A 35-year-old primigravid woman comes to the clinic during the second trimester. The patient reports that she has had some tiredness, which she attributes to pregnancy. She takes 1 nap during the day. She has no chest pain, cough, or lower extremity swelling. As a child, the patient was told that she has a murmur but does not know any details and says that she has felt well until recently. On physical examination, a 3/6 midsystolic murmur is heard at the left upper sternal border and S2 is widely split. Which of the following is the most likely diagnosis?

Question

A 35-year-old primigravid woman comes to the clinic during the second trimester.  The patient reports that she has had some tiredness, which she attributes to pregnancy.  She takes 1 nap during the day.  She has no chest pain, cough, or lower extremity swelling.  As a child, the patient was told that she has a murmur but does not know any details and says that she has felt well until recently.  On physical examination, a 3/6 midsystolic murmur is heard at the left upper sternal border and S2 is widely split.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec160b_38e6_48b8_9249_3f1b4d22939b_MD0001_00 This patient likely has pulmonic valve stenosis (PS), which most commonly occurs as an isolated congenital defect and rarely occurs as an acquired defect (eg, rheumatic fever, carcinoid syndrome). Severe PS is typically diagnosed early in life due to development of right-sided heart failure, but patients with relatively mild PS often do not present with symptoms (eg, dyspnea, fatigue) until adulthood. The physiologic changes of pregnancy (eg, increased plasma volume) can unmask underlying PS. Cardiac auscultation in PS reveals a pulmonic ejection click followed by a harsh crescendo-decrescendo systolic murmur best heard at the left upper sternal border. The stenosis causes the pulmonic valve to close later than usual as it takes longer for the right ventricle to push blood through the narrowed valve. This results in widened splitting of the aortic and pulmonic components of S2. Inspiration draws additional blood into the right side of heart, which increases the intensity of the murmur and further widens the splitting of S2. Pulmonary hypertension is another cause of widened splitting of S2 because more time is required for the right ventricle to overcome pulmonary arterial pressure (ie, the pulmonic valve opens later and closes later). (Choice A) A benign flow murmur can occur in patients with high cardiac output states (eg, pregnancy) due to increased flow across the aortic and pulmonic valves; however, the murmur is typically low grade (2/6 or less) and abnormal splitting of S2 is not present. (Choice B) A bicuspid aortic valve is the most common congenital heart defect seen in adults and can lead to aortic stenosis in relatively young patients (eg, those in their 50s). However, aortic stenosis causes delayed closure of the aortic valve, leading to narrowed or paradoxical splitting of S2. (Choice C) Hypertrophic cardiomyopathy can cause a systolic murmur that mimics that of aortic stenosis and is best heard at the mid-left sternal border. Aortic valve closure may be delayed due to prolonged ejection of blood through the left ventricular outflow tract. (Choice E) A small- or moderate-sized ventricular septal defect may present in adulthood with symptoms of heart failure. There is typically widened splitting of S2 due to early closure of the aortic valve (less blood is ejected into the aorta because some blood is ejected into the right ventricle). However, a holosystolic murmur best heard at the left lower sternal border is expected. Educational objective: Pulmonic valve stenosis causes a crescendo-decrescendo systolic murmur (best heard at the left upper sternal border) and delays closure of the pulmonic valve, resulting in widened splitting of S2. Inspiration increases blood flow to the right side of the heart, causing increased intensity of the murmur and even later closure of the pulmonic valve.

A 35-Year-Old Primigravid Woman Comes to the Clinic During the Second