What is the major functional abnormality in restrictive cardiomyopathy?

The defining abnormality of RCM is **poor ventricular compliance**, which limits adequate ventricular filling during diastole. Systolic function may remain preserved until later in the disease course. The other choices do not describe the core mechanism in the slides. **Key takeaway:** RCM is primarily a filling disorder caused by stiff, poorly compliant ventricles.\n\n**Glossary:** **Compliance**: The ability of a structure to expand in response to filling.