More Detailed Increment between Isopotential Lines Reveals New Features of QRS Complex Maps in Healthy Young Population

Group mean isopotential maps of initial parts of ventricular depolarization (QRS complex) in 3 age groups (approximately 10, 14 and 19 years) of young healthy subjects (girls and boys) were analyzed using different increments between isopotential lines. It was found that the increment 0.1 mV masks some features of the maps which are seen only by smaller increment (0.02 mV): the time of appearance of maximum and minimum on the anterior chest, different voltage values of the extrema as normally seen in older subjects, much smaller voltages in the youngest groups compared to the older ones. From this follows that the often applied criterion for the QRS onset - the increasing maximum on the anterior chest - should be reconsidered at least when it concerns the isopotential maps of children.