William A. Baker, MD

A 3-day history of intermittent fainting spells brings a 49-year-old man to youroffice. His only significant medical history includes seasonal allergic rhinitis,for which he takes terfenadine, and mild depression, which is being treatedwith amitriptyline. A week ago, he began taking erythromycin, 500 mg qid,for acute pharyngitis.

Cardiac stress imaging has become increasingly sophisticated; nevertheless, standard exercise electrocardiography can provide valuable clinical information, such as time to onset of angina or ST-segment depression, maximal heart rate and blood pressure response, and total exercise duration. Pharmacologic stress agents may be substituted for patients who cannot exercise on a treadmill; however, these agents must be used in conjunction with echocardiography or nuclear scintigraphy to obtain adequate diagnostic information.

A 41-year-old woman has had a 2-week bout of nausea, vomiting, and diarrhea.Her history includes chronic hepatitis C and alcohol abuse. She also has orthostatichypotension. A baseline ECG is obtained.