title: Hemodynamic Surveillance of Ventricular Pacing Effectiveness with the Transvalvular Impedance Sensor.
abstract: 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.
authors.affiliation: Arrhythmology OU, Ferrarotto Hospital, University of Catania, Catania, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Calvi
authors.affiliation: Arrhythmology OU, Cardiology Department, Fogliani Hospital, Milazzo, Messina, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pizzimenti
authors.affiliation: Arrhythmology OU, Cardiology Department, Cannizzaro Hospital, Catania, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Lisi
authors.affiliation: Cardiology Department, Garibaldi-Centro Hospital, Catania, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Doria
authors.affiliation: Arrhythmology OU, Cardiology Department, Fogliani Hospital, Milazzo, Messina, Italy.
authors.forename: Ludovico
authors.initials: L
authors.lastname: Vasquez
authors.affiliation: Arrhythmology OU, Cardiology Department, Cannizzaro Hospital, Catania, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Lisi
authors.affiliation: Cardiology Department, Garibaldi-Centro Hospital, Catania, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Felis
authors.affiliation: Arrhythmology OU, Ferrarotto Hospital, University of Catania, Catania, Italy.
authors.forename: Donatella
authors.initials: D
authors.lastname: Tempio
authors.affiliation: Arrhythmology OU, Ferrarotto Hospital, University of Catania, Catania, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Virgilio
authors.affiliation: Clinical Research Unit, Medico Spa, Rubano, Padova, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Barbetta
authors.affiliation: Clinical Research Unit, Medico Spa, Rubano, Padova, Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Di Gregorio