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 promising for cardiac resynchronization therapy, but normal reference ranges are undefined.
• Establishing these ranges is crucial for accurate interpretation.

Purpose of the Study:

• To define the normal reference ranges for VTI_QRS-3D in a healthy adult population.
• To investigate the influence of age and sex on VTI_QRS-3D values.
• To provide a basis for using VTI_QRS-3D as a diagnostic marker.

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 for QRS duration ≤120 ms.
• Calculation of VTI_QRS-3D and determination of reference ranges (2.5th-97.5th percentiles) stratified by sex and age groups.

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) versus healthy individuals (38.1±9.3 μVs).
• Increased age and female sex were significant predictors of lower VTI_QRS-3D in healthy individuals, with established age- and sex-specific reference ranges.

Conclusions:

• VTI_QRS-3D is higher in younger individuals, males, and patients with reduced ejection fraction cardiomyopathy.
• Age and sex must be considered when interpreting VTI_QRS-3D values.
• Defined reference ranges facilitate the clinical application of VTI_QRS-3D for detecting structural heart disease.