Effect of chronic right ventricular apical pacing on left ventricular function.

Area of Science:

• Cardiology
• Nuclear Medicine
• Medical Imaging

Background:

• Left ventricular ejection fraction (LVEF) changes in patients with baseline impaired function are not well understood.
• Assessing determinants of LVEF change is crucial for managing heart failure.

Purpose of the Study:

• To identify key factors influencing changes in left ventricular ejection fraction (LVEF) over time.
• To determine predictors for LVEF improvement and decline in patients with reduced baseline LVEF.

Main Methods:

• Retrospective analysis of a nuclear database including patients with baseline LVEF 25-40%.
• Inclusion criteria required a follow-up gated single-photon emission computed tomographic study approximately 18 months later.
• Patients were categorized into EF increase (> or =10 points) or EF decrease (> or =7 points) groups.

Main Results:

• Beta-blocker therapy was the strongest predictor of LVEF improvement (odds ratio 3.9, p=0.002).
• Permanent right ventricular apical pacemaker use was the strongest independent predictor of LVEF decrease (odds ratio 6.6, p=0.002).
• The EF increase group showed an average LVEF rise from 33% to 51%; the EF decrease group showed a drop from 35% to 25%.

Conclusions:

• Beta-blocker therapy is a major independent predictor for significant LVEF improvement.
• Permanent right ventricular apical pacing is the strongest predictor for significant LVEF decrease.
• These findings highlight distinct therapeutic and device-related influences on LVEF dynamics.