A Near-Miss Event: Constrictive Pericarditis Misdiagnosed as Heart Failure With Preserved Ejection Fraction.

Constrictive pericarditis (CP) is often misdiagnosed, making echocardiography essential for initial evaluation. We present a case of misdiagnosed constrictive pericarditis in a 66-year-old female with rheumatoid arthritis who presented with shortness of breath. A transthoracic echocardiogram (TTE) performed by a cardiologist initially reported diastolic dysfunction, leading to a diagnosis of heart failure with preserved ejection fraction (HFpEF), and she was discharged on diuretics. Despite adherence to therapy, she was readmitted multiple times for worsening symptoms over 18 months. A repeat TTE revealed ventricular septal bounce in early diastole and a positive annulus reversus sign, both of which were missed on the initial study. Ventricular septal bounce in early diastole reflects abnormal interventricular dependence due to a noncompliant, often thickened pericardium, which restricts diastolic filling and causes the septum to move abruptly with changes in intracardiac pressures, and the annulus reversus sign means that the medial (septal) mitral annular early diastolic velocity (e') exceeds the lateral e' which is a result of pericardial tethering of the lateral annulus and is a distinguishing feature of constrictive pericarditis, as opposed to restrictive cardiomyopathy, where both e' velocities are reduced but the normal relationship is preserved. Respiratory cycle monitoring and hepatic vein examination, critical for CP diagnosis, were not performed initially. Cardiac magnetic resonance imaging (MRI) was performed for the high suspicion of CP, which demonstrated pericardial thickening with septal bounce and interventricular dependence, confirming CP. The patient underwent pericardiectomy with full recovery of her symptoms. This case highlights the diagnostic challenge of CP, given its nonspecific symptoms, and underscores the importance of expert echocardiographic evaluation, multimodality imaging, and cardiac catheterization, which remains the gold standard, as CP can be easily overlooked.