VDD leadless pacemaker: atrioventricular synchrony predictors

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Leadless pacemaker technology has shown a reduction of the complications associated with conventional pacemakers. The development of the VDD mode has allowed us to extend the use of leadless pacemakers to patients in need of pacing due to atrioventricular (AV) block. Maintaining AV synchrony (AVS) in cardiac pacing improves cardiac output and quality of life and reduces the risk of atrial fibrillation (AF) and pacemaker syndrome. In previous analyses, it was observed that the low amplitude of the A4 signal was associated with low AVS. Methods Prospective single-center study of consecutive patients who received a VDD leadless pacemaker (Micra AV), and who remained in VDD mode throughout the follow-up. Our purpose was to analyze the possible predictors of A4 signal amplitude and AVS in the first month of follow-up. We tested univariate association with A4 signal and AVS of echocardiographic data, clinical variables, implant parameters, and pacemaker function. Results We included data from the first 21 patients who received a VDD leadless pacemaker (Micra AV) between Jun/20 and Apr/21. 18 patients remained in VDD mode after the first month of follow-up. There was no significant association between ventricular filling waves (E and A) and Tissue-Doppler diastolic waves (E ’and A’) with the A4 signal and the percentage of AVS. Only the E / A ratio showed a trend of association with the percentage of AVS, although it did not reach statistical significance (p = 0.09), showing an inverse relationship (Pearson’s correlation coefficient of -0.396). None of the clinical variables analyzed showed an association with the A4 signal or with the percentage of AVS. Only the A4 signal was significantly associated with the percentage of AVS (Pearson´s correlation coefficient of 0.524, p = 0.02). Considering 85% as an adequate discriminator for correct AVS, the mean signal of A4 was significantly lower (p = 0.03) in those with AVS < 85% (2.63 ± 1.73) compared with those with AVS≥85% (4.37± 1.34). Regarding implant factors, there seems to be a tendency to worse AVS with higher number of releases (p = 0.06, Pearson’s correlation coefficient of -0.460), as well as when implanting in positions further away from the atrium (medium interventrcular septum vs. high interventricular septum / proximal right ventricular outflow tract; p = 0.06, Pearson’s correlation coefficient of -0.463). Conclusions Although this is a short case series, our results are aligned with the data from the MARVEL2 AVS predictors substudy. It appears that the main predictor of higher AVS is the A4 signal. Device position, as well as the number of releases, could also play a role. Nevertheless, it is necessary to continue the analysis with the data of future patients to corroborate these preliminary findings.