Impact of device length on electrogram sensing in miniaturized insertable cardiac monitors.

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Devices

Background:

• Limited data exists on electrogram (ECG) sensing capabilities of current miniaturized insertable cardiac monitors (ICMs).
• Understanding sensing performance is crucial for effective remote patient monitoring and diagnosis.

Purpose of the Study:

• To compare the electrogram sensing capabilities of two ICMs with different lead lengths: Biotronik Biomonitor III (BM-III, ~70 mm) and Medtronic Reveal LINQ (~40 mm).
• To evaluate the impact of body mass index (BMI) and gender on P-wave amplitude and visibility.

Main Methods:

• A comparative analysis of de-identified remote monitoring transmissions from 40 BM-III patients and 80 matched Reveal LINQ patients.
• Independent digital measurement of P-wave and R-wave amplitudes from calibrated ICM electrograms by three investigators.
• Logistic regression analysis to assess the association of ICM type, BMI, and gender with P-wave amplitude.

Main Results:

• BM-III demonstrated significantly larger median P-wave (97% greater) and R-wave (56% greater) amplitudes compared to Reveal LINQ.
• The P/R-wave ratio was 36% greater with BM-III, indicating improved signal quality.
• BM-III was more likely to achieve a P-wave amplitude ≥ 0.026 mV (OR 7.47).
• Increasing BMI was negatively associated with P-wave amplitude (OR 0.84), while gender showed no significant association.

Conclusions:

• The longer sensing vector of the BM-III ICM results in superior P-wave and R-wave amplitudes compared to the shorter vector of the Reveal LINQ.
• Both a longer sensing vector and a lower BMI are independently associated with enhanced P-wave visibility, crucial for accurate cardiac monitoring.