Ventricular Complex Electrocardiograms

The ventricular complex (QRS complex) is the part of the electrocardiogram that reflects the electrical activity of the ventricles of the heart. It consists of three teeth: P, Q and R.

The P wave reflects atrial excitation, and the Q and R waves reflect ventricular excitation. The Q wave is negative and occurs before the R wave, and the R wave is positive and occurs after the Q wave.

The QRS complex is an important indicator for diagnosing various heart diseases, such as myocardial infarction, arrhythmias and others. It can also be used to evaluate the effectiveness of treatment and monitor the patient's health.

**Ventricular cardiogram** is a complex of morphological and temporal changes in the heart potential, characterizing bioelectric processes in the ventricular myocardium; spaced from the T waves from the beginning of the P wave to the end of the Q wave at a distance equal to the width of this complex (from several centimeters in children to several millimeters in adults).

Distinctive features of the ventricular complex are a constant QRST coupling interval of about 0.1 sec., constancy in relation to the T teeth and constant width. The Q, S, R waves have a constant amplitude. The length of the PQ, ST, T intervals is not constant and fluctuates for various reasons: slowing or accelerating the conduction of excitation along the atrioventricular pathways, accelerating or slowing down ventricular repolarization, various influences from extracardiac factors.

The PQ interval and QRS complex change during atrial repolarization. In healthy individuals