Methods for accurate measures of total ventricular activation time.

Area of Science:

• Cardiology
• Biomedical Engineering
• Electrophysiology

Background:

• Cardiac resynchronization therapy (CRT) requires accurate assessment of ventricular activation.
• Current methods for measuring total ventricular activation time (TVAT) may lack precision.
• Improved TVAT measures are crucial for optimizing CRT diagnosis and treatment.

Purpose of the Study:

• To evaluate the accuracy of root mean square (RMS) based QRS width for determining TVAT.
• To assess the utility of electrograms (EGs) from endocardial and epicardial surfaces as indicators of TVAT.
• To identify improved measures for TVAT in the context of CRT.

Main Methods:

• Utilized 96 transmural needle electrodes to record 960 unipolar electrograms (EGs) from six isolated canine hearts.
• Computed RMS-based QRS-widths from endocardial, epicardial, and volumetric EG sets.
• Compared RMS-based QRS-widths against TVAT measured from all 960 EGs.

Main Results:

• No statistically significant differences were observed between RMS-based QRS-widths and true TVAT across all tested EG sets.
• Activation times derived solely from endocardial and epicardial surfaces proved to be inadequate indicators of true TVAT.
• RMS techniques demonstrated reliable accuracy in measuring TVAT.

Conclusions:

• RMS-based QRS-width calculations provide accurate estimations of total ventricular activation time.
• Endocardial and epicardial EGs alone are insufficient for precise TVAT assessment.
• RMS methods are recommended for enhancing TVAT measurements in CRT applications.