A 25-year-old white woman with no past medical history presents to the emergency department for “a racing heartbeat.” It is determined that she has paroxysmal supraventricular tachycardia. Which of the following is the drug of choice used for diagnosing and abolishing atrioventricular nodal arrhythmias by virtue of its effectiveness and its low toxicity?
The correct answer is D. Adenosine is extremely useful in abolishing atrioventricular (AV) nodal arrhythmias when given in highdose intravenous boluses. Adenosine works by hyperpolarizing AV node tissue by increasing the conductance of potassium and by reducing calcium current. As a result, the conduction through the AV node is markedly reduced. In addition to this, adenosine’s extremely short duration of action (15 seconds) limits the occurrence of its toxicities (i.e., hypotension, flushing, chest pain, and dyspnea).