What are the typical echocardiography (echo) findings in a patient with suspected cardiac amyloidosis?

Echocardiographic Findings in Cardiac Amyloidosis

Transthoracic echocardiography is the primary and most widely available diagnostic imaging tool for suspected cardiac amyloidosis, providing multiple "red flag" findings that should prompt further diagnostic workup. 1

Structural Abnormalities

Left Ventricular Changes

• Increased LV wall thickness (≥12 mm), often with a small LV cavity size, is the hallmark structural finding 1, 2
• The myocardium demonstrates a characteristic diffuse hyper-refractile "granular sparkling" appearance on 2D imaging, reflecting amyloid infiltration 1, 3
• Normal or small LV cavity dimensions despite significant wall thickening 4

Atrial and Valvular Findings

• Biatrial enlargement is commonly present and disproportionate to the degree of ventricular dysfunction 1
• Thickened cardiac valves without significant stenosis 1
• Increased atrial septal thickness 1
• Pericardial effusion may be present 1

Right Ventricular Involvement

• Thickened right ventricular myocardium 3
• Elevated right ventricular systolic pressure 1

Functional Abnormalities

Diastolic Dysfunction

• Restrictive transmitral Doppler filling pattern is characteristic, reflecting severe diastolic dysfunction 1, 4
• Grade ≥2 diastolic dysfunction on Doppler assessment 2

Systolic Dysfunction Patterns

• Reduced ventricular longitudinal strain with a characteristic apical sparing pattern 1, 2
• Apical-to-basal strain ratio >2.1 is highly suggestive of cardiac amyloidosis 1, 2
• LV ejection fraction-to-strain ratio >4 1
• Systolic dysfunction typically occurs only in late-stage disease, despite earlier diastolic abnormalities 4

Critical Diagnostic Clue: Voltage-Mass Mismatch

The combination of low QRS voltage on ECG with increased LV wall thickness on echocardiography (>12 mm) is particularly useful for raising clinical suspicion of cardiac amyloidosis. 1, 2 This "voltage-to-mass discordance" represents a key diagnostic red flag that should prompt immediate further evaluation. 1

Advanced Echocardiographic Techniques

Speckle-Tracking Analysis

• Multiple international guidelines (CCS/CHFS, JCS, DGK) recommend using speckle-tracking analysis as part of comprehensive echocardiographic evaluation 1
• Provides more accurate assessment of LV function than conventional measures 4
• Can detect subtle changes in systolic and diastolic function not apparent on standard Doppler 4

Tissue Doppler Imaging

• Detects subtle changes in both systolic and diastolic LV function that cannot be identified by conventional Doppler flow measurements 4
• Provides important prognostic information beyond standard echocardiographic parameters 4

Standardized Diagnostic Scoring

The European Society of Cardiology uniquely proposes the IWT (Integrated Wall Thickness) echocardiographic score, where values ≥8 can be diagnostic of ATTR cardiac amyloidosis when combined with positive bone scintigraphy (Perugini score 2-3), absence of monoclonal protein, and peripheral tissue biopsy showing ATTR amyloid. 1 This represents the first attempt to standardize echocardiographic evaluation in suspected cardiac amyloidosis. 1

Important Limitations

Cannot Differentiate Amyloid Subtypes

• Echocardiography cannot distinguish AL (light chain) from ATTR (transthyretin) cardiac amyloidosis, as emphasized by the American Heart Association 1
• Further testing with monoclonal protein screening and/or nuclear imaging is required for subtype determination 1

Distinguishing from Other Cardiomyopathies

• While echocardiography is useful to distinguish cardiac amyloidosis from other cardiomyopathies with hypertrophic phenotype, definitive diagnosis requires additional testing 1
• The granular sparkling appearance, while classic, is not universally present and has limited sensitivity 3

Clinical Integration

When echocardiography shows these suggestive findings, proceed immediately with:

• Monoclonal protein screening (serum/urine immunofixation, serum free light chains) 1, 2
• NT-proBNP and troponin measurement (normal levels virtually exclude cardiac amyloidosis) 1
• Nuclear imaging with bone tracers (99mTc-PYP/DPD/HMDP) for ATTR diagnosis 1, 2
• Cardiac MRI for tissue characterization if echocardiography is equivocal 2

The combination of characteristic echocardiographic findings with appropriate biomarkers and nuclear imaging can establish the diagnosis non-invasively in many cases, avoiding the need for endomyocardial biopsy. 1, 3