In a patient with Pectus Excavatum associated with Marfan syndrome, which heart murmur is most likely present?

In patients with Marfan syndrome, aortic regurgitation is commonly observed due to the structural changes in the aorta. Marfan syndrome is associated with abnormalities in connective tissue, leading to weakened aortic walls and elastic fibers. This can result in aortic dilation and eventually lead to aortic regurgitation.

In the presence of pectus excavatum, which is a depression in the chest wall that can affect thoracic organ positioning, the potential for cardiovascular anomalies increases. When the aorta becomes dilated in Marfan syndrome, the valve can become insufficient, causing blood to flow back into the left ventricle during diastole, which is what characterizes aortic regurgitation.

The murmur associated with aortic regurgitation typically occurs during diastole and is best heard along the left sternal border, making it distinct within the context of other possible murmurs. The structural vulnerability of the aorta in Marfan syndrome, combined with the physiological implications of pectus excavatum, establishes a strong correlation with the presence of aortic regurgitation.