What is the most likely diagnosis for a newborn with absent breath sounds on the left and heart sounds shifted to the right?

The diagnosis of a diaphragmatic hernia is indicated by the presence of absent breath sounds on one side, coupled with a shift of heart sounds to the opposite side. In newborns, a diaphragmatic hernia occurs when there is an abnormal opening in the diaphragm, usually allowing abdominal organs, such as the stomach and intestines, to move into the thoracic cavity. This can compress the lung on the affected side, leading to decreased or absent breath sounds, as well as displacement of the mediastinum, which results in the heart sounds being shifted away from the site of the hernia.

In cases of congenital pneumothorax, breath sounds may typically be diminished or absent as well, but the heart sounds would not be significantly altered in the same manner. Transposition of the great vessels primarily involves cardiovascular abnormalities and would not typically present with absent breath sounds or a significant mediastinal shift. Pneumonia in a newborn would usually lead to decreased breath sounds and potentially an increase in respiratory distress, but it would not cause such a notable shift in heart sounds or absence of breath sounds on one side.

Thus, the presentation of absent breath sounds on the left side, along with a rightward shift of heart sounds, strongly aligns with