Extracellular Volume Mapping by Cardiac MRI Predicts Sudden Cardiac Death in AL Amyloidosis: A South Asian Cohort...

To correlate extracellular volume (ECV) measurement at diagnosis with sudden cardiac death in patients with AL amyloidosis from South Asia. This ambispective study included 188 AL amyloidosis patients from January 2000 to October 2024 at Amrita Institute of Medical Sciences, Kochi. Patients had serum free light chain restriction (FLC-diff ≥ 18 mg/dL) and biopsy-proven amyloidosis and/or cardiac amyloidosis phenotype. ECV was calculated from T1 mapping in cardiac MRI. Normal ECV was defined as < 25%.Of 188 patients (median age 64.5 years, male: female 2:1), 43 underwent cardiac MRI with 22 having evaluable ECV. Five patients had normal ECV (< 25%) and 17 had abnormal ECV (≥ 25%). Patients with abnormal ECV showed significantly higher baseline lambda light chains (558 vs. 46 mg/dL) and NT-proBNP (5587 vs. 1254 pg/mL). All 10 deaths occurred in the abnormal ECV group versus none in the normal ECV group (p < 0.05). ECV values were significantly higher in patients with sudden cardiac death (p = 0.03). Abnormal ECV demonstrated perfect sensitivity (100%) but lower specificity (41.67%) for predicting mortality. Although limited by its sample size, ECV mapping can be a useful tool predicting survival in AL amyloidosis patients, with abnormal ECV predicting sudden cardiac death in this South Asian cohort.