The myocardium is rigid and noncompliant, impeding ventricular filling and raising cardiac filling pressures. Systolic performance is often reduced, but the overriding problem is impaired diastolic filling, which produces a clinical and hemodynamic picture that mimics constrictive pericarditis. The most common clinical manifestation is congestive heart failure. An early diastolic third sound is often heard. The heart is usually enlarged, and the ECG frequently shows low voltage.
Arrhythmias are common.
Two-dimensional echocardiography may be helpful in the diagnosis of cardiac amyloidosis. The cardiac walls are often thickened and show a characteristic granular, speckled appearance. Echocardiographic data can also provide prognostic information. In a large group of patients with amyloid heart disease, survival was negatively influenced by greater wall thickness and reduced systolic function, which were seen on two-dimensional echocardiography. Enhanced diffuse myocardial uptake of technetium-99m pyrophosphate in radionuclide scintigraphy has also been reported in patients with cardiac amyloidosis.