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: Pediatrics
[{'content': 'The presence of left axis detion beyond -30deg in electrocardiogram suggests \nSelect and explain. \nA. Fossa ovalis ASD, B. Sinus venosus ASD, C. Ostium primum ASD, D. Coronary sinus ASD', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The electrocardiogram of ostium secundum ASD is characterized by right axis detion and right ventricular hyperophy. The characteristic configuration of the lead Vl is rsR&; seen in almost 90% patients. Presence of left axis detion beyond -30deg suggests ostium primum ASD. Reference: Essential Paediatrics; O.P. Ghai; Page no: 413', 'role': 'assistant'}]