This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hea Sounds, Subject name: Medicine
[{'content': 'A 10-year old child with Valvular hea disease on hea failure treatment, has the following ECG tracing. What is the diagnosis? \nSelect and explain. \nA. Tall tented T wave, B. Ventricular bigeminy, C. Non paroxysmal atrial tachycardia with irregular AV block, D. Non paroxysmal atria tachycardia with regular AV block', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Hea rate of the patient is 50bpm . ECG tracing shows normal sinus rhythm alternating with premature ventricular contraction. This is diagnostic of ventricular bigeminy which is the most common arrhythmia seen with digoxin toxicity.', 'role': 'assistant'}]