What is the most likely diagnosis for a young patient with intermittent chest pain and a specific systolic murmur heard best over the apex?

The presence of intermittent chest pain combined with a specific systolic murmur best heard over the apex strongly suggests mitral valve prolapse. This condition is characterized by the displacement of one or both of the mitral valve leaflets into the left atrium during systole, which can lead to a characteristic mid-systolic click followed by a regurgitant murmur.

In many young patients, mitral valve prolapse is a common finding and can be associated with chest discomfort, often due to the anxiety or palpitations related to the condition. The murmur associated with mitral valve prolapse is typically described as a “whooshing” sound that reflects the backflow of blood into the left atrium during systole, making it distinct and identifiable.

In contrast, aortic regurgitation typically presents with a diastolic murmur that is best heard along the left sternal border, which differs from the findings in this case. Mitral stenosis would produce a diastolic murmur rather than a systolic one, as it involves obstruction of blood flow from the left atrium to the left ventricle during diastole. Pericarditis usually presents with a sharp, pleuritic chest pain and a scratch