A Forty-Year-Old Man Reported to His Cardiologist That He Had

A forty-year-old man reported to his cardiologist that he had unusual feelings in his chest after drinking his fourth cup of coffee in the morning. The cardiologist recorded the following electrocardiogram during an exercise stress test. Leads II and III are shown. What is the likely diagnosis?

A) Premature contraction originating in the atrium
B) Premature contraction originating high in the atrioventricular node
C) Premature contraction originating low in the atrioventricular node
D) Premature contraction originating in the apex of the ventricle
E) Premature contraction originating in the base of the ventricle