Cardiovascular Implantable Electronic Devices -> Bradycardia Devices: -> Device Technology D-AB05 - Leadless Pacing: What's Up? (ID 17) Abstract Plus


Background: Accelerometer (ACC)-based AV synchronous (AVS) pacing by tracking atrial contraction (A4) is feasible using a leadless ventricular pacemaker. Previously, low amplitude A4 was identified as a primary factor contributing to low AVS.
Objective: We sought to identify predictors of A4 amplitude.
Methods: The MARVEL 2 study assessed the efficacy of atrial tracking with a temporarily downloaded (up to 5 hours) algorithm into a Micra leadless pacemaker. Baseline medical history, device location, and echocardiogram parameters were assessed in univariate and multivariable regression models with lasso variable selection following multiple imputation for missing data.
Results: The present analysis included 64 (of 75 total enrolled) patients who had visible P-waves on ECG for assessing AV synchrony and A4 amplitude. On a univariate basis, 17 of the 51 candidate predictors were associated with A4 amplitude (P<0.1, Table). Prior CABG, Atrial Contraction Excursion (ACE), E/A ratio, and atrial strain were identified as multivariable predictors in >50% of the 100 imputed datasets. After multivariable analysis, only the echocardiographic measures of atrial function including ACE and E/A ratio remained associated with the A4 amplitude (P=0.001, P=0.088). E/A ratio exceeded 1.5 in 5 of the 15 patients with AVB having ≤90% synchrony and in none of the 25 patients with >90% synchrony.
Conclusion: ACE and E/A ratio were associated with A4 amplitude and may predict a higher percentage of AV synchrony using a single-chamber leadless pacemaker implanted in the right ventricle. Device location had no influence on the A4 signal quality.