system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 2-year-old boy is brought to the physician by his father for a well-child examination. He recently emigrated from Mexico with his family and has not seen a physician since birth. Vital signs are within normal limits. Cardiac examination shows a harsh, grade 3/6 holosystolic murmur heard best at the left lower sternal border. During deep inspiration, the second heart sound is split. If left untreated, irreversible changes would most likely be seen in which of the following structures?
assistant
Pulmonary artery