Optimization of the interventricular delay in cardiac resynchronization therapy using the QRS width.

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Devices

Background:

• Cardiac resynchronization therapy (CRT) optimization is crucial for patient outcomes.
• Interventricular pacing delay (VV) programming is complex and not routinely performed.
• Standardized methods for VV optimization are needed to improve hemodynamic efficiency.

Purpose of the Study:

• To compare acute hemodynamic responses from various VV programming methods in CRT patients.
• To evaluate the efficacy of noninvasive VV optimization techniques against empirical settings.
• To determine the optimal VV delay for maximizing left ventricular (LV) function.

Main Methods:

• Invasive LV dP/dt max measurements were used to assess hemodynamic response.
• Noninvasive electrocardiographic (ECG) and echocardiographic methods were employed for VV optimization.
• Comparison of optimized VV settings against a predefined VV of 0 ms.

Main Results:

• A median LV pre-activation of 30 ms maximized LV dP/dt, significantly increasing it from baseline.
• The noninvasive method selecting the VV for the narrowest QRS width (from earliest deflection) best predicted maximal LV dP/dt.
• This narrowest QRS method significantly improved hemodynamic response compared to the VV of 0 ms setting.

Conclusions:

• Optimizing VV delay using the narrowest QRS width (from earliest deflection) provides superior acute hemodynamic response.
• This method offers a significant improvement over simultaneous biventricular pacing (VV 0 ms).
• Noninvasive VV optimization is a valuable tool for enhancing CRT efficacy.