A 45-Year-Old Man Who Was Recently Started on Medication for Paroxysmal

question 429

Multiple Choice

A 45-year-old man who was recently started on medication for paroxysmal atrial fibrillation undergoes stress ECG testing.  The patient exercises on a treadmill for 9 minutes and reaches 98% of age-predicted maximal heart rate without chest pain or ST-segment changes.  His pre-test resting QRS complex duration is 95 msec (normal: 80-120 msec) and corrected QT (QTc) interval duration is 410 msec (normal <440 msec) .  ECG findings recorded at his maximally achieved heart rate show a QRS complex duration of 125 msec and QTc interval duration of 400 msec.  Based on the patient's test results, which of the following medications is most likely being used to treat his atrial fibrillation?

• A)Atenolol
• B)Digoxin
• C)Dofetilide
• D)Flecainide
• E)Verapamil

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