Abstract 10310: Sudden Cardiac Death in Recently Diagnosed Patients With Light-Chain Cardiac Amyloidosis

Introduction: Untreated, light-chain (AL) cardiac amyloidosis is associated with a median survival of 6-months when diagnosed in advanced stage. However, current plasma cell-targeting therapies have drastically improved end-organ function and life expectancy. Yet, a portion still die despite appropriate treatment. We hypothesize this is from sudden cardiac death (SCD). Aim: To determine the incidence of and clinical characteristics associated with 90-day SCD after diagnosis of AL amyloidosis. Methods: Clinical, electrocardiographic, imaging, treatment, and outcomes were abstracted from consecutive patients diagnosed with AL amyloidosis from 2014-2022 at UT Southwestern Medical Center. Statistics were reported as mean and standard deviation. Results: In our study cohort (N=189) patients with AL amyloidosis, 18 patients (66% male, age 65 ± 9.5 y) died by 90-days (9.5%). Of these, 14 patients died by 60-days (7.3%), and 10 patient died by 30-days (5.2%). There were 7 cardiac deaths (3.6%): including one PEA arrest (0.5%), one in-hospital cardiac arrest (0.5%) and five unwitnessed out-of-hospital cardiac arrests (2.6%). Among cardiac deaths, 3 patients had endomyocardial tissue consistent with AL. Revised Mayo Stage was 66% III, 33% IV. Six patients had at least one dose of chemotherapy with bortezomib, cyclophosphamide and dexamethasone (CyBorD), Velcade/Dexamethasone, or Daratumumab/CyBorD, and 5 had at least one full cycle. The LVEF was 48.9 ± 8.1, QTc 483 ± 50 ms, interventricular septal thickness was 1.2 cm ± 0.4 cm. CMR was obtained in 4 of 7 patients, with late gadolinium enhancement present in a diffuse pattern in 75%, average LVEDV 59 ± 9.5 mL. Mean time to death was 37.2 ± 21 days. Conclusions: Sudden cardiac death may be a significant contributor to mortality among patients with newly diagnosed AL amyloidosis. These observations warrant confirmation in larger cohorts and may identify an unmet need to enhance risk stratification for SCD in this population.