QRS 3D voltage-time integral in narrow QRS complex - Establishing the normal reference range.

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Diagnostics

Background:

• Vectorcardiographic 3D QRS voltage-time integral (VTI_QRS-3D) is a novel marker for ventricular dyssynchrony.
• Its clinical utility is being explored, but normal reference ranges in healthy individuals are not yet established.

Purpose of the Study:

• To define the normal reference ranges for VTI_QRS-3D in a healthy adult population.
• To compare VTI_QRS-3D values between healthy individuals and patients with cardiomyopathy.

Main Methods:

• Retrospective analysis of 12-lead ECGs from healthy adults and patients with reduced ejection fraction (EF <50%).
• Conversion of 12-lead ECGs to vectorcardiographic leads using the Kors matrix.
• Calculation of VTI_QRS-3D by integrating the root-mean-square of the 3D voltage over the QRS duration.

Main Results:

• The study included 468 healthy adults and 314 cardiomyopathy patients.
• VTI_QRS-3D was significantly higher in cardiomyopathy patients (48.2 ± 21.4 μVs) compared to healthy individuals (38.1 ± 9.3 μVs).
• In healthy adults, increased age and female sex were associated with lower VTI_QRS-3D. Established reference ranges stratified by age and sex were provided.

Conclusions:

• VTI_QRS-3D values are influenced by age and sex in healthy adults, being higher in younger males.
• Elevated VTI_QRS-3D is observed in patients with cardiomyopathy and reduced EF.
• Age and sex must be considered when utilizing VTI_QRS-3D as a marker for cardiac disease.