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Can current minute ventilation rate adaptive pacemakers provide appropriate chronotropic response in pediatric
Marco E Cabrera1, Gerry Portzline, Susan Aach
1mec6@po.cwru.edu
Insights
Minute ventilation (MV) sensors in pacemakers show promise for pediatric use. Simulations indicate MV accurately reflects children's heart rate response during exercise, supporting clinical validation for pediatric pacemaker patients.
Area of Science:
- Biomedical Engineering
- Pediatric Cardiology
Background:
- Adult-designed minute ventilation (MV) sensors may not adequately capture pediatric exercise responses.
- High respiratory rates in children exceed the sensing capabilities of current MV rate-responsive pacemakers.
Purpose of the Study:
- To evaluate the MV sensor rate response of the Medtronic Kappa 400 pacemaker in children.
- To assess the suitability of MV as a parameter for chronotropic control in pediatric pacemaker patients.
Main Methods:
- A computer simulation of the Medtronic Kappa 400 rate response algorithm was used.
- Exercise data from 38 healthy children (ages 6-14) undergoing treadmill tests were analyzed.
- Respiratory rates and tidal volumes were input into the algorithm to calculate sensor-driven heart rates.
Main Results:
- Simulated sensor-driven rates closely matched intrinsic heart rates during exercise across different body surface area groups.
- High correlations were observed between sensor-driven rates and heart rate responses, as well as minute ventilation.
- No significant differences were found between sensor-driven and intrinsic heart rates using the Wilkoff model.
Conclusions:
- Minute ventilation is a suitable physiological parameter for controlling heart rate in children.
- The findings support the clinical validation of MV sensor technology in pediatric pacemaker recipients.
Abstract:
Since children have different activity patterns and exercise responses, uncertainty exists as to whether minute ventilation (MV) sensors designed for adults provide adequate chronotropic response in pediatrics. In particular, high respiratory rates (RR > 48 breaths/min), which are characteristic of the ventilatory response to exercise in children, cannot be sensed by MV rate responsive pacemakers. The purpose of this study was to evaluate the MV sensor rate response of the Medtronic Kappa 400 using exercise data from healthy children in a computer simulation of its rate response algorithm. Thirty-eight healthy children, ages 6-14, underwent a treadmill maximal exercise test. Subjects were divided based on body surface area (BSA) and MV rate response parameters were selected. Respiratory rates and tidal volumes were entered into the Kappa 400 rate response algorithm to calculate sensor-driven rates. Intrinsic heart rate (HR), oxygen uptake, and sensor-driven rates were normalized to HR reserve (HRR), metabolic reserve (MR), and sensor-driven reserve to compare across groups. Linear regression analysis among sensor-driven rate reserve, HRR, and MR was performed as described by Wilkoff. The mean slopes (+/- SD) of the relationships between the sensor-driven rate reserve and HRR were 1.06 +/- 0.34, 1.07 +/- 0.28, and 1.01 +/- 0.19 for children with BSA < 1.10 m2, 1.10 < BSA < 1.40 m2, and BSA > 1.40 m2, respectively. High correlations were found between sensor-drive rates and HR responses and between sensor-drive rates and MV throughout exercise. No significant differences were noted between sensor-drive rates and HR using the Wilkoff model. From this study the authors conclude that: (1) MV is a good physiological parameter to control heart rate and (2) simulated sensor-driven rates closely match intrinsic HRs during exercise in healthy children, which supports the appropriateness of clinical validation in pediatric pacemaker patients.