Physiological Variability of Ventricular Activation Time Maps

Abstract Background Ventricular activation time (VAT) based on intrinsicoid deflection is an electrocardiographic parameter that measures the time from the start of the QRS complex to the peak of the R wave. Objectives Analysis of body surface isochrone VAT maps as an extension of VAT in single leads in a healthy young population from the point of view of physiological variability according to sex and age. Methods VAT maps were registered and analysed in 178 healthy volunteers using the mapping system ProCardio. Results Statistically significant differences were found in the activation begin, arithmetic and quadratic mean, median decreasing with age, while its duration and standard deviation increased with age. Mean VAT maps showed that activation typically begins in the upper right chest and ends in the upper back, with a predominantly counter-clockwise spread. There were no significant differences in mean map patterns. This also concerns the map areas corresponding to the minimum and maximum activation times, as well as the no-R wave areas. All of them were located outside the positions of standard chest electrodes. Conclusions The use of VAT isochrone maps can help identify the location of the beginning and end of ventricular activation, the activation sequence on the chest surface, and different values of selected quantitative parameters due to age and sex to differentiate between pathology and physiological variability.