What is the definitive diagnostic test for cor pulmonale?

• A. Echo
• B. Cardiac catheterization
• C. EKG
• D. MRI

Answer: (B)

Cor pulmonale stems from pulmonary hypertension causing chronic pressure overload of the right ventricle, leading to its hypertrophy and eventual failure. The definitive test to diagnose pulmonary hypertension and define its hemodynamics is right heart catheterization, which directly measures pressures in the right atrium, right ventricle, and pulmonary artery, and computes pulmonary vascular resistance. It also provides the wedge (left atrial) pressure to distinguish pre-capillary from post-capillary PH, guiding both diagnosis and management. Noninvasive tests like echocardiography can estimate pulmonary pressures and screen for PH, and MRI can assess right ventricular structure and function, but neither yields the exact hemodynamic data obtained with catheterization. An ECG might show signs of right heart strain but does not quantify pressures. Therefore, the most definitive diagnostic test is right heart catheterization.