Pericardial Constriction Pericardial constriction is characterized by a thickened, inelastic, and a noncompliant pericardium that limits diastolic expansion of the ventricles Constriction generally involves the entire pericardium although localized constriction is occasionally seen.3,4,78,100,101 It is also known as chronic constrictive pericarditis In reality, chronic constrictive pericarditis is a misnomer as the constriction is not necessarily chronic and pericardium is hardly ever inflamed Hence, it is preferable to use the term “pericardial constriction.” Tuberculosis is the most common cause of pericardial constriction worldwide.3,4,78 Idiopathic or viral pericarditis and constriction following cardiac surgery are increasingly becoming common in developed countries (see Table 57.1).3,6,79 Radiation-induced pericardial constriction may present after a long latency of 2 decades.3,78 Pathophysiology In pericardial constriction, similar to tamponade physiology, the left and right ventricles compete for filling in a “fixed” and noncompliant space As a result, filling pressures in all the cardiac chambers and in systemic as well as pulmonary veins are elevated Unlike tamponade, however, early ventricular filling is exaggerated In mid-diastole, stiff pericardium abruptly halts ventricular filling when the cardiac volume exceeds pericardial reserve volume (see Fig 57.1).3,6,102–107 Severely restricted ventricular filling leads to elevated systemic venous pressure and a relatively fixed cardiac output Subsequent neurohormonal changes contribute to fluid retention.3,6 Despite elevated pressure in pulmonary veins, dyspnea is rare This is possibly related to the lack of rise in atrial natriuretic peptide levels in pericardial constriction.108,109 Significant ascites by interfering with the movement of the diaphragm can sometimes cause orthopnea Thickened pericardium, unlike pericardial effusion, impedes transmission of thoracic pressure to the cardiac chambers As a result, pressure in the pulmonary veins falls with no simultaneous reduction in left ventricular diastolic pressure Consequently, pulmonary vein-to-left-ventricle pressure gradient is reduced or completely abolished during inspiration, causing marked reduction in left ventricular filling This impaired left ventricular filling during inspiration allows preferential filling of the right ventricle with the opposite happening during expiration (exaggerated ventricular interdependence).105,106 Accentuated early diastolic ventricular filling and nontransmission of thoracic pressure accounts for most of the hemodynamic differences in pericardial constriction compared with cardiac tamponade Clinical Presentation Pericardial constriction typically presents with symptoms and signs of rightsided heart failure Pedal edema is the rule with varying degrees of ascites and pleural effusion The enlarged liver may be tender and may have systolic pulsations of tricuspid regurgitation If left untreated, patients present with recurrent pleural effusion, ascites, and anasarca Chronic malnutrition and high metabolic rate lead to muscle wasting and cachexia In advance stages, cardiac cirrhosis may ensue Physical examination shows markedly elevated JVP Exaggerated ventricular filling during early diastole allows rapid “y” descent (Friedreich sign) A combination of prominent “y” descent and normal “x,” along with nearly equal “a” and “v” waves, gives JVP a typical “M” or “W” contour The JVP fails to fall or may paradoxically rise during inspiration (Kussmaul sign) Paradoxical pulse, which is present in almost all cases of established tamponade, is seen in only one-third patients with pericardial constriction Pericardial knock, an early diastolic high-frequency sound, is the auscultatory hallmark of pericardial constriction and coincides with the mid-diastolic pericardial restrain.3,4 The signs and symptoms of pulmonary venous hypertension are rarely present Varying degrees of tricuspid regurgitation may appear The development of atrial fibrillation is seen in one-third of patients and can cause further hemodynamic compromise Investigations ECG shows nonspecific T wave changes and reduced voltage As highlighted before, atrial fibrillation is seen in up to one-third of patients On chest x-ray, cardiac silhouette is usually normal Cardiomegaly may be seen in patients with coexisting pericardial effusion Pericardial calcification is seen in a minority of patients It is commonly seen over the right atrium, atrioventricular groove, and diaphragmatic surface of the cardiac silhouette (Fig 57.7).110 Pleural effusion is common and pulmonary venous redistribution may be seen in a few cases with markedly elevated left-sided filling pressure FIG 57.7 Chest radiograph (posteroanterior view) from a child with pericardial constriction showing calcification of the diaphragmatic surface of the pericardium Echocardiography Echocardiography remains the main investigation modality for cases suspected to have pericardial constriction However, it is not accurate for assessment of pericardial thickness Abrupt shift of ventricular septum during early diastole manifests as “septal bounce.” The septum is also shifted leftward during inspiration with the opposite happening during expiration Systemic veins and hepatic veins are dilated with absent or minimal inspiratory collapse Elevated right ventricular early diastolic pressure may cause premature opening of pulmonary valve.3,6 Doppler interrogation reveals exaggerated respiratory variation in both mitral and tricuspid inflow velocities, with the latter being 180