Final answer:
The most likely diagnosis for a patient with tearing chest pain radiating to the back is an aortic dissection, a severe condition characterized by a tear in the aorta's inner layer.
Step-by-step explanation:
A patient presenting to the ER with tearing chest pain radiating to the back could be experiencing a number of conditions, but one of the most concerning and emergent diagnoses to consider is an aortic dissection. This condition involves a tear in the inner layer of the aorta, causing severe and sudden chest pain. While acute myocardial infarction (MI) can also present with chest pain, the pain from an MI typically manifests as retrosternal discomfort, often radiating down the left arm especially in males, and may be associated with symptoms like difficulty breathing, palpitations, nausea, sweating, and anxiety. However, the tearing nature of the pain radiating to the back is more characteristic of an aortic dissection, a life-threatening condition that requires immediate attention.