A 66-year-old man comes to the office for evaluation of progressive shortness of breath for the past 2 months. The patient used to walk nearly a mile a day without difficulty. More recently, however, he feels "out of breath" and tires easily after walking a few blocks. The patient has gained 4 kg (8.8 lb) over a similar period. He has also had a persistent, dry cough that is worse at night when he is lying in bed. The patient has had no fever, chills, or night sweats. He has a history of hypertension. He is a former smoker who quit 5 years ago. Until 4 years ago, the patient worked as an engineer at a local steel mill. Temperature is 36.1 C (97 F), blood pressure is 154/90 mm Hg, pulse is 92/min and regular, and respirations are 20/min. Pulse oximetry is 94% on room air. BMI is 47.4 kg/m². The lungs are clear on auscultation. S1 and S2 are normal, and the point of maximal impulse is not palpable due to the patient's body habitus. The abdomen is soft and nontender. There is 1+ pretibial edema bilaterally. Initial complete blood count and complete metabolic panel are unremarkable. B-type natriuretic peptide is 95 pg/mL (normal: 100-400). ECG shows normal sinus rhythm with evidence of left atrial enlargement. Chest x-ray is shown in the exhibit. Echocardiography reveals concentric left ventricular hypertrophy, left atrial enlargement, and a left ventricular ejection fraction of 60%. Which of the following is the most likely cause of this patient's current symptoms? A)Chronic obstructive pulmonary disease B)Deconditioning C)Heart failure with preserved ejection fraction D)Interstitial lung disease E)Obesity hypoventilation syndrome

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Explanation: 11ec2b69_c10b_8217_8f63_d3f63abbf9bc_MD0005_00 This patient likely has chronic heart failure with preserved ejection fraction (HFpEF), which accounts for approximately half of cases of heart failure. Chronic systemic hypertension and obesity, as seen in this patient, are usually the most prominent contributors to HFpEF. They cause concentric left ventricular (LV) hypertrophy and myocardial interstitial fibrosis that lead to diastolic dysfunction and eventual decompensated volume overload. The diagnosis of heart failure, both diastolic and systolic, is based primarily on history and physical examination. Dyspnea is highly sensitive but poorly specific for heart failure. In contrast, orthopnea and paroxysmal nocturnal dyspnea (eg, dry cough worse when lying down at night, as in this patient), along with jugular venous distension (JVD), lower extremity edema, and an S3, have relatively high specificity but low sensitivity. Several testing and imaging modalities can aid diagnosis: B-type natriuretic peptide <100 pg/mL can help exclude clinically significant heart failure. However, obesity (as in this patient whose BMI is 47.4 kg/m²) often causes falsely low levels. Chest x-ray often shows pulmonary edema, which typically begins as interstitial edema (ie, Kerley B lines) and can progress to alveolar edema (ie, alveolar opacification). Echocardiography provides an estimate of LV ejection fraction and can reveal left atrial dilation. LV ejection fraction is normalin HFpEF, and diastolic dysfunction is not always detectable. The degree of pulmonary edema can vary in decompensated heart failure because the pulmonary lymphatics can gradually increase fluid outflow rate up to 10 times from baseline when needed. Therefore, significant alveolar edema (ie, crackles on examination) is typical with acute heart failure (ie, the lymphatics have not had time to adapt), but less prominent pulmonary edema (ie, interstitial edema only) is common in chronic heart failure. The pulmonary lymphatics effectively offload fluid to the central venous system; evidence of elevated central venous pressure (eg, JVD, lower extremity edema) persists despite minimal pulmonary edema. (Choices A and D) Chronic obstructive pulmonary disease and interstitial lung disease typically cause dyspnea and cough. However, this patient's cough that is worse while lying suggests paroxysmal nocturnal dyspnea. In addition, his weight gain and pulmonary interstitial edema on chest x-ray further suggest heart failure. (Choice B) Although sedentary patients can develop dyspnea from cardiopulmonary deconditioning, it would not explain this patient's left atrial dilation and symptoms at rest. (Choice E) Obesity hypoventilation syndrome often presents with dyspnea and may lead to right-sided heart failure, resulting in JVD, lower extremity edema, and hepatomegaly. However, this would not explain PND and pulmonary interstitial edema. In addition, a compensatory increase in serum bicarbonate is typically present with obesity hypoventilation syndrome. Educational objective: Heart failure with preserved ejection fraction is a common cause of heart failure. Chronic heart failure often manifests with mild interstitial edema (ie, Kerley B lines on chest x-ray) without alveolar edema (ie, no crackles on examination). References: Heart failure preserved ejection fraction (HFpEF): an integrated and strategic review. (http://www.ncbi.nlm.nih.gov/pubmed/26404098) Obesity and suppressed B-type natriuretic peptide levels in heart failure. (http://www.ncbi.nlm.nih.gov/pubmed/15120816)

A 66-Year-Old Man Comes to the Office for Evaluation of Progressive