Snapshot A 24-year-old woman presents with tachycardia. She reports that this happens every few years without any identifiable causes. Her pulse is 200/min. Her other vital signs are stable. An electrocardiogram shows a patient with narrow complex QRS, tachycardia to 204/min, and a regular rhythm. She is given a medication to slow down the atrioventricular node and attempt to end the narrow complex tachycardia. (Adenosine) Introduction Adenosine login to view 6 more bullets Calcium channel blockers login to view 8 more bullets Digoxin login to view 8 more bullets β-blockers login to view 4 more bullets