Mori J. Krantz, MD

For 2 days, a 49-year-old man with hypertension and hypercholesterolemiahas experienced light-headedness and fatigue.Based on the presenting ECG, what is the most likely cause of hissymptoms?A. Accelerated junctional rhythm.B. First-degree atrioventricular (AV) block.C. Mobitz type I (Wenckebach) second-degree AV block.D. Mobitz type II second-degree AV block.E. Third-degree AV block (complete heart block).

A 43-year-old woman presents with a 1-week history of fatigue and weakness.She has also experienced vague abdominal discomfort and constipation for thepast month. She has no history of cardiac disorders.Which of the following metabolic disturbances does the ECG implicateas the most likely cause of the patient's symptoms?

A 23-year-old woman has had 2 episodesof syncope during the past month.Her mother witnessed 1 episode inwhich the patient collapsed and lostconsciousness for a few minutes. Sheexperienced tonic-clonic seizure activitybut no subsequent confusion.

A 51-year-old man with hypertension, type 2 diabetes mellitus, and hypercholesterolemiapresents with a 1-hour history of substernal chest discomfort anddyspnea. He was given sublingual nitroglycerin in the emergency department,but his symptoms did not resolve.

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.