Echocardiography evaluation of myocardial strain and ventricular dyssynchrony after implantation of leadless pacemaker Micra AV

ObjectiveTo explore the left and right ventricular myocardial strain and dyssynchrony in patients with Micra AV leadless pacing implantation, and to further analyze the impact of implantation site on myocardial strain and dyssynchrony. MethodsA retrospective study was conducted on 43 patients with Micra AV implantation and 20 patients with high-degree atrioventricular block (Ⅱdegree typeⅡand Ⅲ degree atrioventricular block) at the Department of Cardiology, Zhongshan Hospital from April 2023 to December 2023. The demographic information and clinical characteristics of the patients were collected. Echocardiography and speckle tracking imaging techniques were used to obtain conventional echocardiographic parameters, myocardial strain, and dyssynchrony indices of patients in the two groups, including global longitudinal strain (GLS), free wall longitudinal strain (FWLS), peak strain dispersion (PSD) of 18 left ventricular segments, PSD of 6 right ventricular segments, and other indices. According to the implantation location of Micra AV, the patients were further divided into middle group (right ventricular septum), high group (right ventricular inflow tract), and low group (apical region), and the differences in myocardial strain and dyssynchrony indices among the three subgroups were compared. ResultsThe left ventricular GLS (LVGLS), right ventricular GLS (RVGLS), and right ventricular FWLS (RVFWLS) of the Micra AV group were significantly lower than those of the conduction block group (P＜0.001), and the right ventricular dyssynchrony of the Micra AV group was significantly higher than that of the conduction block group (P＜0.05). Comparison of myocardial strain and dyssynchrony at different implantation sites showed that the LVGLS of the high implantation group was significantly higher than that of the middle and low implantation groups, and the left ventricular dyssynchrony index Yu was significantly lower than that of the middle group (P＜0.05); the right ventricular ejection fraction (RVEF) of the low implantation group was significantly lower than that of the high group, and the right ventricular 6-segment PSD was significantly higher than that of the middle and high implantation groups (P＜0.05). ConclusionsCompared with patients with high-degree atrioventricular block, patients with Micra AV leadless pacing have reduced left and right ventricular strain, and the implantation of low position had greater effect.