Altered left ventricular contraction pattern during right ventricular pacing: assessment using real-time...

Area of Science:

• Cardiology
• Medical Imaging
• Biomedical Engineering

Background:

• Chronic right ventricular apical (RVA) pacing is linked to heart failure and adverse outcomes.
• The acute effects of RVA pacing on ventricular function and mechanical dyssynchrony are not well understood.
• Real-time 3D echocardiography (RT3DE) is utilized to investigate these acute effects.

Purpose of the Study:

• To assess global and regional left ventricular (LV) function during RVA pacing using RT3DE.
• To evaluate changes in LV mechanical dyssynchrony and contraction patterns induced by RVA pacing.

Main Methods:

• Twenty-six patients with pacemakers and normal conduction underwent RT3DE during sinus rhythm and RVA pacing.
• LV function and mechanical dyssynchrony were quantified using time-volume analysis and the systolic dyssynchrony index (SDI).
• Longitudinal function was assessed across apical, midventricular, and basal segments.

Main Results:

• RVA pacing induced a reversed apical-to-basal longitudinal contraction sequence in 58% of patients.
• Significant increases in LV dyssynchrony (SDI) were observed during RVA pacing (4.4% to 6.3%, P=0.001).
• LV ejection fraction decreased during RVA pacing (53% to 47%, P=0.05).

Conclusions:

• RT3DE demonstrates that RVA pacing acutely alters LV contraction sequence and increases mechanical dyssynchrony.
• These findings suggest RVA pacing can lead to adverse LV remodeling and dysfunction.
• Further research using RT3DE may help identify patients at risk for pacing-induced heart failure or benefiting from alternative pacing strategies.