A 72-year-old man is hospitalized due to fatigue, orthopnea, and exertional dyspnea. The patient takes no medications and has not seen a physician in many years. He is a lifelong nonsmoker. His blood pressure is 110/60 mm Hg and pulse is 64/min. Examination reveals bibasilar crackles, elevated jugular venous pressure, and bilateral lower extremity pitting edema. His left ventricular end-diastolic pressure-volume is shown in the graph below (purple curve). Which of the following is the most likely cause of this patient's condition?

Question

A 72-year-old man is hospitalized due to fatigue, orthopnea, and exertional dyspnea.  The patient takes no medications and has not seen a physician in many years.  He is a lifelong nonsmoker.  His blood pressure is 110/60 mm Hg and pulse is 64/min.  Examination reveals bibasilar crackles, elevated jugular venous pressure, and bilateral lower extremity pitting edema.  His left ventricular end-diastolic pressure-volume is shown in the graph below (purple curve).  Which of the following is the most likely cause of this patient's condition?

Quizplus · Accepted Answer

11ec160b_3a9d_20d8_9249_93efc1ccd718_MD0001_00 This presentation (exertional dyspnea, orthopnea, bibasilar crackles, elevated jugular venous pressure, and lower extremity edema) is consistent with decompensated congestive heart failure (CHF). The left ventricular (LV) diastolic pressure-volume curve (purple curve in graph above) shows reduced LV compliance, indicating that diastolic dysfunction is the main contributing factor of the patient's CHF. LV diastolic pressure is determined by the blood volume in the LV cavity and compliance of the left ventricle. Conditions that decrease compliance lead to increased LV end-diastolic (LVED) pressures at the same LVED volumes. This causes a shift in the pressure-volume curve that goes upward and to the left. Higher LV filling pressures are transmitted back to pulmonary vasculature, leading to pulmonary edema. Impaired right ventricular filling or neurohormonal activation from low cardiac output is responsible for the peripheral edema and elevated jugular venous pressure. Restrictive cardiomyopathy (idiopathic or infiltrative disorders [eg, amyloidosis, sarcoidosis, hemochromatosis]) is an important cause of diastolic heart failure, also known as heart failure with preserved ejection fraction. Transthyretin (TTR), a protein tetramer produced in the liver, acts as a carrier of thyroxine and retinol. Mutations in the TTR gene can increase the tendency of TTR to misfold, producing an amyloid protein that infiltrates the myocardium (infiltrative cardiomyopathy). (Choices A, B, C, and E) Alcohol-induced cardiomyopathy, doxorubicin therapy, selenium deficiency, and viral myocarditis can all lead to dilated cardiomyopathy with LV systolic dysfunction. Systolic heart failure is typically characterized by increased LV volume and shifting of the pressure-volume curve to the right due to thinning of the ventricular wall (increased compliance). Educational objective: Diastolic heart failure (DHF) is caused by decreased ventricular compliance and is characterized by normal left ventricular (LV) ejection fraction, normal LV end-diastolic volume, and elevated LV filling pressures. Hypertension, obesity, and infiltrative disorders (eg, transthyretin-related amyloidosis, sarcoidosis) are important causes of DHF. __________ References: Cardiac transthyretin amyloidosis. (http://www.ncbi.nlm.nih.gov/pubmed/22888163) Cardiac amyloidosis: Where are we today? (http://www.ncbi.nlm.nih.gov/pubmed/26077367)

A 72-Year-Old Man Is Hospitalized Due to Fatigue, Orthopnea, and Exertional