What is a characteristic of a broad QRS complex on an ECG?

A broad QRS complex on an ECG is typically characterized by a duration that exceeds 120 milliseconds (which is equivalent to more than 3 small squares on the standard ECG paper that measures 1 millimeter per square). This finding indicates a delay in ventricular depolarization, which could result from various conditions such as bundle branch blocks, ventricular hypertrophy, or other forms of intraventricular conduction delays.

Understanding QRS duration is vital in assessing cardiac function and rhythm abnormalities. When the QRS complex is widened, it suggests that the electrical conduction through the ventricles is altered, and it may also signal severe cardiac issues that require immediate evaluation and intervention. Hence, identifying a QRS duration as being more than 3 small squares (which corresponds to the normal threshold for a narrow QRS complex) aligns with the criteria used in clinical practice to diagnose potential cardiac disturbances.