A 24-year-old woman comes to the office due to pressure-like, substernal chest pain that occurs when she exercises. The patient began noticing the pain approximately 6 months ago when she started to exercise to lose weight. Prior to that, her lifestyle was largely sedentary. She has no associated nausea, vomiting, diaphoresis, dyspnea, palpitations, or syncope. The patient has no significant past medical history but was told as a child that she has a "murmur." She has no significant family history of heart disease. Blood pressure is 130/70 mm Hg on the right and 105/55 mm Hg on the left, and pulse is 72/min and regular. BMI is 29 kg/m². A palpable thrill is present in the suprasternal notch. There is a loud midsystolic murmur best heard at the first right intercostal space. The lungs are clear to auscultation. What is the most likely cause of this patient's chest pain?

Question

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Supravalvular aortic stenosis (AS), the second most common type of AS, usually refers to congenital left ventricular outflow tract obstruction due to discrete or diffuse narrowing of the ascending aorta. This causes a systolic murmur similar to that seen with valvular AS; however, the murmur is usually best heard at the first right intercostal space, higher than where the valvular AS murmur is best heard. Patients may also have unequal carotid pulses, differential blood pressure in the upper extremities (high-pressure jet in ascending aorta), and a palpable thrill in the suprasternal notch. Patients with significant supravalvular AS develop left ventricular hypertrophy over time and can also have coronary artery stenosis as an associated anomaly. These changes, along with the increase in myocardial oxygen demand during exercise, can lead to subendocardial or myocardial ischemia, which is likely responsible for this patient's anginal symptoms during exercise. (Choice A) An anomalous right coronary artery that courses between the aortic root and the main pulmonary trunk can become compressed during exercise, leading to anginal symptoms. However, no associated murmurs or palpable thrill would be expected. (Choice B) Atherosclerotic coronary artery disease is unlikely in this patient given her young age and lack of cardiovascular risk factors other than obesity. (Choice D) Stretching of the papillary muscles can lead to mitral regurgitation, which causes a holosystolic or mid to late systolic murmur best heard at the cardiac apex. Exertional angina is not typically seen. (Choice E) Systolic anterior motion of the mitral valve is seen in patients with hypertrophic obstructive cardiomyopathy (HOCM). Patients with HOCM can have exertional angina, dyspnea, dizziness, presyncope, or syncope. However, the systolic murmur of HOCM has maximal intensity along the lower left sternal border and typically changes in intensity with various physiologic maneuvers. Educational objective: Patients with aortic outflow obstruction from supravalvular aortic stenosis develop left ventricular hypertrophy and can have exertional angina due to subendocardial ischemia with increased myocardial oxygen demand during exercise. References: Pathology of coronary arteries, myocardium, and great arteries in supravalvular aortic stenosis. Report of five cases with implications for surgical treatment. (http://www.ncbi.nlm.nih.gov/pubmed/8028375)

A 24-Year-Old Woman Comes to the Office Due to Pressure-Like