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Hemodynamic Surveillance of Ventricular Pacing Effectiveness with the Transvalvular Impedance Sensor.

Calvi V, Pizzimenti G, Lisi M, Doria G, Vasquez L, Lisi F, Felis S, Tempio D, Virgilio A, Barbetta A, Di Gregorio F - Adv Med (2014)

Bottom Line: When the energy scan resulted in capture loss, the TVI system must detect the failure and increase the output voltage.The procedure was never interrupted by the physician, as the automatic energy regulation ensured full patient's safety.The median prevalence of false alarms was 0.336%.

View Article: PubMed Central - PubMed

Affiliation: Arrhythmology OU, Ferrarotto Hospital, University of Catania, Catania, Italy.

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.

No MeSH data available.


Real-time telemetry from the implanted pacemaker. Event markers (upper tracing; short bar = atrial sensing; long bar = ventricular pacing) and transvalvular impedance (TVI; middle tracing; recording in ventricular tip configuration) are matched with the surface ECG (lead II; lower tracing). The horizontal grey bars represent the TVI blanking period following the ventricular spike emission. Atrium-driven (a) and VVI stimulation (b) are compared in the same patient.
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fig1: Real-time telemetry from the implanted pacemaker. Event markers (upper tracing; short bar = atrial sensing; long bar = ventricular pacing) and transvalvular impedance (TVI; middle tracing; recording in ventricular tip configuration) are matched with the surface ECG (lead II; lower tracing). The horizontal grey bars represent the TVI blanking period following the ventricular spike emission. Atrium-driven (a) and VVI stimulation (b) are compared in the same patient.

Mentions: TVI was derived with the tip ventricular electrode in 52% of the patients and with the ring in the remaining 48%. When the atrial ring-ventricular tip configuration was chosen, TVIpk-pk was higher with AV sequential than VVI pacing (45.0 ± 22.3 and 39.9 ± 22.9 Ohm, resp.; P < 0.005). The individual ratio of TVIpk-pk in VVI and VDD averaged 0.87 ± 0.22 in this subgroup of patients. When TVI was derived in atrial ring-ventricular ring configuration, TVIpk-pk was remarkably lower and no significant difference related to the pacing mode was noticed (17.5 ± 8.4 and 16.4 ± 7.0 Ohm in AV sequential and VVI pacing, resp.). In most cases featuring a lower TVIpk-pk with VVI pacing, the difference resulted from a higher beat-to-beat variability compared with sequential activation (the coefficient of variation was 0.18 ± 0.11 and 0.13 ± 0.08, resp.; P < 0.05), associated with the anticipation of TVI rise. Due to the earlier signal onset, the actual minimum TVI could occur in the blanking period following the ventricular spike and thus could be skipped by the measurement of TVI excursion performed by the pacemaker. A comparison of TVI signals recorded in the same patient in VDD and VVI pacing is shown in Figure 1. In this representative case, TVI was derived by the ventricular tip electrode. In VDD, the waveform featured a gradual increase taking place mainly after the end of the blanking period, and the measured TVIpk-pk averaged 45.8 ± 3.3 Ohm with a variation coefficient equal to 0.07. In VVI, in contrast, the TVI rise started within the blanking, so that the measured TVIpk-pk was reduced to 26.8 ± 9.7 Ohm, with a variation coefficient of 0.36.


Hemodynamic Surveillance of Ventricular Pacing Effectiveness with the Transvalvular Impedance Sensor.

Calvi V, Pizzimenti G, Lisi M, Doria G, Vasquez L, Lisi F, Felis S, Tempio D, Virgilio A, Barbetta A, Di Gregorio F - Adv Med (2014)

Real-time telemetry from the implanted pacemaker. Event markers (upper tracing; short bar = atrial sensing; long bar = ventricular pacing) and transvalvular impedance (TVI; middle tracing; recording in ventricular tip configuration) are matched with the surface ECG (lead II; lower tracing). The horizontal grey bars represent the TVI blanking period following the ventricular spike emission. Atrium-driven (a) and VVI stimulation (b) are compared in the same patient.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4590946&req=5

fig1: Real-time telemetry from the implanted pacemaker. Event markers (upper tracing; short bar = atrial sensing; long bar = ventricular pacing) and transvalvular impedance (TVI; middle tracing; recording in ventricular tip configuration) are matched with the surface ECG (lead II; lower tracing). The horizontal grey bars represent the TVI blanking period following the ventricular spike emission. Atrium-driven (a) and VVI stimulation (b) are compared in the same patient.
Mentions: TVI was derived with the tip ventricular electrode in 52% of the patients and with the ring in the remaining 48%. When the atrial ring-ventricular tip configuration was chosen, TVIpk-pk was higher with AV sequential than VVI pacing (45.0 ± 22.3 and 39.9 ± 22.9 Ohm, resp.; P < 0.005). The individual ratio of TVIpk-pk in VVI and VDD averaged 0.87 ± 0.22 in this subgroup of patients. When TVI was derived in atrial ring-ventricular ring configuration, TVIpk-pk was remarkably lower and no significant difference related to the pacing mode was noticed (17.5 ± 8.4 and 16.4 ± 7.0 Ohm in AV sequential and VVI pacing, resp.). In most cases featuring a lower TVIpk-pk with VVI pacing, the difference resulted from a higher beat-to-beat variability compared with sequential activation (the coefficient of variation was 0.18 ± 0.11 and 0.13 ± 0.08, resp.; P < 0.05), associated with the anticipation of TVI rise. Due to the earlier signal onset, the actual minimum TVI could occur in the blanking period following the ventricular spike and thus could be skipped by the measurement of TVI excursion performed by the pacemaker. A comparison of TVI signals recorded in the same patient in VDD and VVI pacing is shown in Figure 1. In this representative case, TVI was derived by the ventricular tip electrode. In VDD, the waveform featured a gradual increase taking place mainly after the end of the blanking period, and the measured TVIpk-pk averaged 45.8 ± 3.3 Ohm with a variation coefficient equal to 0.07. In VVI, in contrast, the TVI rise started within the blanking, so that the measured TVIpk-pk was reduced to 26.8 ± 9.7 Ohm, with a variation coefficient of 0.36.

Bottom Line: When the energy scan resulted in capture loss, the TVI system must detect the failure and increase the output voltage.The procedure was never interrupted by the physician, as the automatic energy regulation ensured full patient's safety.The median prevalence of false alarms was 0.336%.

View Article: PubMed Central - PubMed

Affiliation: Arrhythmology OU, Ferrarotto Hospital, University of Catania, Catania, Italy.

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.

No MeSH data available.