A 70-year-old man presents to his primary care physician for a general checkup. He states that he has been doing well and taking his medications as prescribed. He recently started a new diet and supplement to improve his health and has started exercising. The patient has a past medical history of diabetes, a myocardial infarction, and hypertension. He denies any shortness of breath at rest or with exertion. An ECG is performed and is within normal limits. Laboratory values are ordered as seen below. Serum: Na+: 139 mEq/L Cl-: 100 mEq/L K+: 6.7 mEq/L HCO3-: 25 mEq/L Glucose: 133 mg/dL Ca2+: 10.2 mg/dL Which of the following is the most likely cause of this patient's presentation?
AMedication
BAcute renal failure
CHemolysis
DDietary changes
ERhabdomyolysis
A 67-year-old man comes to the emergency department because of retrosternal chest pressure and shortness of breath for 4 hours. The symptoms started while he was walking to work and have only minimally improved with rest. He has a history of type 2 diabetes mellitus. He has smoked one pack of cigarettes daily for 35 years. He appears uncomfortable. His pulse is 95/min. Serum studies show a normal troponin concentration. An ECG shows no abnormalities. Which of the following is the most likely underlying cause of this patient's symptoms?
AAtherosclerotic plaque thrombus with complete coronary artery occlusion
BStable atherosclerotic plaque with 85% coronary artery occlusion
CAortic valve thickening and calcification
DDisruption of an atherosclerotic plaque with a non-occlusive coronary artery thrombus
ECoronary artery occlusion due to transient increase in vascular tone
A cardiologist is studying how a new virus that infects the heart affects the electrical conduction system of the cardiac myocytes. He decides to obtain electrocardiograms on patients with this disease in order to see how the wave patterns and durations change over time. While studying these records, he asks a medical student who is working with him to interpret the traces. Specifically, he asks her to identify the part that represents initial ventricular depolarization. Which of the following characteristics is most consistent with this feature of the electrocardiogram?
AElevated in patients with full thickness ischemic injury of the heart
BBecomes peaked in states of hyperkalemia
CBecomes prominent in states of hypokalemia
DNormal duration defined as less than 120 milliseconds
ENormal duration defined as less than 200 milliseconds
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