# Endomyocardial Biopsy Revisited: Diagnostic Value and Expanding Roles in Cardiac Amyloidosis

## TL;DR

This paper reviews the role of endomyocardial biopsy in diagnosing and managing cardiac amyloidosis, emphasizing its value in cases where non-invasive methods fall short.

## Contribution

The paper highlights the evolving role of endomyocardial biopsy in phenotyping and assessing treatment response in cardiac amyloidosis.

## Key findings

- Endomyocardial biopsy provides the highest diagnostic accuracy for cardiac amyloidosis in selected cases.
- Higher amyloid load and inflammatory infiltration correlate with adverse outcomes.
- EMB may help assess amyloid clearance and treatment response in new therapies.

## Abstract

Cardiac amyloidosis (CA) results from myocardial infiltration by misfolded amyloidogenic proteins and represents a heterogeneous group of diseases with distinct prognostic and therapeutic implications. While transthyretin amyloidosis (ATTR) and immunoglobulin light-chain amyloidosis (AL) account for the majority of clinically relevant cases, several rarer amyloid subtypes with cardiac involvement have been described.This review focusses on the role of EMB in CA, highlights its diagnostic andprognostic value, discusses procedural considerations, and outlines emergingperspectives, including its potential role in phenotyping amyloid clearance andassessing treatment response in the era of novel disease-modifying therapies.

Over the past decade, diagnostic algorithms have shifted from predominantly invasive approach toward non-invasive imaging, particularly bone scintigraphy, which enables reliable diagnosis of ATTR in selected patients. However, important limitations remain. Non-invasive strategies may be insufficient in early disease stages, in the presence of monoclonal gammopathy, or in rare amyloid subtypes, where definitive amyloid typing is required. In these situations, EMB continues to play a central role. Additionally, EMB allows detailed assessment of amyloid burden and myocardial. Recent studies further demonstrate that beyond its diagnostic value, EMB also offers prognostic information, as higher amyloid load and inflammatory infiltration have been associated with adverse outcomes. Procedural risks appear acceptable when EMB is performed in experienced centers, although data on optimal biopsy strategies remain limited. In the era of emerging disease-modifying therapies, EMB may also gain an increasing relevance for disease phenotyping, assessment of amyloid clearance, and evaluation of treatment response.

Despite major advances in non-invasive imaging, EMB provides the highest diagnostic accuracy in selected patients with suspected CA, enabling definitive amyloid typingand comprehensive myocardial tissue characterization that may contribute to refined disease phenotyping and the assessment of treatment response.