A 35-year-old woman comes to the office for a follow-up appointment after recent hospitalization. The patient presented to the emergency department with fever and malaise and was diagnosed with infective endocarditis. She underwent a prolonged course of antibiotic therapy and her last dose was 5 days ago. She has no fever or shortness of breath and has resumed her daily activities. The patient has no other medical problems. Blood pressure is 128/72 mm Hg and pulse is 78/min. Auscultatory findings recorded at the left sternal border are shown in the phonocardiogram below. Which of the following is the most likely cause of the murmur depicted above?

Question

A 35-year-old woman comes to the office for a follow-up appointment after recent hospitalization.  The patient presented to the emergency department with fever and malaise and was diagnosed with infective endocarditis.  She underwent a prolonged course of antibiotic therapy and her last dose was 5 days ago.  She has no fever or shortness of breath and has resumed her daily activities.  The patient has no other medical problems.  Blood pressure is 128/72 mm Hg and pulse is 78/min.  Auscultatory findings recorded at the left sternal border are shown in the phonocardiogram below.  Which of the following is the most likely cause of the murmur depicted above?

Quizplus · Accepted Answer

11ec160b_3ca6_855f_9249_79747895fca7_MD0001_00 This patient's phonocardiogram shows a holosystolic murmur that increases in intensity during inspiration. Holosystolic murmurs are associated with tricuspid regurgitation (TR), mitral regurgitation (MR), and ventricular septal defects (VSDs). Intrathoracic pressure drops during inspiration, allowing more blood to return to the right heart. Right ventricular stroke volume rises due to increased venous return. However, the drop in intrathoracic pressure also increases pulmonary vessel capacity, leading to a transient decrease in left ventricular venous return. As a result, a TR murmur would be expected to increase in intensity during inspiration (Carvallo sign), whereas murmurs associated with MR or VSD would either decrease or not change. TR is further favored over MR as TR is loudest near the left sternal border at the second and third intercostal spaces. MR is heard most prominently over the cardiac apex. A VSD produces a holosystolic murmur that is typically loudest over the left sternal border in the third or fourth intercostal spaces. (Choice A) Aortic stenosis is characterized by a mid-systolic ejection murmur that starts after S1 and ends before S2 and is heard best at the right second interspace. This murmur has a crescendo-decrescendo (diamond-shaped) configuration. (Choice B) MR causes a high-pitched holosystolic murmur most prominent over the cardiac apex, which is best heard with the patient in the left lateral decubitus position. The murmur of MR displays little respiratory variation. (Choice C) Mitral stenosis is associated with an opening snap of the mitral valve and a low-pitched rumbling murmur heard throughout diastole. (Choice D) Pulmonic regurgitation yields an early diastolic murmur that starts with S2 and ends before S1. The murmur has a decrescendo configuration and may increase in intensity during inspiration. It has a high-pitched, blowing sound that is best heard over the left second and third intercostal spaces. Educational objective: A holosystolic murmur that increases in intensity on inspiration most likely represents tricuspid regurgitation. The other holosystolic murmurs (which are secondary to mitral regurgitation or a ventricular septal defect) do not typically increase in intensity during inspiration.

A 35-Year-Old Woman Comes to the Office for a Follow-Up