Estimation of the optimal VV delay by an IEGM-based method in cardiac resynchronization therapy

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Devices

Background:

• Cardiac resynchronization therapy (CRT) optimization relies on interventricular (VV) delay.
• Current VV delay determination uses echocardiography (ECHO), which is costly and time-consuming.
• Intracardiac electrogram (IEGM) signals offer a potential alternative for VV delay assessment.

Purpose of the Study:

• To evaluate the performance of a novel IEGM-based VV delay optimization method.
• To compare the IEGM-based method against the established aortic velocity time integral (AVTI) method using ECHO.
• To assess the accuracy and concordance of VV delay optimization between IEGM and ECHO methods.

Main Methods:

• Two patient groups were studied: 11 in a prospective trial (Rhythm II ICD) and 61 in a retrospective trial (RHYTHM VV).
• Interventricular (VV) delay was optimized using both IEGM and ECHO-based AVTI methods.
• Comparisons were made between maximum AVTI values obtained from both optimization techniques.

Main Results:

• Prospective study: Maximum AVTI by ECHO (24.3 cm) closely correlated with IEGM-based AVTI (23.9 cm; CCC=0.99).
• Retrospective analysis: ECHO-determined maximum AVTI (22.1 cm) was similar to IEGM-based AVTI (20.9 cm; CCC=0.98).
• Both prospective and retrospective analyses showed high concordance between the IEGM and ECHO methods.

Conclusions:

• The IEGM-based VV delay optimization method demonstrates high accuracy and concordance with ECHO-based AVTI.
• This IEGM method presents a viable, potentially more efficient alternative for optimizing VV delay in CRT.
• Further validation may support the clinical adoption of IEGM for CRT optimization.