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
30-60deg left axis detion- 
Select and explain. 
A. Left ventricular hyperophy, B. Right ventricular hyperophy, C. Aoic stenosis, D. Left atrial enlargement
A: Left ventricular hyperophy
Answer: A: Left ventricular hyperophy 
Explanation: High QRS voltage is the hallmark of left ventricular hyperophy(LVH), although many young patients have high QRS voltage without real LVH. Other associated hints (albeit nonspecific) are left axis detion, left atrial enlargement, widening of the QRS, and strain (associated ST-T abnormalities Ref Harrison 20th edition pg 1435