Alteration of left ventricular performance by left bundle branch block simulated with atrioventricular sequential...

Area of Science:

• Cardiology
• Electrophysiology
• Cardiac Physiology

Background:

• Atrioventricular (AV) sequential pacing is a common cardiac pacing mode.
• Left bundle branch block (LBBB) can affect left ventricular (LV) function.
• The impact of pacing-induced LBBB on LV performance requires detailed investigation.

Purpose of the Study:

• To evaluate the hemodynamic and angiographic effects of AV sequential pacing-induced LBBB on LV performance.
• To assess changes in LV pressure dynamics and volumes during different pacing modes.

Main Methods:

• Cardiac catheterization was performed in 9 patients with chest pain.
• Left ventricular performance was measured during right atrial pacing and AV sequential pacing at a constant rate (97 ± 3 bpm).
• Hemodynamic parameters (dP/dt, -dP/dt, LVEDP) and angiographic measurements (LVEDV, LVESV, stroke volume, EF) were recorded.

Main Results:

• AV sequential pacing significantly decreased maximal LV pressure increase (dP/dt) and decrease (-dP/dt) (p < 0.001).
• Left ventricular end-systolic volume (LVESV) increased significantly (p < 0.001), leading to reduced stroke volume (-15%) and ejection fraction (-10%).
• Left ventricular end-diastolic pressure (LVEDP) and volume (LVEDV) showed no significant changes.

Conclusions:

• AV sequential pacing can induce LBBB, leading to significant impairment of LV systolic function.
• Reduced ejection fraction and stroke volume indicate a potential negative impact on cardiac output.
• These findings underscore the importance of considering the effects of pacing-induced LBBB on ventricular performance.