Arrhythmic complications managementDownloads

A 39-year-old woman is brought to the emergency department 30 minutes after her husband found her unconscious on the living room floor. She does not report having experienced light-headedness, nausea, sweating, or visual disturbance before losing consciousness. Three weeks ago, she was diagnosed with open-angle glaucoma and began treatment with an antiglaucoma drug in the form of eye drops. She last used the eye drops 1 hour ago. Examination shows pupils of normal size that are reactive to light. An ECG shows sinus bradycardia. This patient is most likely undergoing treatment with which of the following drugs?

A 62-year-old man is brought to the emergency department because of syncope. He reports sudden onset of palpitations followed by loss of consciousness while carrying his groceries to his car. He is unable to recall any further details and does not have any chest pain or dizziness. He has a history of hypertension, type 2 diabetes mellitus, gastroparesis, and osteoarthritis of the knees. Medications include lisinopril, metformin, and ondansetron as needed for nausea. He also takes methadone daily for chronic pain. Apart from an abrasion on his forehead, he appears well. His temperature is 37.2 °C (98.9 F), heart rate is 104/min and regular, and blood pressure is 135/70 mm Hg. While he is in the emergency department, he loses consciousness again. Telemetry shows polymorphic ventricular tachycardia with cyclic alteration of the QRS axis that spontaneously resolves after 30 seconds. Results of a complete blood count, serum electrolyte concentrations, and serum thyroid studies show no abnormalities. Cardiac enzymes are within normal limits. Which of the following is the most likely underlying cause of this patient's syncope?