cardiology2016 91-100

r:B This patient has a fourth heart sound (S4) that is most likely caused by extensive left ventricular hypertrophy due to long-standing hypertension (hypertensive heart disease). The calcifications seen on chest x-ray likely represent degenerative mitral annular and aortic valve calcifications, which are also associated with systemic hypertension. The S4 heart sound is a sign of diastolic dysfunction. It occurs when there is a sudden rise in end-diastolic ventricular pressure caused by atrial contraction against a ventricle that has reached its elastic limit. An S4 may be present in any condition that causes reduced ventricular compliance (eg, hypertensive heart disease, aortic stenosis, hypertrophic cardiomyopathy). It is heard as a low-frequency late diastolic sound that occurs just prior to the first heart sound (S1) after the onset of the P wave on ECG (coinciding with the active phase of ventricular filling). A leftsided 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. (Choice A) Increased flow velocity through the aortic valve would produce a crescendo-decrescendo ejection murmur during systole (after S1 and before S2), similar to the murmur of aortic stenosis. (Choice C) Rapid passive filling of the ventricles leads to a diastolic third heart sound (S3) that is heard shortly after S2. It is often heard in patients with an enlarged ventricular chamber (dilated cardiomyopathy) and in high cardiac output states (pregnancy, thyrotoxicosis). (Choice D) Restricted motion of the aortic valve cusps can be associated with an aortic ejection click, aortic stenosis, and/or aortic regurgitation. The aortic ejection click and the ejection systolic murmur of aortic stenosis occur in early systole after S1, whereas the diastolic murmur of aortic regurgitation begins immediately after S2. (Choice E) Systolic anterior motion (SAM) of the mitral valve occurs in patients with hypertrophic cardiomyopathy and can cause eccentric mitral regurgitation and exacerbation of left ventricular outflow tract obstruction. However, these would result in systolic murmurs (after S1 and before S2). Educational objective: A diastolic sound on cardiac auscultation that immediately precedes S1 is most often a fourth heart sound (S4). An abnormal S4 can be heard in patients with reduced ventricular compliance (eg, hypertensive heart disease, aortic stenosis, hypertrophic cardiomyopathy). It is caused by a sudden rise in end-diastolic pressure following atrial contraction.
Q2
A 62-year-old man with a long history of hypertension comes to the physician for a routine physical examination. His blood pressure is 150/90 mm Hg and heart rate is 74/min and regular. Cardiac auscultation shows a presystolic sound that immediately precedes the first heart sound 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? A. Increased flow velocity through the aortic valve B. Increased stiffness of the left ventricular wall C. Rapid passive filling of the ventricles D. Restricted motion of the aortic valve cusps E. Systolic anterior motion of the mitral valve
cardiology2016 91-100
A 65-year-old man comes to the office due to exertional dyspnea and easy fatigability. He has no other medical problems. The patient has not seen a physician in the last 10 years. He takes no medications but smokes a pack of cigarettes per day and drinks approximately 7-10 alcoholic beverages a week His blood pressure is 170/90 mm Hg and pulse is 80/min. Physical examination reveals bilateral lung crackles. Which of the following sets of diagnostic findings would be most consistent with isolated diastolic heart failure?
Q1
Correct answer:E Diastolic heart failure (DHF) is a common cause of acute decompensated HF. It is characterized by normal or nearnormal left ventricular ejection fraction (LVEF, >50%) and end-diastolic volume in the setting of increased LV filling pressures Diastolic dysfunction can be due to conditions that decrease LV compliance, such as impaired myocardial relaxation (eg. from ischemia) or increased intrinsic ventricular wall stiffness (eg, from amyloid deposition). This patient most likely has long-standing hypertension leading to LV wall hypertrophy, which can impair myocardial relaxation and increase intrinsic wall stiffness LV diastolic pressure is determined by the blood volume in the LV cavity and compliance of the left ventricle. Conditions that reduce ventricular compliance lead to increased LV end-diastolic pressures (LVEDP) at the same LVED volumes. This causes a shift in the pressure-volume curve that goes upward and to the left (point a - b). As diastolic dysfunction worsens, LVEDP continues to rise as the heart attempts to maintain a near-normal stroke volume and cardiac output. Decompensation occurs when the increased LVEDP (transmitted to the left atrium and pulmonary veins) causes pulmonary edema and dyspnea. Cardiac reserve also diminishes as the stiffened ventricle becomes less effective at accommodating increased blood volumes (limiting the ability to use the Frank-Stariing mechanism). (Choice A) In contrast to diastolic HF. systolic HF is caused by a primary decrease in myocardial contractility rather than ventricular compliance. As a result, systolic HF is characterized by a reduced LVEF (<50%), along with progressive chamber dilation with increased LV volume and elevated LVEDP. (Choices B, C, and F) LVEDP is elevated (not normal) in patients with diastolic HF. This increase in LVEDP is transmitted to the left atrium, pulmonary veins, and capillaries; the result is pulmonary congestion, dyspnea, and exercise intolerance. Educational objective: