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Reliability and Variability of Impedance Measured by Real‐Time Telemetry
Author(s) -
SCHUCHERT ANDREAS,
CAPPATO RICCARDO,
KUCK KARLHEINZ,
MEINERTZ THOMAS
Publication year - 1996
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1996.tb03326.x
Subject(s) - telemetry , medicine , electrical impedance , pulse (music) , ohm , biomedical engineering , reliability (semiconductor) , cardiology , telecommunications , electrical engineering , detector , computer science , engineering , power (physics) , physics , quantum mechanics
With the aim to detect dysfunction of pacing leads, most present‐day pacemakers measure pacing impedance by means of real‐time telemetry. The recommended setting for impedance measurement is 5.0 V for pulse amplitude and 0.5 ms for pulse duration. Availability of reliable settings would facilitate impedance measurements during follow‐up. The purpose of the present study was twofold: (1) to assess whether telemetrically measured impedance of the studied pacemaker is similar to impedance measured at implantation; and (2) to evaluate whether the pacemaker setting influences telemetrically measured impedance. Sixty‐five consecutive patients receiving VVI(R) pacemakers were studied; in all patients, impedance measured at implantation by a pacing system analyzer was compared to measurements obtained telemetrically within 1 day after implantation. In 44 other patients, impedance was determined 3 months after implantation at 60 and 120 ppm (n = 44), twice at 60 ppm (n = 42), and 12 months after implantation at 60 ppm (n = 34). For each measurement, pulse amplitude was programmed to 0.8, 1.6, 2.5, 5.0, and 8.0 V, and pulse duration to 0.05, 0.25, 0.50, and 1.00 ms. Impedance at implantation (606 ± 113 ohms) did not differ from the data obtained with telemetry (629 ± 113 ohms; P = NS). Different pacing rates, repeat measurements, and follow‐up time failed to show any influence on impedance. Measurement tolerance was < 10% for 15 of 19 studied settings other than 5.0 V and 0.5 ms. Conclusion: The studied pacemakers provide reliable data for telemetrically measured impedance. Telemetrical impedance does not necessarily have to be measured at 5.0 Vand 0.5 ms. These findings should be considered for measurement and interpretation of real‐time telemetry impedance during follow‐up.