RV enlargement and/or altered function resulting from primary lung disease; leads to RV hypertrophy and eventually to RV failure. Etiologies include:
- Pulmonary parenchymal or airway disease leading to hypoxemic vasoconstriction: e.g., chronic obstructive pulmonary disease (COPD), interstitial lung diseases, bronchiectasis, cystic fibrosis (Chaps. 131. Chronic Obstructive Pulmonary Disease and 134. Interstitial Lung Disease).
- Diseases of the pulmonary vasculature: e.g., recurrent pulmonary emboli, pulmonary arterial hypertension (PAH) (Chap. 127. Pulmonary Hypertension), vasculitis, sickle cell anemia.
- Inadequate mechanical ventilation (chronic hypoventilation). Kyphoscoliosis, neuromuscular disorders, marked obesity, sleep apnea (Chap. 137. Sleep Apnea).
Depend on underlying disorder but include dyspnea, cough, fatigue, and sputum production (in parenchymal diseases).
Tachypnea, RV impulse along left sternal border, loud P2, right-sided S4; cyanosis, clubbing are late findings. If RV failure develops, elevated jugular venous pressure, hepatomegaly with ascites, pedal edema; murmur of tricuspid regurgitation is common.
RV hypertrophy and RA enlargement (Chap. 111. Electrocardiography); tachyarrhythmias are common.
CXR shows RV and pulmonary artery enlargement; if PAH present, tapering of the pulmonary artery branches. Chest CT identifies emphysema, interstitial lung disease, and acute pulmonary embolism; V/Q scan is more reliable for diagnosis of chronic thromboemboli. Pulmonary function tests and ABGs characterize intrinsic pulmonary disease.
RV hypertrophy; LV function typically normal. RV systolic pressure can be estimated from Doppler measurement of tricuspid regurgitant flow. If imaging is difficult because of air in distended lungs, RV volume and wall thickness can be evaluated by MRI.
Can confirm presence of pulmonary hypertension and exclude left-heart failure as cause.
Treatment: COR Pulmonale Aimed at underlying pulmonary disease and may include bronchodilators, antibiotics, oxygen administration, and noninvasive mechanical ventilation. For pts with PAH, pulmonary vasodilator therapy may be beneficial to reduce RV afterload (Chap. 127. Pulmonary Hypertension). See Chap. 133. Pulmonary Thromboembolism and Deep-Vein Thrombosis for specific treatment of pulmonary embolism. If RV failure is present, treat as heart failure, instituting low-sodium diet and diuretics; digoxin is of uncertain benefit and must be administered cautiously (toxicity increased due to hypoxemia, hypercapnia, acidosis). Loop diuretics must also be used with care to prevent significant metabolic alkalosis that blunts respiratory drive. |
For a more detailed discussion, see Mann DL, Chakinala M: Heart Failure: Pathophysiology and Diagnosis, Chap. 279, p. 1500, and Mehra MR: Heart Failure: Management, Chap. 280, p. 1507, in HPIM-19. |
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