A 54-year-old man comes to the emergency department due to severe shortness of breath and palpitations. During initial assessment, pulse oximetry shows 83%. Diffuse, bilateral crackles are heard on lung auscultation. Chest x-ray is consistent with pulmonary edema. ECG shows atrial fibrillation with rapid ventricular response. The patient dies despite appropriate medical care. Autopsy is performed and gross examination of the heart is shown below. Histologic examination of the myocardial tissue reveals thick myocardial fibers with large, hyperchromatic nuclei as well as mild interstitial fibrosis. Which of the following is the most likely diagnosis?

Question

A 54-year-old man comes to the emergency department due to severe shortness of breath and palpitations.  During initial assessment, pulse oximetry shows 83%.  Diffuse, bilateral crackles are heard on lung auscultation.  Chest x-ray is consistent with pulmonary edema.  ECG shows atrial fibrillation with rapid ventricular response.  The patient dies despite appropriate medical care.  Autopsy is performed and gross examination of the heart is shown below.  Histologic examination of the myocardial tissue reveals thick myocardial fibers with large, hyperchromatic nuclei as well as mild interstitial fibrosis.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec160b_38e3_8996_9249_17d2f9c502cd_MD0001_00 This individual developed acute decompensated heart failure (eg, shortness of breath, pulmonary edema) and likely died due to subsequent cardiogenic shock. Autopsy findings reveal uniformly thickened left ventricular (LV) walls and a small LV cavity, which are consistent with concentric LV hypertrophy. Concentric LV hypertrophy most commonly results from prolonged systemic hypertension as myocardial fibers are added in parallel to increase contractile strength and handle the increased pressure load. As concentric hypertrophy worsens, it can manifest clinically as hypertensive heart disease, consisting of impaired diastolic filling and heart failure with preserved ejection fraction. The elevated diastolic filling pressures are transmitted back to the left atrium, causing atrial dilation and altered conduction that predisposes to atrial fibrillation. Loss of atrial contraction can lead to a dramatic reduction in left ventricular filling in patients with diastolic heart failure and can precipitate acute decompensation (as likely occurred in this patient). On histopathology, hypertensive heart disease demonstrates transverse thickening of cardiomyocytes with prominent hyperchromatic nuclei. The increased myocardial mass may be inadequately supplied with oxygen, contributing to cellular necrosis and interstitial fibrosis. (Choice A) Cardiac amyloidosis involves deposition of abnormal proteins in the myocardium and can lead to restrictive cardiomyopathy, which is characterized by impaired diastolic filling due to stiffening, rather than thickening, of the ventricular walls. Histopathology in cardiac amyloidosis reveals collections of pink amorphous material abutting normal cardiomyocytes. (Choice C) Hypertrophic cardiomyopathy involves localized, rather than uniform, thickening of the LV walls, predominantly affecting the interventricular septum. As in hypertensive heart disease, histopathology can reveal cardiomyocyte thickening, hyperchromatic nuclei, and interstitial fibrosis; however, cardiomyocyte disarray (loss of organized cellular alignment) is also expected. (Choice D) Mitral stenosis causes impaired diastolic filling and can lead to decompensated heart failure and atrial fibrillation; however, it does not increase the pressure load on the left ventricle and does not cause concentric hypertrophy. (Choice E) Pulmonary arterial hypertension results from primary changes in the pulmonary arteries that increase pulmonary arterial resistance. The elevated pressure load on the right ventricle can lead to concentric right ventricular hypertrophy and right-sided heart failure. Pulmonary edema is not present in right-sided heart failure. Educational objective: Concentric left ventricular (LV) hypertrophy involves uniform thickening of the LV walls with reduction in LV cavity size and most commonly results from prolonged systemic hypertension. It can progress to hypertensive heart disease with impaired diastolic filling and heart failure with preserved ejection fraction. Histopathology demonstrates transverse thickening of cardiomyocytes with prominent hyperchromatic nuclei and interstitial fibrosis.

A 54-Year-Old Man Comes to the Emergency Department Due to Severe