Restrictive cardiomyopathy is a condition characterized by normal or subnormal left ventricular cavity size and systolic function but with increased myocardial stiffness. This makes the ventricle incompliant with predominant filling in early diastole. When atrial systolic function is maintained, the ventricle may accommodate a small volume of blood during atrial systole but at the expense of a further rise in end diastolic pressure. These physiological disturbances are associated with raised left atrial pressure, atrial enlargement, and arrhythmias.