INTRODUCTION
Atrial fibrillation (AF)-related functional tricuspid regurgitation (FTR) has been recognized. In AF patients without left heart disease, the prevalence of moderate or severe FTR ranges from 15% to 33.6%[1, 2]. The worsening FTR is associated with more symptoms such as edema, fatigue, exercise intolerance and adverse cardiovascular events[3]. Survival is significantly shorter in patients with moderate or severe FTR, even after adjustment for coexisting conditions[4]. Despite evidence suggesting atrial reverse remodeling and FTR reduction after restoring sinus rhythm[5], a considerable proportion of AF patients developed persistent AF[6, 7], and the FTR progresses over time.
Although the majority of persistent AF patients often manifest a fast heart rate[8], some of them manifest a slow heart rate and are indicated for pacemaker[9]. Irregular rhythm and slow heart rate may contribute to FTR in these patients[10]. As the previous study demonstrated the tricuspid regurgitation (TR) deterioration following a pacemaker[11], the coexistence of AF and a pacemaker may accelerate the FTR deterioration. Right ventricular pacing has shown FTR deterioration in AF patients with bradycardia even in the absence of lead[12, 13], and the main mechanism was considered to be pacing-induced ventricular dyssynchrony[14]. Left bundle branch area pacing (LBBAP) is a physiological pacing method with excellent electrical and mechanical synchrony[15], but the data about FTR in patients with bradycardia responding to LBBAP is rare. The purpose of this study was to explore the change of FTR after LBBAP implantation in patients with persistent AF and bradycardia.