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Updated: Apr 6, 2026
Evaluation of Left Ventricular Structure and Function using 3D Echocardiography
Published on: October 28, 2020
Evaluation of cardiac function by pacing at different right ventricular sites in patients with third-degree
Qing Zhao1, Jin-Shan Wo1, Jie Guo1
1Departments of Cardiology, Affiliated Hospital of Qingdao University Medical College Qingdao 266003, China.
Insights
Right ventricular outflow tract (RVOT) pacing improves cardiac synchronization and systolic function in patients with third-degree atrioventricular (III-AV) block compared to right ventricular apex (RVA) pacing. RVOT pacing mitigates delays in ventricular contraction and preserves left ventricular function.
Area of Science:
- Cardiology
- Biomedical Engineering
- Medical Imaging
Background:
- Third-degree atrioventricular (III-AV) block can lead to impaired cardiac function and dyssynchrony.
- Pacemaker lead placement in the right ventricle can influence ventricular synchrony and left ventricular function.
Purpose of the Study:
- To compare the effects of right ventricular apex (RVA) pacing versus right ventricular outflow tract (RVOT) pacing on ventricular synchrony and left ventricular function in patients with III-AV block.
Main Methods:
- Doppler echocardiography and electrocardiography were used to assess 38 patients with III-AV block implanted with dual-chamber pacemakers.
- Patients were divided into RVOT (n=20) and RVA (n=18) pacing groups.
- Measurements were taken pre-implantation, and at 1 and 12 months post-implantation.
Main Results:
- No significant baseline differences were observed between groups.
- One month post-implantation, RVA pacing showed prolonged inter-ventricular mechanical delay (IVMD) and septal-to-posterior wall motion delay (SPWMD) compared to RVOT pacing.
- Twelve months post-implantation, RVA pacing resulted in prolonged LVEDD, LVESD, IVMD, SPWMD, and significantly lower LVEF compared to RVOT pacing.
Conclusions:
- RVOT pacing mitigates systolic dysfunction and dyssynchrony compared to RVA pacing in patients with III-AV block.
- RVOT pacing appears to be a superior strategy for maintaining cardiac function and synchrony in this patient population.
Objective:
This study utilized Doppler ultrasonography cardiograms in patients with third-degree atrioventricular (III-AV) block to compare right ventricular apex (RVA) pacing and right ventricular outflow tract (RVOT) pacing with respect to their effects on synchronization of contraction between the two ventricles, as well as on timing of specific left-ventricular electrical and mechanical events and their impact on left ventricular function.
Methods:
Thirty-eight patients with (III-AV) block were implanted with dual-chamber pacemakers, in 20 cases, implantation occurring in the RVOT (RVOT group), while in 18 cases implantation occurred in the RVA (RVA group). Patients underwent Doppler echocardiography and electrocardiography (ECG) one month pre- and one month post-surgery, as well as 12 months post-surgical implantation of the pacemaker.
Results:
Prior to pacemaker implantation, no significant differences were found between the two groups with respect to the following parameters: left ventricular end-diastolic diameter (LVEDD), left ventricular end systolic diameter (LVESD), left ventricular ejection fraction (LVEF), E/A value (ratio of early [E] to late [A] ventricular filling velocities), inter-ventricular mechanical delay (IVMD)and septal-to-posterior wall motion delay (SPWMD). One month after implantation, no significant differences were found between the two groups for LVEDD, LVESD, LVEF, and E/A. However, compared with the RVOT group, the RVA group exhibited prolonged IVMD and SPWMD. Twelve months after pacemaker implantation, there was no significant difference for E/A between the two groups; however, compared with the ROVT group, the RVA group exhibited prolonged LVEDD, LVESD, IVMD, and SPWMD and significantly lower LVEF.
Conclusion:
Relative to RVA pacing, RVOT pacing mitigated impairment of systolic function and systolic dys-synchronization.
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