Optimal sensed atrio-ventricular interval determined by paced QRS morphology

Area of Science:

• Cardiology
• Biomedical Engineering

Background:

• Cardiac resynchronization therapy (CRT) requires optimization of atrio-ventricular (AV) and interventricular (VV) intervals for maximal efficacy.
• Determining optimal paced AV (PAV) and sensed AV (SAV) intervals is crucial for CRT optimization.
• This study investigates using QRS morphology to determine optimal SAV in patients with normal AV conduction.

Purpose of the Study:

• To test the hypothesis that QRS morphology at the optimal PAV can predict the optimal SAV interval.
• To establish a non-invasive method for optimizing SAV in CRT patients.
• To improve CRT device programming and patient outcomes.

Main Methods:

• 16 patients with implanted CRT devices underwent invasive optimization of PAV and VV intervals using LV dP/dt(max).
• 12-lead ECGs were recorded at optimal settings.
• SAV interval was adjusted during atrial sensing ventricular pacing to match QRS morphology with the optimal PAV, verified by LV dP/dt(max).

Main Results:

• Optimization of PAV and VV intervals significantly increased LV dP/dt(max) by 23% (P = 0.0000002).
• The optimized SAV interval (100 ± 20 ms) resulted in a 21% increase in LV dP/dt(max) (P = 0.000004).
• The mean difference between optimized PAV and SAV was 49 ± 17 ms.

Conclusions:

• QRS morphology during optimal PAV serves as a reliable template for determining the optimal SAV interval.
• This method is effective in patients with normal AV conduction.
• This finding simplifies and potentially enhances the optimization process for CRT.