It is excessive stiffness of the heart resulting in an inability of the heart to fill properly (Eur Heart J 1998; 19: 990-1003).
This is in contrast to systolic dys-function, where contractility is impaired.
Patients have clinical features of left heart failure but normal systolic function by echocardiography or radionuclide ven-triculography.
It is a feature of hypertrophic cardiomyopathy, severe left ventricular hypertrophy (e.g. aortic stenosis or hypertension) and restrictive cardiomyopathy (e.g. amyloidosis).
Treatment is directed towards the underlying cause.