[Effect of ventricular and sequential stimulation on the left- ventricular systolic function].

Area of Science:

• Cardiology
• Biomedical Engineering
• Cardiac Electrophysiology

Context:

• Assessment of left ventricular systolic function in patients with second and third-degree atrioventricular (A-V) block.
• Evaluation of hemodynamic performance following dual chamber pacemaker implantation.
• Comparison of VVI (single chamber ventricular pacing) and DDD (dual chamber pacing) modes.

Purpose:

• To determine the hemodynamic superiority of DDD pacing over VVI pacing in patients with A-V block.
• To assess the impact of varying atrio-ventricular (A-V) intervals on left ventricular systolic function during DDD pacing.
• To identify optimal A-V intervals for maximizing cardiac output.

Summary:

• Hemodynamic measurements including stroke volume index (SVI) and cardiac index (CI) were taken in 20 patients using echocardiography and Doppler.
• Patients were paced in VVI and DDD modes with A-V intervals of 100, 150, and 200 ms.
• DDD pacing demonstrated significant hemodynamic advantages over VVI pacing, with optimal CI achieved through individualized A-V interval programming.

Impact:

• DDD pacing significantly enhances left ventricular systolic function at rest compared to right ventricular pacing in patients without heart failure symptoms.
• Individualized programming of A-V delay during DDD stimulation is crucial for achieving maximal hemodynamic benefits.
• Findings support the use of DDD pacing and patient-specific A-V interval optimization for improved cardiac performance.