with normal sinus rhythm (NSR), who has had three premature ventricular contractions (PVCs) in the past hour.

recovering from cardiac catheterization and has had two brief runs of ventricular tachycardia (VT).

with atrial fibrillation, whose heart rate decreased from 113 to 95 beats per minute.

who has developed sinus tachycardia (ST) following the application of nitroglycerin paste.