**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.**
Belen Peiro-Aventin.
Heart Failure and Inherited Cardiac Diseases Unit, Department of Cardiology, Puerta de Hierro University Hospital.
Majadahonda (Madrid), Spain.

**Main Body of the Abstract**
Background: Asymptomatic carriers of pathogenic TTR variants represent a group of patients at risk for development of ATTR cardiomyopathy. Early identification of cardiac amyloid is important to guide timely initiation of disease-modifying therapy. We sought to identify ECG changes associated with development of ATTR amyloid cardiomyopathy among TTR mutation carriers.
Methods: We retrospectively studied evolution of ECG findings in 40 TTR mutation carriers (58% women, 51±10 years, 35% with Val50Met) without cardiac amyloid at initial evaluation, who had undergone ≥2 scintigraphy studies during follow-up. Changes in ECG parameters were compared between subjects who developed cardiac amyloid (on the basis of abnormal DPD tracer uptake) and those who did not.
Results: After a median follow-up of 2.6 years(IQR 2-4.7), 6 individuals (4 male, 49±11 years, 1 Val50Met) developed cardiac amyloid (4 Perugini grade 1; one grade 2 and one grade 3). No differences were observed in the evolution of PR interval, QRS duration, or limb lead QRS voltages between patients who did and did not develop cardiac amyloid. However, a significant reduction in mean QRS voltage was observed in V3[-2.5 (-8 to -1) vs. 0 (-2 to 2) mVx10-1; p=0.02] and in the sum of all precordial leads[-11 (-20 to 0) vs. 1 (-8 to 3) mVx10-1; p=0.04] in patients who developed cardiac amyloid during follow-up compared to those who did not.
Conclusions: Decrease in overall QRS voltage of precordial leads on ECG warrants further study as a potential early indicator of development of cardiac amyloid in asymptomatic TTR mutation carriers.



**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.**
Belen Peiro-Aventin.
Heart Failure and Inherited Cardiac Diseases Unit, Department of Cardiology, Puerta de Hierro University Hospital.
Majadahonda (Madrid), Spain.

**Main Body of the Abstract**
**Background:** Asymptomatic carriers of pathogenic TTR variants represent a group of patients at risk for development of ATTR cardiomyopathy. Early identification of cardiac amyloid is important to guide timely initiation of disease-modifying therapy. We sought to identify ECG changes associated with development of ATTR amyloid cardiomyopathy among _TTR_ mutation carriers.
**Methods**: We retrospectively studied evolution of ECG findings in 40 _TTR_ mutation carriers (58% women, 51±10 years, 35% with Val50Met) without cardiac amyloid at initial evaluation, who had undergone ≥2 scintigraphy studies during follow-up. Changes in ECG parameters were compared between subjects who developed cardiac amyloid (on the basis of abnormal DPD tracer uptake) and those who did not.
**Results:** After a median follow-up of 2.6 years(IQR 2-4.7), 6 individuals (4 male, 49±11 years, 1 Val50Met) developed cardiac amyloid (4 Perugini grade 1; one grade 2 and one grade 3). No differences were observed in the evolution of PR interval, QRS duration, or limb lead QRS voltages between patients who did and did not develop cardiac amyloid. However, a significant reduction in mean QRS voltage was observed in V3[-2.5 (-8 to -1) vs. 0 (-2 to 2) mVx10^-1^; p=0.02] and in the sum of all precordial leads[-11 (-20 to 0) vs. 1 (-8 to 3) mVx10^-1^; p=0.04] in patients who developed cardiac amyloid during follow-up compared to those who did not.
**Conclusions**: Decrease in overall QRS voltage of precordial leads on ECG warrants further study as a potential early indicator of development of cardiac amyloid in asymptomatic _TTR_ mutation carriers.



ECG changes in asymptomatic ATTRv carriers developing ATTR cardiomyopathy. PB39 (#385)

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.