Constrictive Pericarditis Mimicking Heart Failure: Hemodynamic Catheterization as the Diagnostic Key.

Constrictive pericarditis (CP) is an uncommon but potentially reversible cause of heart failure, characterized by pericardial thickening, fibrosis, and loss of elasticity. Early recognition is essential because timely intervention can be curative. We report the case of a 64-year-old man with multiple comorbidities and recurrent heart failure admissions who was ultimately diagnosed with CP. Echocardiography suggested constrictive physiology (including annulus reversus), and hemodynamic catheterization demonstrated elevated right atrial pressure with rapid "y" descent, equalization of diastolic pressures across chambers, and a classic square root sign. He underwent pericardiectomy with an uneventful recovery and marked symptomatic improvement. This case highlights the diagnostic complexity of CP and underscores the central role of invasive hemodynamics in distinguishing it from other causes of heart failure, including restrictive cardiomyopathy and diastolic heart failure.