A 32-year-old man comes to the office due to occasional palpitations. The patient's medical history is unremarkable, and he considers himself healthy. His maternal uncle died suddenly at age 40, and a cousin underwent heart surgery at a young age. The examiner asks the patient to sit upright, lean forward, and hold his breath in full expiration as the stethoscope diaphragm is placed at the left sternal border and firm pressure is applied. There is a decrescendo early diastolic murmur. The rest of the physical examination is unremarkable. Which of the following is the most likely diagnosis in this patient?

Question

A 32-year-old man comes to the office due to occasional palpitations.  The patient's medical history is unremarkable, and he considers himself healthy.  His maternal uncle died suddenly at age 40, and a cousin underwent heart surgery at a young age.  The examiner asks the patient to sit upright, lean forward, and hold his breath in full expiration as the stethoscope diaphragm is placed at the left sternal border and firm pressure is applied.  There is a decrescendo early diastolic murmur.  The rest of the physical examination is unremarkable.  Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

11ec25c8_d330_2fb5_bc81_c9d6a9a7af0d_MD0003_00 This patient's presentation is consistent with valvular aortic regurgitation (AR) due to a bicuspid aortic valve (BAV). BAV is a common type of congenital heart disease. Some cases develop sporadically, whereas others have a mendelian inheritance pattern (eg, autosomal dominant with incomplete penetrance), likely explaining this patient's family history. Although frequently associated with aortic stenosis (AS), BAV is also the most common cause of AR in developed countries. Patients with AR due to BAV are typically diagnosed in their 30s or 40s, an age ~10 years lower than that at which AS due to BAV presents. The AR can be asymptomatic or cause palpitations, chest pain, or dyspnea. It is usually valvular in nature, presenting as a decrescendo, early diastolic murmur, best heard at the left sternal border with the patient leaning forward (heart brought forward in the chest wall) and holding a deep breath in expiration (murmur easier to hear). decrescendo left sternal border BAV is sometimes associated with aortic root dilation, which can also cause AR. With AR due to root dilation, the murmur is best heard at the right upper sternal border, reflecting the turbulent flow around the aortic root. Aortic root dilation can progress to aortic aneurysm and dissection, sometimes causing sudden death. (Choice A) Atrial septal defect (ASD) usually presents with wide and fixed splitting of S2. A systolic murmur can be heard over the left second intercostal space (increased flow across the pulmonic valve). A large ASD with significant left-to-right shunting can cause a middiastolic murmur (increased flow across the tricuspid valve). (Choice C) Although associated with a positive family history (eg, sudden cardiac death), hypertrophic cardiomyopathy typically presents with a harsh crescendo-decrescendo systolic murmur that is best heard at the left sternal border and that increases with maneuvers that decrease left ventricular volume (eg, Valsalva) and decreases with maneuvers that increase left ventricular volume (eg, squatting). (Choice D) Infective endocarditis can cause AR but is much less likely than BAV in a healthy patient with a family history of cardiac conditions and only intermittent palpitations (but no fevers or chills). (Choice E) Rheumatic heart disease only rarely causes isolated aortic valve involvement; there is almost always concomitant mitral valve disease, usually from mitral stenosis (eg, opening snap, middiastolic murmur). Educational objective: Congenital bicuspid aortic valve is the most common cause of aortic regurgitation (AR) in developed countries, with patients typically diagnosed in their 30s or 40s. The AR is usually valvular but can also be due to aortic root dilation. References: Valvular heart disease: aortic regurgitation. (http://www.ncbi.nlm.nih.gov/pubmed/15998697)

A 32-Year-Old Man Comes to the Office Due to Occasional