This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: ECG and Arrhythmia 2, Subject name: Medicine
[{'content': 'A 70-year old hypeensive patient with a complaint of palpitations and pre-syncope. On examination, his hea rate is 72 BPM and BP was 150/100. ECG performed shows? \nSelect and explain. \nA. Atrial flutter, B. Atrial fibrillation, C. Multifocal atrial tachycardia, D. PSVT', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ECG in lead II and other inferior leads shows the presence of flutter waves( Saw tooth pattern). 3-4 flutter waves before every narrow QRS complex. Since the ventricular rate is 75 bpm (RR interval), atrial rate shall be obtained by multiplying the ventricular rate by 4 which is 300 bpm The presence of risk factor of hypeension also give clue to diagnosis of atrial flutter.', 'role': 'assistant'}]