Study of right atrial and right ventricular function in dual chamber pacemaker patients
Authors: Abdelgawad H , Hassanin M , Sadaka M , Ibrahim Sanhoury M , Saeed Ahmed Abbas R 
Published: October 2024

Abstract

Background
Unlike left ventricular function, right ventricular (RV) function in pacemaker patients is less well studied with less studies comparing septal versus apical pacing effects on the RV function and almost none on the right atrial (RA) function.

Purpose
To assess the effect of RV pacing on the echocardiographic and clinical parameters of the RV and RA function and their correlation with the site of right ventricular lead implantation.

Methods
The study assessed 59 patients in need of permanent dual chamber pacemaker implantation using clinical and echocardiographic data of the RV and RA size and function using tricuspid annular plane systolic excursion (TAPSE), S wave velocity of the tricuspid annulus and fractional area change (FAC), free wall strain (FWSL), global longitudinal strain (GLS) of the RV, RA strain including reservoir, conduit and contraction phases and 3D ejection fraction of the RV using Epiq 7 Ultrasound machine (Philips Healthcare) by the same echocardiographer before implantation and 6 months after. All programming parameters were recorded postoperative and 6 months later.

Results
31 patients had the RV lead in the RV apex whereas 28 had it in the septum and all patients had their RA lead in the right atrial appendage, with no significant difference between both groups regarding baseline demographic, clinical nor echocardiographic data. At 6 months, there was a significant decline of the 3D RVEF from a mean of (58.57% ± 6.35%) to (56.41% ± 6.17%), TAPSE from (2.61 cm ± 0.51) to (2.35 cm ± 0.52) and S wave from (13.73 cm/sec ± 2.84) to (12.64 cm/sec ± 2.61) but none showed a significant difference between septal and apical pacing, on the other hand, the RV strain showed a significant decline 6 months after implantation in both the FWSL from (-31.75% ± 5.39) to (-27.82% ± 5.73) and the GLS from (-25.89% ± 5.17) to (-21.65% ± 4.51) with more decline in the septal group compared to the apical (-20.33% ± 4.70 versus -22.84% ± 4.04 regarding the GLS and -26.11% ± 6.41 versus -29.37% ± 4.62 in the FWSL, respectively). There was no difference in the FAC, tricuspid regurgitation severity, gradient nor the estimated pulmonary artery pressure at 6 months. The RA size showed a significant decline at 6 months but no difference in any of the strain parameters. No clinical RV failure symptoms nor signs were observed. Programming revealed a mean percentage of ventricular pacing of (97.92% ± 2.67%) with a minimum of 91% and atrial pacing of (10.41% ± 12.52%), and the thresholds, impedance and atrial high-rate episodes were comparable postoperatively and 6 months after, with no difference between the septal and apical groups.

Conclusion
At 6 months follow-up after pacemaker implantation, right ventricular function starts to show decline in both the septal and apical groups with only the right ventricular strain more affected in the septal group compared to the apical.3D right ventricular ejection fraction3D right ventricular strain