In which situation would you most likely see a QRS complex that is wide?

The presence of a wide QRS complex is characteristic of ventricular tachycardia. This arrhythmia originates in the ventricles and is defined by the heart beating at an abnormally rapid rate of at least 100 beats per minute with a QRS duration longer than 0.12 seconds. The wide QRS complex occurs because the electrical impulses are generated in the ventricles, leading to abnormal conduction pathways, which results in a slower, less organized depolarization of the ventricles compared to normal sinus conduction.

In other heart conditions such as normal sinus rhythm, atrial flutter, or sinus bradycardia, the QRS complexes typically remain narrow. Normal sinus rhythm reflects regular conduction with impulses traveling through the sinoatrial (SA) node and the atrioventricular (AV) node in an organized manner. Atrial flutter involves rapid atrial depolarization that typically does not affect the width of the QRS. Sinus bradycardia is characterized by a slow heart rate with regular QRS complexes that are also narrow. Thus, ventricular tachycardia is the clear context in which a wide QRS complex is encountered.