What does a widened QRS complex on an ECG indicate?

A widened QRS complex on an ECG indicates delayed ventricular conduction. The QRS complex represents the electrical activity associated with ventricular depolarization, which is the process that leads to the contraction of the ventricles. When the QRS complex is wider than normal, it typically signifies that the electrical impulses are taking longer to travel through the ventricles, often due to conditions such as bundle branch blocks, ventricular hypertrophy, or other forms of conduction delay.

In a healthy and normal heart, the QRS complex is narrow, reflecting efficient and timely conduction through the ventricular myocardium. Therefore, a widened QRS is an important indicator that there may be underlying issues affecting the heart's conduction system, signaling the need for further evaluation and potential intervention.