Differences in Tricuspid Valve Insufficiency, Mechanical Synchrony, and Cardiac Remodeling Between Left Bundle Branch...

Cardiac implantable electronic device-induced tricuspid regurgitation (CIED-induced TR) involves primary (lead-induced) and functional etiologies. The impact of left bundle branch area pacing (LBBAP) versus right ventricular pacing (RVP) on these mechanisms remains unclear.

To compare the incidence and mechanisms of TR among pacing modalities, and evaluate the prognostic significance of these mechanisms.

We analyzed 225 patients with first-time RV apical pacing (RVAP, n=97) or RV septal pacing (RVSP, n=78) using stylet-driven leads, and LBBAP (n=50) using lumenless leads. Echocardiography and electrocardiography were performed at baseline and 2 years post-implantation. Three-dimensional echocardiography assessed lead interference. Kaplan-Meier analysis compared event-free survival between lead-induced (LITR) and functional TR (FTR) groups. Cox regression identified predictors for adverse outcomes.

Despite a higher baseline heart failure burden than RVP (P< .001), LBBAP showed the lowest TR progression rate (20.0% vs RVAP 43.3% vs RVSP 35.9%, P=.020) over 25.8 months. Mechanistically, LBBAP shortened QRS duration (vs RVP widening, P< .001) and demonstrated less lead interference than RVAP (28.0% vs 50.5%, P= .009). Furthermore, LBBAP showed greater left-heart reverse remodeling and improvement in mitral regurgitation, while preserving right-heart structure and function better than RVP. Over 37.4 months, LITR showed worse outcomes than FTR (P= .03). LITR, pulmonary hypertension, reduced left ventricular ejection fraction, and elevated creatinine were independent predictors for adverse outcomes.

LBBAP was associated with less CIED-induced TR than RVP, likely through reduced mechanical interference, superior electrical synchrony, and favorable cardiac remodeling. Furthermore, LITR was associated with a worse prognosis than FTR.