Ventricular interdependence in patients with dual-chamber pacing: a Doppler tissue imaging study

Area of Science:

• Cardiology
• Biomedical Engineering
• Diagnostic Imaging

Background:

• Pacemakers (PM) are crucial for managing heart rhythm disorders like atrioventricular (AV) block.
• Optimizing pacemaker settings is essential for maintaining adequate cardiac function and patient well-being.
• Understanding ventricular interaction is key to improving pacing strategies.

Purpose of the Study:

• To analyze pulsed-Doppler tissue imaging (DTI) of the right ventricular (RV) and left ventricular (LV) annuli in patients with pacemakers.
• To compare DTI parameters in DDD mode patients with healthy subjects.
• To investigate the physiologic interaction between the RV and LV in pacemaker patients under different pacing modes.

Main Methods:

• 22 pacemaker patients and 20 healthy controls were studied.
• Standard echo Doppler and DTI parameters were measured at baseline and during DDD pacing at varying heart rates and AV delays.
• Left ventricular (LV) stroke volume was assessed using the LV outflow Doppler method.

Main Results:

• Pacemaker patients showed significantly higher peak systolic (S(m)) and early diastolic (E(m)) wall velocities in both RV and LV annuli compared to controls.
• LV stroke volume strongly correlated with RV E(m) and S(m) peak velocities (r=0.83 and r=0.81, respectively).
• RV DTI parameters independently predicted LV stroke volume, highlighting significant RV-LV interaction.

Conclusions:

• Pulsed-DTI effectively demonstrates physiologic ventricular interaction in pacemaker patients.
• DTI serves as a valuable tool for predicting LV systolic performance.
• DTI can aid in selecting the most appropriate pacing mode for individual pacemaker patients.