What does a prolonged QRS complex mean?
A widened QRS would, indeed, be consistent with V-tachy. Neither a-fib nor a block would lead to a wide complex or prolonged QRS complex. Of the three choices you mentioned, I’d have put wide complex, ventricular tachycardia as the focus of the pacemaker in the ventricle instead of the normal “electrical highway” hence the relatively slow, widened QRS complex. In advance cardiac life support it’s critical to identify whether a tachycardia is narrow or wide complex. A widened QRS is most commonly the result of a drug and doesn’t have to be in the setting of something horrific, but it’s when the focus of the pacing is below the AV node.
