A 32-year-old woman comes to the office due to progressive exertional dyspnea and easy fatigability. She immigrated to the United States from India several years ago and reports a history of rheumatic fever during her childhood. Cardiac auscultation reveals a diastolic high-frequency sound and a rumbling diastolic murmur heard best in the left fifth intercostal space at the midclavicular line. Cardiac catheterization is performed for hemodynamic evaluation, and the results are represented below. Timing of the high-frequency sound heard during cardiac auscultation of this patient best corresponds to which of the following letters?

Question

A 32-year-old woman comes to the office due to progressive exertional dyspnea and easy fatigability.  She immigrated to the United States from India several years ago and reports a history of rheumatic fever during her childhood.  Cardiac auscultation reveals a diastolic high-frequency sound and a rumbling diastolic murmur heard best in the left fifth intercostal space at the midclavicular line.  Cardiac catheterization is performed for hemodynamic evaluation, and the results are represented below.  Timing of the high-frequency sound heard during cardiac auscultation of this patient best corresponds to which of the following letters?

Quizplus · Accepted Answer

11ec160b_3a94_9545_9249_fb2902f2b1b0_MD0001_00 This patient with a history of rheumatic fever now presenting with exertional dyspnea and a diastolic murmur at the cardiac apex most likely has mitral stenosis. In comparison to normal tracings, hemodynamic tracings in patients with mitral stenosis typically reveal an elevated pressure gradient between the left atrial and left ventricular end-diastolic pressure. Classic physical examination findings include a loud first heart sound (S1), an early diastolic high-frequency opening snap after the second heart sound (S2), and a low-pitched diastolic rumble. These findings are best heard at the cardiac apex using the bell of the stethoscope with the patient lying on the left side in held expiration. Left ventricular pressure falls rapidly during isovolumetric relaxation. The opening snap is caused by the sudden opening of the mitral valve leaflets when the left ventricular diastolic pressure falls below the left atrial pressure at the beginning of diastole. As mitral stenosis becomes more severe, the opening snap occurs earlier after S2. (Choice A) This point corresponds to the opening of the aortic valve at the end of isovolumetric ventricular contraction in early systole when the left ventricular pressure exceeds the central aortic pressure. This correlates with the timing of an aortic ejection murmur that may be heard in patients with aortic stenosis (eg, due to a calcified bicuspid aortic valve). (Choice B) This point corresponds to the closure of the aortic valve at the end of systole, producing the aortic component of S2. The aortic valve closes as soon as left ventricular pressure drops below the aortic pressure. (Choice D) This is a random point in diastole when the mitral valve is already maximally open and there is passive filling of the left ventricular cavity (diastasis). In patients with mitral stenosis, the elevated pressure gradient between the left atrium and left ventricle during diastole causes the mid-diastolic rumble. (Choice E) This point roughly corresponds to the onset of atrial contraction during late ventricular diastole. In patients in sinus rhythm, atrial contraction causes an increase in the intensity of the diastolic murmur just before S1, a phenomenon termed "presystolic accentuation." Educational objective: Cardiac auscultation in patients with mitral stenosis reveals a loud first heart sound, an early diastolic opening snap after the second heart sound, and a low-pitched diastolic rumble best heard at the cardiac apex. The opening snap is caused by the sudden opening of the mitral valve leaflets when the left ventricular pressure falls below the left atrial pressure at the beginning of diastole. __________ References: Mitral stenosis. (http://www.ncbi.nlm.nih.gov/pubmed/19747723)

A 32-Year-Old Woman Comes to the Office Due to Progressive