A 63-year-old man comes to the physician for a routine health maintenance examination. He feels well. He has a history of hypertension, atrial fibrillation, bipolar disorder, and osteoarthritis of the knees. Current medications include lisinopril, amiodarone, lamotrigine, and acetaminophen. He started amiodarone 6 months ago and switched from lithium to lamotrigine 4 months ago. The patient does not smoke. He drinks 1–4 beers per week. He does not use illicit drugs. Vital signs are within normal limits. Examination shows no abnormalities. Laboratory studies show: Serum Na+ 137 mEq/L K+ 4.2 mEq/L Cl- 105 mEq/L HCO3- 24 mEq/L Urea nitrogen 14 mg/dL Creatinine 0.9 mg/dL Alkaline phosphatase 82 U/L Aspartate aminotransferase (AST) 110 U/L Alanine aminotransferase (ALT) 115 U/L Which of the following is the most appropriate next step in management?
ADiscontinue amiodarone
BDiscontinue acetaminophen
CFollow-up laboratory results in 3 months
DFollow-up laboratory results in 6 months
EDecrease alcohol consumption
A 70-year-old male immigrant from Asia is brought to the emergency room with complaints of palpitations and light-headedness for 1 hour. The patient was sitting in his chair watching television when he felt his heart racing and became dizzy. He was unable to stand up from his chair because of weakness and light-headedness. His past medical history is notable for mitral stenosis secondary to rheumatic fever as a child. On arrival to the emergency department, the patient's temperature is 99.7°F (37.6°C), blood pressure is 110/55 mmHg, pulse is 140/min, and respirations are 15/min. The patient appears comfortable but anxious. Electrocardiogram shows atrial fibrillation with rapid ventricular response. The patient is started on dofetilide. Which of the following would be expected in this patient’s cardiac action potential as a result of this drug?
ADecreased conduction velocity
BIncreased QT interval
CDecreased calcium current
DDecreased slope of phase 0
EDecreased slope of phase 4
A 53-year-old man with obesity and heart disease presents to your outpatient clinic with complaints of orthopnea, significant dyspnea on minimal exertion, nausea, vomiting, and diarrhea. He says that his old doctor gave him "some pills" that he takes in varying amounts every morning. Physical exam is significant for a severely displaced point of maximal impulse, bilateral rales in the lower lung fields, an S3 gallop, and hepatomegaly. You decide to perform an EKG (shown in figure A). Suddenly, his rhythm changes to ventricular tachycardia followed by ventricular fibrillation, and he syncopizes and expires despite resuscitative efforts. High levels of which medication are most likely responsible?
APropranolol
BAmiodarone
CLidocaine
DVerapamil
EDigoxin
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