Joel A. Garcia, 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 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.