210 Does Length of Sensing Vector Matter on the Detection of P- and R- Wave Amplitude in Insertable Cardiac Monitors?

Abstract

P-wave visibility is useful for diagnosis of atrial arrhythmias via insertable cardiac monitors (ICM). To compare the sensing capability of ICM with different vector length: Medtronic REVEAL LINQ (45mm) vs Biotronik Biomonitor BMIII (75mm). We accessed de-identified Australian remote monitoring transmissions from n=40 patients with BMIII from Biotronik for comparison with n=80 gender- and body mass index (BMI)-matched patients with REVEAL LINQ. Digital measurement of calibrated ICM electrograms was performed using DigitizeIt© (V2.3.3, Germany) of 5 consecutive P-QRS complexes by 3 investigators independently. P-wave amplitude was measured from baseline to peak and R-wave amplitude was measured from peak-to-peak. Further, we evaluated the impact of BMI on Pwave visibility. Patients in both groups are well matched for gender and BMI (53% male, mean BMI 26.7 kg/m2; both p=NS). P-wave and R-wave amplitude were 89% & 20% larger in the BMIII vs LINQ (0.072±0.039 vs 0.038±0.022mV, p=0.0001; & 0.83±0.42 vs 0.69±0.45mV, p=0.095) respectively. Multivariate regression analysis showed that increasing BMI (figure), female gender and LINQ were independently associated with lower P-wave amplitude (all p<0.001). Inter-operator reproducibility of P-wave measures was very good (ICC 0.91, p<0.001). The longer ICM sensing vector of BMIII yielded considerable larger P-wave amplitude than LINQ, that was not impacted by increasing BMI. Better P-wave visibility may improve clinical decision-making after device detected arrhythmias.