Constrictive pericarditis (CP) is a form of diastolic heart failure that arises because an inelastic pericardium inhibits cardiac filling. This disorder must be considered in the differential diagnosis for unexplained heart failure, particularly when the left ventricular ejection fraction is preserved. Risk factors for the development of CP include prior cardiac surgery and radiation therapy, but most cases are still deemed to be idiopathic. Making the diagnosis may be challenging and requires meticulous echocardiographic assessment, often supplemented by cross-sectional cardiac imaging and haemodynamic catheterisation. The key pathophysiological concepts, which serve as the basis for many of the diagnostic criteria, remain: (1) dissociation of intrathoracic and intracardiac pressures and (2) enhanced ventricular interaction. Complete surgical pericardiectomy is the only effective treatment for chronic CP. A subset of patients with subacute inflammatory CP, often identified by cardiac MRI, may respond to anti-inflammatory treatments.