A 62-year-old man with a long history of hypertension comes to the clinic for a routine physical examination. Blood pressure is 150/90 mm Hg and pulse is 74/min and regular. Cardiac auscultation reveals a low-frequency, presystolic sound that immediately precedes S1 and is best heard during expiration when the patient is lying on his left side. Chest x-ray reveals extensive calcification around the mitral and aortic valves. Which of the following is the most likely explanation for the additional heart sound?

Question

A 62-year-old man with a long history of hypertension comes to the clinic for a routine physical examination.  Blood pressure is 150/90 mm Hg and pulse is 74/min and regular.  Cardiac auscultation reveals a low-frequency, presystolic sound that immediately precedes S1 and is best heard during expiration when the patient is lying on his left side.  Chest x-ray reveals extensive calcification around the mitral and aortic valves.  Which of the following is the most likely explanation for the additional heart sound?

Quizplus · Accepted Answer

11ec160b_3a8a_d12e_9249_db79a25c799d_MD0001_00 This patient has an S4 (low-frequency sound occurring just before S1), which is most likely secondary to concentric left ventricular hypertrophy (LVH) from longstanding hypertension (hypertensive heart disease). The calcifications revealed on chest x-ray likely represent degenerative mitral and aortic valve calcification, which is age related and typically accelerated by systemic hypertension. An S4 is a sign of diastolic dysfunction. It occurs due to blood striking a stiffened ventricular wall during atrial contraction at the end of diastole. An S4 may be present in any condition that causes reduced ventricular compliance (eg, hypertensive heart disease, restrictive cardiomyopathy, acute myocardial infarction). A left-sided S4 is best heard with the bell of the stethoscope over the cardiac apex with the patient in the left lateral decubitus position; it will intensify during expiration due to increased blood flow from the lungs to the left atrium. (Choices A and D) Age-related aortic valve calcification can cause restricted motion of the aortic valve cusps and lead to aortic stenosis. There may be a high-frequency ejection click heard just after S1, followed by the crescendo-decrescendo systolic murmur of aortic stenosis created by increased flow velocity through the aortic valve (and best heard at the right upper sternal border). Aortic stenosis is also a potential cause of concentric LVH and an S4, but it is a less common cause than chronic hypertension. (Choice C) An S3 is caused by blood filling an enlarged (or overfull) ventricular cavity during early passive diastolic filling. It occurs shortly after S2 and is often heard in patients with heart failure with reduced ejection fraction or other causes of ventricular volume overload (eg, mitral or aortic regurgitation). (Choice E) Systolic anterior motion of the mitral valve can exacerbate left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy (HCM). HCM is expected to cause a systolic ejection murmur best heard at the left sternal border. An S4 is also sometimes heard with HCM. Educational objective: An S4 is a low-frequency, late diastolic sound that immediately precedes S1. It is caused by blood striking a stiffened ventricular wall during atrial contraction; concentric left ventricular hypertrophy due to chronic hypertension (or less commonly due to aortic stenosis) is a common cause of an S4.

A 62-Year-Old Man with a Long History of Hypertension Comes