Device-detected Atrial Sensing Amplitudes As a Marker of Increased Risk for New Onset and Progression of Atrial High-Rate Episodes

BackgroundAtrial high-rate episodes (AHRE) are frequent in patients with cardiac implantable electronic devices. A decrease in device-detected P-wave amplitude may be an indicator of periods of increased risk of AHRE.ObjectiveTo assess the association between P-wave amplitude and AHRE incidence.MethodsRemote monitoring data from 2,579 patients with no history of atrial fibrillation (23% pacemakers, 77% implantable cardioverter-defibrillators [ICDs] of which 40% providing cardiac resynchronization therapy [CRT]) were used to calculate the mean P-wave amplitude during 1 month after implantation. The association with AHRE incidence according to four strata of daily burden duration (≥15 minutes, ≥6 hours, ≥24 hours, ≥7 days) was investigated by adjusting the hazard ratio with the CHA2DS2-VASc score.ResultsThe adjusted hazard ratio (HR) for 1-mV lower mean P-wave amplitude during the first month increased from 1.10 (95% confidence interval [CI], 1.05-1.15; p<0.001) to 1.18 (CI, 1.09-1.28; p<0.001) with AHRE duration strata from ≥15 minutes to ≥7 days independently of the CHA2DS2-VASc score. Among 871 patients with AHREs, those with 1-month P-wave amplitude <2.45 mV had an adjusted HR of 1.51 (CI, 1.19-1.91; p=0.001) for progression from ≥15 minutes to ≥7 days AHREs compared to those with 1-month P-wave amplitude ≥2.45 mV. Device-detected P-wave amplitudes decreased linearly during the one year before the first AHRE by 7.3% (CI, 5.1%-9.5%, p<0.001 versus patients without AHRE).ConclusionDevice-detected P-wave amplitudes lower than 2.45 mV were associated with an increased risk of AHRE onset and progression to persistent forms of AHRE independently of the patient’s risk profile.