Chapter 76: Cor Pulmonale: The Heart in Parenchymal Lung Disease
The pulmonary circulation is characterized by all of the following except:
A. It carries venous deoxygenated blood
D. Normal mean pulmonary pressure is < 20 mm Hg at rest
E. Pulmonary vascular resistance (PVR) decreases with increased cardiac output
The answer is C. (Hurst’s The Heart, 14th Edition, Chap. 76) The pulmonary circulation (with the exception of the bronchial arteries that deliver oxygenated blood from the left heart) is characterized not only by the delivery of venous deoxygenated blood to the alveoli for oxygen uptake (option A is incorrect), but also by low resistance (option B is incorrect) and large capacitance (option C is correct). This capacitance allows the lungs to accommodate a wide range of blood flows with little increase in pulmonary arterial pressure.1 Normal mean pulmonary pressure is < 20 mm Hg at rest (option D is incorrect), with a mean level > 25 mm Hg diagnostic of PH.2 Although pulmonary pressures do rise with exercise, PVR normally drops further with exercise to accommodate the marked increase in cardiac output (option E is incorrect).
Which of the following lung diseases does not manifest as a typical cor pulmonale syndrome?
A. Acute pulmonary embolism
B. Chronic obstructive pulmonary disease (COPD)
E. Obstructive sleep apnea (OSA)
The answer is A. (Hurst’s The Heart, 14th Edition, Chap. 76) Cor pulmonale describes the pathological changes and associated signs and symptoms of right ventricular failure resulting from PH.3 Chronic cor pulmonale is typically a manifestation of various lung diseases, such as COPD (option B is incorrect), bronchiectasis (option C is incorrect), sarcoidosis (option D is incorrect) and OSA (option E is incorrect). Acute pulmonary embolism can lead to acute right heart failure, which has been termed acute cor pulmonale. The cardiac response to “acute cor pulmonale” differs from the typical cor pulmonale syndrome, which is characterized by early RVH and subsequent late right ventricular dilatation. In contrast, in acute pulmonary embolism, the right ventricle dilates acutely without intervening hypertrophy, leading to a volume overload rather than pressure overload right ventricular failure (option A is correct).
Which of the following statements about the pathophysiology of cor pulmonale is correct?
A. Pulmonary vascular remodeling ...