Although the deleterious effects of chronic right ventricular (RV) pacing on left ventricular (LV) function were largely studied and proven, a limited number of studies tackled the effect on RV function.
Echocardiographic assessment of the right ventricle is complex. 3D right ventricular ejection fraction (RV EF) and right ventricular global longitudinal strain (RV GLS) had good correlation with the gold standard cardiac magnetic resonance assessment of the RV EF more than conventional parameters. ,,
Our study included 59 patients who presented to Alexandria Main University Hospital from 2021 to 2023 with high grade atrioventricular block with normal preprocedural RV function according to ASE guidelines. We excluded patients with left ventricular ejection fraction less than 50%, proven coronary artery disease, previous cardiac surgery, pulmonary hypertension, and severe tricuspid regurgitation.
We assessed every patient’s clinical data including age, sex and risk factors and each had a standard echocardiographic study before implantation and 6 months after, done using an Epiq CVx Ultrasound machine (Philips Healthcare, Eindhoven, Netherlands) according to the ASE guidelines. Analysis was generated using the TOMTEC software (TEC Imaging Systems GmbH, Munich, Germany) with manual adjustment if needed.
The studied parameters included Tricuspid annular plane systolic excursion (TAPSE), S’ wave velocity, fractional area change (FAC) by 2D imaging, RV E/e’, RV end diastolic volume, end systolic volume and ejection fraction by 3D echocardiography, right atrial maximum, minimum diameters and area by 2D imaging as well as assessment of the Tricuspid regurgitation severity and gradient.
To assess the right ventricular and atrial strain, images were acquired in RV focused 4-chamber view as recommended by the EACVI/ASE/Industry consensus document.
The 2D RV strain parameters assessed were the free wall longitudinal strain (FWSL) and the global longitudinal strain (GLS), whereas the right atrial parameters were the reservoir, conduit and contractile phases.
All right atrial leads were implanted in the right atrial appendage; the right ventricular lead was either implanted in the interventricular septum in 28 patients or the RV apex in 31 patients according to the operator preference.
Statistical analysis of the obtained data was performed using the IBM SPSS software package version 20.0. (Armonk, NY).
The patients’ mean age was 60.75 ± 12.22 years and 66% of the study patients were females. 72.9% of our patients were hypertensive, 30.5% were diabetics. None of the previous demographic data showed a significant difference between both groups.
On follow up, our patients had a ventricular pacing percentage of 97.92 ± 2.67% and an atrial pacing percentage of 10.41 ± 12.52%.
All measured echocardiographic parameters showed no significant difference between the septal and the apical pacing groups at the baseline preimplantation assessment.
On follow up, TAPSE showed a significant decline in the total population of the study (2.61 ± 0.51 cm to 2.35 ± 0.52 cm; p <0.001) that was similar in both groups, the same applied to the S’ wave (13.73 ± 2.84 cm/sec to 12.64 ± 2.61 cm/sec; p = 0.010). However, the FAC and the RV E/e’ showed no significant change overtime.
The 3D assessment of the right ventricle showed a significant decline in the ejection fraction (58.57 ± 6.35% to 56.41 ± 6.17%; p = 0.029). Twenty patients had a decline of their 3D RVEF of more than or equal 5%.
The RV free wall strain decreased from −31.75 ± 5.39% to −27.82 ± 5.73% with a p value of less than 0.001 and the RV global longitudinal strain from −25.89 ± 5.17% to −21.65 ± 4.5% with a p value of less than 0.001 and the values were significantly less in the septal pacing group versus the apical pacing group −26.11 ± 6.41% versus −29.37 ± 4.62%, respectively, with a p value of 0.028 as seen in Figure 1 .
Right ventricular global and free wall strain values at baseline and after 6 months in the total population of the study, septal and apical pacing groups.
On correlating the QRS width of the paced rhythm with the 3D RVEF and FWSL, no significant correlation was found.
Regarding the right atrium, there was a significant decrease in the right atrial maximum diameter and area. There was no significant change over time in any of the right atrial strain phases. The 3 strain functions are prognostic in pulmonary hypertension patients, and the reservoir function of the right atrial strain phases correlates with the right atrial pressure. ,
There was no significant change of the tricuspid regurgitation severity nor gradient over time with no difference between both groups.
Detailed description of the previously reported findings can be seen in Table 1 .
Table 1
Changes in the RA and RV echocardiographic parameters from baseline to 6 months after implantation and comparsion of these findings between the septal and apical groups at 6 months
| Changes in the RA and RV echocardiographic parameters from baseline to 6 months after implantation (Values in mean and SD) | |||
|---|---|---|---|
| Parameter | At baseline | 6 months after implantation | p value |
| RV base (mm) | 40.37 ± 7.17 | 35.56 ± 6.09 | <0.001 |
| 3D RV EDV (mL) | 118.6 ± 33.39 | 104.3 ± 33.0 | 0.005 |
| TAPSE (cm) | 2.61 ± 0.51 | 2.35 ± 0.52 | <0.001 |
| S wave (cm/sec) | 13.73 ± 2.84 | 12.64 ± 2.61 | 0.01 |
| FAC (%) | 51.44 ± 6.28 | 51.65 ± 5.84 | 0.84 |
| RV E/e’ | 5.43 ± 2.60 | 5.12 ± 2.13 | 0.64 |
| 3D RVEF (%) | 58.57 ± 6.35 | 56.41 ± 6.17 | 0.029 |
| RV GLS (-%) | 25.89 ± 5.17 | 21.65 ± 4.51 | <0.001 |
| RV FWSL (-%) | 31.75 ± 5.39 | 27.82 ± 5.73 | <0.001 |
| RA max. diameter (mm) | 51.39 ± 7.20 | 49.07 ± 7.15 | 0.016 |
| RA min. diameter (mm) | 40.13 ± 6.32 | 38.78 ± 6.89 | 0.1 |
| RA area (mm 2) | 17.26 ± 4.93 | 15.69 ± 4.66 | 0.014 |
| RA reservoir (%) | 29.70 ± 10.36 | 27.89 ± 7.15 | 0.2 |
| RA conduit (-%) | 19.89 ± 8.58 | 17.66 ± 7.72 | 0.127 |
| RA contractile (-%) | 10.01 ± 6.84 | 10.55 ± 5.39 | 0.54 |
| Septal versus apical groups’ echocardiographic parameters at 6 months after implantation | |||
| Parameter | Septal group | Apical group | p value |
| RV base (mm) | 34.08 ± 5.54 | 36.90 ± 6.34 | 0.075 |
| 3D RV EDV (mL) | 102.9 ± 31.40 | 105.6 ± 34.85 | 0.759 |
| TAPSE (cm) | 2.28 ± 0.42 | 2.42 ± 0.60 | 0.325 |
| S wave (cm/sec) | 12.41 ± 2.26 | 12.85 ± 2.91 | 0.524 |
| FAC (%) | 51.19 ± 6.16 | 52.05 ± 5.62 | 0.576 |
| RV E/e’ | 4.75 ± 1.44 | 5.45 ± 2.57 | 0.43 |
| 3D RVEF (%) | 56.21 ± 6.93 | 56.58 ± 5.50 | 0.82 |
| RV GLS (-%) | 20.33 ± 4.70 | 22.84 ± 4.04 | <0.03 |
| RV FWSL (-%) | 26.11 ± 6.41 | 29.37 ± 4.62 | <0.028 |
| RA max. diameter (mm) | 48.40 ± 6.24 | 49.68 ± 7.93 | 0.498 |
| RA min. diameter (mm) | 36.70 ± 6.57 | 40.65 ± 6.73 | 0.026 |
| RA area (mm 2) | 14.83 ± 3.83 | 16.47 ± 5.24 | 0.18 |
| RA reservoir (%) | 26.80 ± 6.77 | 28.86 ± 7.46 | 0.273 |
| RA conduit (-%) | 16.55 ± 7.16 | 18.67 ± 8.17 | 0.298 |
| RA contractile (-%) | 10.37 ± 5.0 | 10.72 ± 5.80 | 0.933 |
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
