the alarm specificity during daily activity (sitting, standing up, and walking). The median prevalence of false alarms was 0.336%. The study shows that TVI-based ejection assessment is a valuable approach to the verification of pacing reliability and the autoregulation of ventricular stimulation energy.