**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
First author: Grace M. Ferri
Email: gferri@bu.edu
Amyloidosis Center, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, USA

**Main Body of the Abstract**
Background: Myocardial toxicity from amyloidogenic light chains (aLCs) and architectural distortion from amyloid fibril deposition contribute to cardiac dysfunction in AL. Our transcriptomic analysis highlighted dysregulation of contractility in cardiomyocytes exposed to aLCs so we hypothesized that there could be clinically measurable differences in echocardiographic global longitudinal systolic strain (GLS).
Methods: Of 426 cardiac AL patients seen at Boston University Amyloidosis Center between 2011 and 2023, 29 patients had presumed LC-toxicity based on: (1) elevated cardiac biomarkers (BNP >81 pg/mL or NT-proBNP >899 pg/mL or troponin I >0.033 ng/mL, per institutional reference ranges); (2) echocardiographic interventricular septal diameter in diastole ([IVSd] <11 mm in males and <10 mm in females); (3) eGFR >60 mL/min/1.73m2; and (4) no late gadolinium enhancement on cardiac magnetic resonance imaging (if performed). GLS was post-processed manually (n=16) by one observer using TomTec 2D CPA. Median follow-up was 9.16 years (range 6.17 - 11.67). Overall survival (OS) was evaluated using Kaplan-Meier and log-rank tests.
Results: Among patients with presumed LC-toxicity, 72% (n = 22/29) had BU cardiac stage II and 28% (8/29) had stage III disease (Table 1). Eighty-one percent (13/16) had abnormal GLS. OS was similar between patients with LC-toxicity and increased IVSd among BU cardiac stage II disease.
Conclusions: A subset of AL patients demonstrate cardiac dysfunction as evidenced by abnormal GLS and increased cardiac biomarkers despite normal IVSd; this we postulate to mainly result from the myocardial toxic effects of aLCs. OS by BU cardiac stage was similar to patients with increased IVSd.



Abnormal global longitudinal strain correlates with amyloidogenic light chain-induced myocardial toxicity in patients without significant amyloid fibril deposition PB143 (#539)

We invite you to attend the XIX International Symposium on Amyloidosis to be held in Rochester, MN.

This symposium is organized as a hybrid meeting (with the focus on in-person) held from Sunday, May 26 through Thursday, May 30, 2024.

Together with the ISA Board and members of Mayo Clinic, a very attractive scientific hybrid program is being planned. The program will cover a variety of types of systemic amyloidosis: ATTR (hereditary and wild-type), AL (light-chain), AA and less frequent forms. There will be key lectures, specific symposia including those company sponsored, oral presentations and poster sessions of accepted abstracts.

COURSE DESCRIPTION
This program will provide a comprehensive review of state-of-the-art education in systemic amyloidosis: basic science, pathophysiology, diagnosis, current and emerging treatments. Scientific presentations will include competitive oral and poster abstracts. The rapid evolution of scientific discovery and expanding treatment options has created tremendous interest in the field and this meeting will fill and important gap in educating scientists and clinicians.