This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S., Subject name: Medicine
A 70-year-old woman with known diabetes mellitus presenting with dyspnea, nausea and feeling of impending doom. ECG shows? 
Select and explain. 
A. Myocardial infarction, B. Unstable angina, C. Prinzmetal angina, D. Aortic dissection
A: Myocardial infarction
Answer: A: Myocardial infarction 
Explanation: Ans. (a) Myocardial infarction.* This tracing reveals sinus tachycardia at a rate of 100 beats/ min. The axis is normal.* Complete right bundle branch block is present, with a qR complex in VI and broad terminal S wave in V6 and lead I. There are pathologic Q waves in the septal leads of V1 and V2 with ST-segment elevation in leads V1 through V4.In this tracing, however, note the pathologic Q waves, ST elevation, and upright T waves in the anteroseptal leads. Conclusion is anterior ST elevation myocardial infarction in the setting of preexisting RBBB.