[Training-induced changes of reference vectors in the QRS complex of the EKG of young trotting horses].

The research investigates how training influences the changes in the QRS complex (part of EKG that represents the depolarization of the ventricles) vector properties in young standardbred horses. The observed changes in vectors take place in two stages, related to the peculiarities of the training process.

Vector Changes in the QRS Complex

• The researchers focused on the changes in vectors within the QRS complex, a portion of an EKG reading that represents the heart’s ventricles’ depolarisation – ‘exciting’ them to contract and pump blood.
• These vector changes are grouped into two main stages, characterized by the timeline of the training program.

First Stage of Changes

• The first stage of changes happens within the first three months of training also known as “breaking.” The vector R (VR) in limb leads, which represent the electrical currents travelling through the four chambers of the heart, moves towards the left, and in the direction of the rear (caudal) and the back (dorsal).

Second Stage of Changes

• The second change happens between the fifth and the seventh month after breaking. The S vector (VS) shifts upward (cranial).
• This shift in vector positions, especially the movement of the VS vector upwards, is considered to be primarily influenced by the character of the training programs conducted in these respective stages.
• The study couldn’t find any substantial indicators that these changes are directly related to age or development factors. The shifts seem to occur in direct relation to the onset and nature of the training program.

Implication of Findings

• The findings imply that the physical training regimen of young standardbred horses can substantially manipulate the electrical depiction of heart activity, primarily the directions and magnitudes of vectors within the QRS complex.
• Understanding these shifts may provide essential insights into the impact of training on cardiovascular health and performance in these horses, which can assist in optimizing their training regimens and monitoring their health status.