QRS complex: abnormally enlarged shape

2021-06-01 02:17 PM

The QRS complex is considered abnormal when it lasts less than 0.09s; when it dilates for more than 0.12s- this is caused by a block in some part of the heart's conduction system.

Widened QRS complex: myocardium is dilated or enlarged

The QRS complex widens during ventricular depolarization, so the prolongation of the time it takes the impulse to travel through the ventricles often causes the QRS complex to widen. This dilation usually occurs when one or both ventricles are enlarged or dilated, prolonging the path of the impulse through the ventricles. The normal QRS complex dilates 0.06-0.08s, while the myocardium is dilated or hypertrophied, the QRS complex can widen to 0.09 to 0.12s.

Widened QRS complex: Purkinje network block

When the Purkinje network is blocked, the heart's impulses must travel through the ventricular muscle instead of through the Purkinje network. This reduces the pulse transmission rate to about one-third of normal. Thus, if a branch is blocked, the QRS complex duration usually increases to 0.14s or more.

The QRS complex is considered abnormal when it lasts less than 0.09s; when it dilates for more than 0.12s- this is caused by a block in some part of the heart's conduction system.

Widened QRS complex: cause of irregular shape

The abnormal shape of the QRS complex is largely due to two causes: (1) destruction of the myocardium in different regions of the ventricles, with replacement by scar tissue, and (2) multivessel block small of the Purkinje network. The result is abnormal transmission of impulses by the heart, causing potential changes and potential deviations. This abnormality usually causes 2 or 3 peaks on several ECG leads.