Sunday, November 2, 2014

Cor pulmonale:

Cor pulmonale:

a. Is an early sign of COPD and will respond to bronchodilator therapy.
b. Is more commonly seen in patients in whom emphysema predominates.
c. Produces a left bundle-branch pattern on the ECG.
d. Results from chronic hypoxia inducing pulmonary hypertension.
e. Results from the cardiac toxicity of inhaled bronchodilators.

The answer is d. Pulmonary dysfunction causing hypoxia reduces myocardial oxygen supply while increasing cardiac output demand by perfusing all tissues with suboptimally oxygenated blood. Hypoxia leads to pulmonary arteriolar vasoconstriction, and along with various destructive processes such as emphysema and pulmonary fibrosis, which reduces lung vascular bed area, causes elevation of pulmonary artery pressures. Chronic increases in pulmonary arterial pressure lead to right ventricular hypertrophy and dilation. When compensatory mechanisms fail, the patient develops clinical evidence of right heart failure (cor pulmonale), usually with left ventricular output
preserved, at least at rest.

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