Abnormally slow depolarization of the ventricles would most change the shape of the QRS complex in an ECG tracing.
The conduction system in the ventricles depolarizes, and this depolarization spreads along the walls of the ventricles to produce the QRS complex.
It represents electrical activity that occurs before the ventricles contract (ventricular systole). The QRS complex appears immediately after the onset of ventricular systole.
An aberrant depolarization of the ventricles results in the formation of an abnormal QRS complex.
The SA node, an ectopic pacemaker in the atria, AV junction, bundle branches, Purkinje network, or the ventricular myocardium are all possible pacemaker sites in these aberrant QRS complexes.
An aberrant QRS complex might have any shape, from normal to wide and odd to slurred and notched.
