A 65-year-old man with a long history of hypertension and type 2 diabetes mellitus comes to the office for a routine checkup. The patient is a former smoker with a 15-pack-year history. He jogs 3 miles per day. BMI is 28.5 kg/m². Family history is unremarkable. Auscultation findings over the cardiac apex are given below. The auscultation findings are best explained by which of the following?

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11ec160b_3a8c_a5f1_9249_4b43ce2aee90_MD0001_00 This patient has a low pitch, extra heart sound at the end of diastole (just before S1) known as an S4. An S4 is thought to be caused by blood striking a stiff ventricular wall during atrial contraction. It can be a normal finding in elderly patients (eg, age >70) due to a physiologic, age-related decrease in left ventricular (LV) compliance. However, in younger patients it typically indicates pathologic LV wall stiffening, most commonly due to concentric LV hypertrophy in response to prolonged hypertension (likely the cause in this case). In comparison, an S3 is heard in early diastole (just after S2) and is thought to result from reverberation of sound due to blood filling an enlarged and volume-overloaded ventricle (as occurs with eccentric hypertrophy in heart failure with reduced ejection fraction). Both S3 and S4 are best heard at the cardiac apex with the bell of the stethoscope. (Choice A) Aortic root dilation can cause aortic regurgitation, which is recognized by a decrescendo early diastolic murmur. Aortic regurgitation resulting from aortic root (as opposed to valvular) pathology is typically best heard at the right upper sternal border. (Choice B) An atrial septal defect typically causes a faint, crescendo-decrescendo systolic murmur (best heard at the left upper sternal border) caused by increased blood flow through the pulmonic valve (ie, pulmonic flow murmur). Splitting of S2 is wide and fixed. (Choice D) Mitral valve prolapse classically causes a midsystolic click followed by the late systolic murmur of mitral regurgitation (best heard at the cardiac apex). The click is relatively high pitched, and the timing varies with changes in LV blood volume. (Choice E) Pericardial effusion commonly occurs as a complication of acute pericarditis, which may be recognized by a triphasic pericardial friction rub best heard at the left lower sternal border with the patient leaning forward. Educational objective: An S4 is a low frequency, extra heart sound that occurs at the end of diastole (just before S1). It is caused by blood striking a stiff ventricular wall during atrial contraction; it can be a normal finding in elderly patients (eg, age >70), but typically indicates pathologic ventricular wall stiffening in younger patients (most commonly due to concentric left ventricular hypertrophy in response to chronic hypertension). __________ References: Association of the fourth heart sound with increased left ventricular end-diastolic stiffness. (http://www.ncbi.nlm.nih.gov/pubmed/18514937)

A 65-Year-Old Man with a Long History of Hypertension and Type