Opportunities and challenges surrounding the use of implantable haemodynamic monitor in paediatric Fontan patients living in high-altitude, rural settings

Implantable haemodynamic monitors allow remote monitoring of Fontan circulation. We report unique opportunities and challenges related to device use in rural, high-altitude regions. Assess the performance of implantable haemodynamic monitor in Fontan circulation and identify potential sources of measurement discrepancy defined as non-physiological, negative, or significantly lower reading than baseline. We performed a retrospective review of patients who underwent implantable haemodynamic monitor implantation from September 2021 to April 2024 (n = 17) at our centre (∼1,000 feet above sea level; ASL) and identified those with sensor discrepancies. During a mean follow-up duration of 26 months (range 13-44 months), there were no procedure-related complications, thromboembolism, or device displacement. Ten patients lived in rural, higher-altitude regions (average altitude 5100 feet above sea level, average distance from centre ∼160 miles, range = 100-400 miles). Challenges in remote monitoring included unreliable home-internet connection, non-compliance, and difficulty performing device recalibration at patient's home altitude. Sensor discrepancies were noted in 7 patients (41%), of whom 6 (86%) lived remotely. Manual review of the waveforms identified sources of discrepancy, including misinterpretation of the non-pulsatile pressure waveform (n = 3), offset due to change in hospital-interrogation unit (n = 4), and sensor drift (n = 1). Altitude change did not directly affect sensor performance. We were able to apply corrective interventions in 4/7 sensors, including Fontan-specific settings (overriding pulsatility), and back-end recalibration, which were effective in improving device accuracy. Implantable haemodynamic monitors are a promising tool for monitoring Fontan circulation but may require modified settings and careful attention to potential interpretation errors. Home monitoring remains challenging for rural, high-altitude residents with limited resources.