**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.**
Nerea Mora-Ayestarán, Hospital Universitario Puerta de Hierro, Madrid, Spain

**Main Body of the Abstract**
Background: There is controversy regarding the usefulness of heart failure (HF) drugs in ATTR-CM. The aim of this study was to assess the clinical impact at short term of discontinuing beta-blockers (BB) in ATTR-CM.
Methods: This study was a prospective assessment of ATTR-CM patients who discontinued BB at their initial evaluation at Hospital Universitario Puerta de Hierro, Madrid, Spain. BB are systematically discontinued in our center unless patients have history of symptoms due to uncontrolled atrial fibrillation (AF). Patients underwent serial clinical assessment including NtproBNP, 6-minute walk test (6MWT), and Kansas City Cardiomyopathy Questionnaire (KCCQ) at initial visit and at 1 month.
Results: We studied 26 ATTR-CM patients who discontinued BB at their initial evaluation and did not have any other treatment modification. One patient required reintroduction of BB due to symptomatic uncontrolled AF and 3 subjects did not return for the 1-month follow-up visit despite they have not restarted BB afterwards. 22 patients (20 men, 77.5±5.3 years, 21 ATTRwt, 14 NYHA ≥II, LVEF 53.3±8.5% and 13 with AF) completed the evaluation. One month after BB withdrawal, 6MWT distance increased by 21±6 m (from 329.7±91.0 to 350.6±96.8; p<0.001), KCCQ increased by 9±3 points (66.5±26.4 to 75.4±23.5; p<0.001) while NTproBNP decreased (2842±2278 to 2258.86±1662 pg/mL; p<0.001). NYHA improved in 5/14 patients (35%) who had NYHA ≥II. Heart rate increased from 68.4±12.6 to 81.1±15.9 bpm (p=0.204).
Conclusion: Discontinuation of BB leads to clinical improvement and increased functional capacity at short term in patients with ATTR-CM.



**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.**
Nerea Mora-Ayestarán, Hospital Universitario Puerta de Hierro, Madrid, Spain

**Main Body of the Abstract**
**Background:** There is controversy regarding the usefulness of heart failure (HF) drugs in ATTR-CM. The aim of this study was to assess the clinical impact at short term of discontinuing beta-blockers (BB) in ATTR-CM.
**Methods:** This study was a prospective assessment of ATTR-CM patients who discontinued BB at their initial evaluation at Hospital Universitario Puerta de Hierro, Madrid, Spain. BB are systematically discontinued in our center unless patients have history of symptoms due to uncontrolled atrial fibrillation (AF). Patients underwent serial clinical assessment including NtproBNP, 6-minute walk test (6MWT), and Kansas City Cardiomyopathy Questionnaire (KCCQ) at initial visit and at 1 month.
**Results:** We studied 26 ATTR-CM patients who discontinued BB at their initial evaluation and did not have any other treatment modification. One patient required reintroduction of BB due to symptomatic uncontrolled AF and 3 subjects did not return for the 1-month follow-up visit despite they have not restarted BB afterwards. 22 patients (20 men, 77.5±5.3 years, 21 ATTRwt, 14 NYHA ≥II, LVEF 53.3±8.5% and 13 with AF) completed the evaluation. One month after BB withdrawal, 6MWT distance increased by 21±6 m (from 329.7±91.0 to 350.6±96.8; p<0.001), KCCQ increased by 9±3 points (66.5±26.4 to 75.4±23.5; p<0.001) while NTproBNP decreased (2842±2278 to 2258.86±1662 pg/mL; p<0.001). NYHA improved in 5/14 patients (35%) who had NYHA ≥II. Heart rate increased from 68.4±12.6 to 81.1±15.9 bpm (p=0.204).
**Conclusion:** Discontinuation of BB leads to clinical improvement and increased functional capacity at short term in patients with ATTR-CM.



Clinical impact of beta-blocker withdrawal in Transthyretin amyloid cardiomyopathy OC11 (#387)

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.