Constrictive pericarditis in the modern era: a diagnostic dilemma.

Constrictive pericarditis is caused by fibrosis and calcification of the pericardium, processes that inhibit diastolic filling of the heart. This condition has posed a diagnostic dilemma since it was first recognised clinically. Although many diagnostic approaches have become available subsequently, the diagnostic challenge remains. Because surgical intervention can provide complete relief of symptoms in many patients, accurate diagnosis of this disorder is important. In the past, it was necessary to diVerentiate constrictive pericarditis from other causes of right sided heart failure, such as pulmonary embolism, pulmonary hypertension, right ventricular infarction, mitral stenosis, and left ventricular systolic dysfunction. Now, with two dimensional and Doppler echocardiography, these other causes of right sided heart failure can be diagnosed or excluded. Imaging methods such as computed tomography and magnetic resonance scanning can measure pericardial thickness, which is usually increased in patients with constrictive pericarditis. However, the aetiology of constrictive pericarditis has changed during the past few decades, leading to further diagnostic uncertainties. In the past, many patients with constrictive pericarditis had severe calcification of the entire pericardium, usually secondary to tuberculous pericarditis. Today, other causes of constrictive pericarditis are common, such as mantle chest radiation and open heart surgical procedures. DiVuse calcification of the pericardium occurs much less commonly in these patients with constrictive pericarditis and the pericardial thickness may even be normal. After radiation therapy or an open heart operation, constrictive pericarditis, myocardial restrictive disease, or a combination of both may develop. Thus, patients today have signs and symptoms of right sided heart failure that are disproportionate to left ventricular dysfunction or valvar disease. The challenge is to determine whether abnormalities are caused by pericardial restraint, myocardial restriction, or both. 5 6 If pericardial and myocardial disease are present, the decision to proceed with the operation depends on the degree to which the abnormal pericardium contributes to the increased intracardiac pressures. Previous diagnostic studies, including cardiac catheterisation, have not been able to make this determination. Insights into the pathophysiology of constrictive and restrictive disorders have emerged, describing respiratory changes in pressures and flows. To meet the diagnostic challenge, non-invasive and invasive diagnostic testing must frequently be informed by a knowledge of pathophysiological mechanisms.