Objective Investigating the impact of Micra AV leadless pacemaker implantation sites on patients' atrioventricular synchrony

cardiac structure

and function. Methods A total of 80 patients with third-degree atrioventricular block admitted to the Hospital from April 2023 to April 2025 were selected. All patients received MicraAV leadless pacemaker implantation and were observed for 3 months postoperatively. According to the implantation site

the patients were divided into high septal group and low septal group

with 40 patients each. The atrioventric

ular synchronization rate

pacing QRS wave width

electrical parameters （threshold

R-wave amplitude

resistance parameters）

cardiac structural indexes [left ventricular ejection fraction (LVEF)

incidence of tricuspid regurgitation

]

and cardiac function grade [New York Heart Association (NYHA) grade

]

were compared between the two groups immediately after surgery

one month after surgery

and three months after surgery

and the incidence of readmission during the observation period. Results Compared with the patients in the low interval group

the atrioventricular synchronization rate

R-wave amplitude and LVEF levels were higher in the high interval group immediately after surgery

one month after surgery and three months after surgery

and the pacing QRS wave width was narrower (

P

<

0.05). There were no significant differences in the threshold values and resistance parameters between the two groups at different postoperative periods (

P

>

0.05). Tricuspid regurgitation occurred in both groups at one month and three months after surgery

but the symptoms were mild and worsened

and there was no significant difference in the incidence between the two groups (

P

>

0.05). At three months after surgery

the NYHA grade of patients in the high interval group was better than that in the low interval group (

P

<

0.05). During the observation period

the readmission rate of patients in the high interval group was lower than that of patients in the low interval group (

P

<

0.05). Conclusions MicraAV high-interspaced implantation of leadless pacemaker in the treatment of atrioventricular block has narrow pacing QRS wave and high R-wave amplitude

and can increase the atrioventricular synchronization rate without increasing the incidence of tricuspid regurgitation

and can improve cardiac function and reduce readmission rate

which is significantly better than low-interval implantation.