Which feature best distinguishes constrictive pericarditis from restrictive cardiomyopathy on echocardiography?

Which feature best distinguishes constrictive pericarditis from restrictive cardiomyopathy on echocardiography?

• A. Marked respiratory variation in LV filling with pericardial thickening.
• B. Reduced diastolic filling with minimal respiratory variation.
• C. Annulus reversus is definitively diagnostic.
• D. Absence of pericardial thickening.

Answer: (A)

The main idea is that constrictive pericarditis causes the heart to fill under a fixed external constraint, leading to pronounced changes in filling with respiration. Because the rigid pericardium couples both ventricles and creates strong ventricular interdependence, inspiration markedly alters LV filling. In echo Doppler, this shows up as a substantial respiratory variation in transmitral flow velocities, reflecting that during inspiration the LV fills less while the RV fills more. When you add pericardial thickening, this finding becomes even more characteristic, since the thickened pericardium reinforces the constraint. Restrictive cardiomyopathy, by contrast, involves a stiff myocardium rather than a constraining shell, so diastolic filling is reduced but there’s not the same level of respiratory variation driven by intrathoracic pressure changes. That’s why marked respiratory variation with pericardial thickening points toward constriction rather than restriction. Other signs like annulus reversus can support constrictive physiology but aren’t definitively diagnostic on their own, and absence of pericardial thickening would make constriction less likely despite other findings.

The main idea is that constrictive pericarditis causes the heart to fill under a fixed external constraint, leading to pronounced changes in filling with respiration. Because the rigid pericardium couples both ventricles and creates strong ventricular interdependence, inspiration markedly alters LV filling. In echo Doppler, this shows up as a substantial respiratory variation in transmitral flow velocities, reflecting that during inspiration the LV fills less while the RV fills more. When you add pericardial thickening, this finding becomes even more characteristic, since the thickened pericardium reinforces the constraint.

Restrictive cardiomyopathy, by contrast, involves a stiff myocardium rather than a constraining shell, so diastolic filling is reduced but there’s not the same level of respiratory variation driven by intrathoracic pressure changes. That’s why marked respiratory variation with pericardial thickening points toward constriction rather than restriction.

Other signs like annulus reversus can support constrictive physiology but aren’t definitively diagnostic on their own, and absence of pericardial thickening would make constriction less likely despite other findings.