The principal symptoms are slowly progressive dyspnea, fatigue, and weakness. Chronic edema, hepatic congestion, and ascites are usually present. Ascites often seems out of proportion to the degree of peripheral edema. The examination reveals these signs and a characteristically elevated jugular venous pressure with a rapid y descent. This can be detected at bedside by careful observation of the jugular pulse and noting an apparent increased pulse wave at the end of ventricular systole (due to the relative accentuation of the v wave by the rapid y descent). Kussmaul sign—a failure of the JVP to fall with inspiration—is also a frequent finding. The apex may actually retract with systole and a pericardial “knock” may be heard in early diastole. Pulsus paradoxus is unusual. Atrial fibrillation is common.
At times, constrictive pericarditis is extremely difficult to differentiate from restrictive cardiomyopathy and the two may coexist. When unclear, the use of both noninvasive testing and cardiac catheterization is required to sort out the difference.
The chest radiograph may show normal heart size or cardiomegaly. Pericardial calcification is best seen on the lateral view and is uncommon. It rarely involves the LV apex, and finding of calcification at the LV apex is more consistent with LV aneurysm.
Echocardiography rarely demonstrates a thickened pericardium. A septal “bounce” reflecting the rapid early filling is common, though. RV/LV interaction may be demonstrated by an inspiratory reduction in the mitral inflow Doppler pattern of greater than 25%, much as in tamponade. Usually the initial mitral inflow into the LV is very rapid, and this can be demonstrated as well by the Doppler inflow (E wave) pattern. Other echocardiographic features can also help reveal constrictive physiology.
These imaging tests are only occasionally helpful. Pericardial thickening of more than 4 mm must be present to establish the diagnosis, but no pericardial thickening is demonstrable in 20–25% of patients with constrictive pericarditis. Some MRI techniques demonstrate the septal bounce and can provide further evidence for ventricular interaction.
4. Cardiac catheterization
This procedure is often confirmatory or can be diagnostic in difficult cases where the echocardiographic features are unclear or mixed. As a generality, the pulmonary pressure is low in constriction (as opposed to restrictive cardiomyopathy). In constrictive pericarditis, because of the need to demonstrate RV/LV interaction, cardiac catheterization should include simultaneous measurement of both the LV and RV pressure tracings with inspiration and expiration. This interaction can be demonstrated by cardiac MRI. Hemodynamically, patients with constriction have equalization of end-diastolic pressures throughout their cardiac chambers, there is rapid early filling then an abrupt increase in diastolic pressure (“square-root” sign), the RV end-diastolic pressure is more than one-third the systolic pressure, simultaneous measurements of RV and LV systolic pressure reveal a discordance with inspiration (the RV rises as the LV falls), and there is usually a Kussmaul sign (failure of the RA pressure to fall with inspiration). In restrictive cardiomyopathy, there is concordance of RV and LV systolic pressures with inspiration. The area of the RV pressure tracing may also be less in expiration and greater during inspiration, reflecting the variability in filling of the RV with respiration. The ratio of the RV tracing area to the LV tracing area should increase with inspiration if constriction is present; this is due to the increased RV filling and higher RV systolic pressure with inspiration while the LV systolic pressure falls and the LV tracing area becomes less. These findings differ from restrictive cardiomyopathy in which the LV diastolic pressure is usually greater than the RV diastolic pressure by 5 mm Hg, there is pulmonary hypertension, and simultaneous measurements of the RV and LV systolic pressure reveal a concordant drop in the peak systolic ventricular pressures during inspiration with no change in the RV/LV tracing area ratio with inspiration. The pulmonary venous pressure drop with inspiration more than the LVEDP and that relationship can also indicate a constrictive process by comparing LVEDP and PCWP during that time.