Patient population
A total of 1,670 patients who underwent a single ventricular or dual-chamber transvenous PPM implantation at our hospital between January 2003 and December 2017 were included in this study. Patients with prior valvular surgery, HF and left ventricular ejection fraction (LVEF) <50%, dilated cardiomyopathy, hypertrophic cardiomyopathy, and preexisting abnormal (mild-moderate, moderate or severe) TR and abnormal (>30 mmHg) TRPG were excluded. Patients without follow-up records for PPM and without complete follow-up echocardiography were also excluded (Figure 1). Finally, a total of 1,075 patients were enrolled in this study and were divided into two groups: group 1 consisted of 198 patients with increased degree of post-implant TR (≥2 degrees) and/or abnormal TRPG and group 2 consisted of 877 patients without increased degree of post-implant TR and abnormal TRPG. Patients with dual-chamber PPM implantation underwent pacing in the dual chamber rate-adaptive mode, whereas patients with single ventricular PPM implantation underwent pacing in the ventricular-inhibited rate-adaptive mode. General demographics, comorbidities, lead positions, pacing QRS durations, pacing percentages, echocardiographic parameters, HF hospitalization, and cardiovascular and all-cause mortality were compared between the groups.