Final answer:
The symptoms listed—sudden severe chest pain radiating to the back, hypertension, and decrescendo diastolic murmur—most likely indicate an aortic dissection rather than acute myocardial infarction, pericarditis, or pulmonary embolism.
Step-by-step explanation:
The symptoms described in the question, particularly the sudden severe chest pain radiating to the back, hypertension, and decrescendo diastolic murmur, point towards aortic dissection as the most likely diagnosis. In acute myocardial infarction (MI), pain is typically beneath the sternum (retrosternal pain), radiating down the left arm, especially in males, and is associated with symptoms like difficulty breathing, nausea, and sweating.
Moreover, angina is a chest pain or discomfort often related to inadequate blood flow to the heart, and can also share some symptoms with MI. However, the radiating pain to the back and the decrescendo diastolic murmur are more characteristic of aortic dissection rather than MI, pericarditis, or pulmonary embolism.