Cardiac Amyloidosis Definition Cardiac amyloidosis is an infiltrative restrictive cardiomyopathy caused by deposition of misfolded amyloid fibrils in the myocardium, leading to stiff, noncompliant ventricles and progressive heart failure with preserved ejection fraction (HFpEF). Major Types Affecting the Heart 1--AL (Light Chain) Amyloidosis Derived from immunoglobulin light chains (κ or λ). Associated with plasma cell dyscrasias (e.g., multiple myeloma). Rapid progression; median survival witho