You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Wide fixed split S2 occurs in and explain in detail?
Ref Harrison 19 th ed pg 1447 Fixed splitting of S2 , in which the A2 -P2 interval is wide and does not change during the respiratory cycle, occurs in patients with a secundum atrial septal defect.