National Center for Competency Testing (NCCT) Medical Assistant Practice Test

In ECG terminology, a wider than normal QRS complex usually suggests:

1. A heart block

2. A normal rhythm

3. Atrial flutter

4. Sinus rhythm

The correct answer is: A heart block

A wider than normal QRS complex typically indicates that there is a delay in the electrical conduction through the ventricles of the heart, which can occur due to various types of conduction abnormalities, such as a heart block. Specifically, it often suggests that the impulse is not being conducted through the normal pathways, which can lead to a prolonged QRS duration. In the context of ECG interpretation, a normal QRS complex is typically narrow, with a duration of less than 120 milliseconds. When the QRS complex is wider than this, it can indicate issues such as bundle branch blocks, ventricular rhythms (which can happen if the impulse originates in the ventricles), or other ventricular conduction delays. Given this understanding, the association of a prolonged QRS complex with heart block conditions aligns well with known electrophysiological principles in cardiology, making this the correct choice. The other options, which refer to normal rhythms or conditions like atrial flutter and sinus rhythm, do not typically present with a wide QRS complex. Normal rhythms would show narrow QRS complexes, while atrial flutter primarily affects the atrial activity and usually does not alter the width of the QRS, unless there is an underlying conduction delay. Sinus rhythm, representing a normal impulse