In distinguishing constrictive pericarditis from restrictive cardiomyopathy as a cause of right heart failure, which single parameter most reliably favours constrictive pericarditis?
- A Elevated serum NT-proBNP level
- B Septal bounce with exaggerated respirophasic variation in mitral inflow velocities ✓
- C Kussmaul sign in the neck veins
- D Prominent y descent on jugular venous pulse
Correct answer: B. Septal bounce with exaggerated respirophasic variation in mitral inflow velocities
Explanation
Constriction creates enhanced ventricular interdependence: with inspiration the septum shifts leftward (septal bounce) and mitral inflow velocity falls by more than 25 percent, a finding absent in restrictive cardiomyopathy. The distractors all overlap between the two diseases: Kussmaul sign, prominent y descent, and even a pericardial knock can occur in both, and NT-proBNP is typically higher in restrictive disease but is not specific. This interdependence principle is the classic discriminator tested in exams.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.