What are the echocardiogram (echo) signs of amyloid cardiomyopathy and hypertrophic cardiomyopathy in an adult patient with a history of hypertension, diabetes, or other cardiovascular risk factors presenting with heart failure symptoms?

Echocardiographic Signs of Cardiac Amyloidosis and Hypertrophic Cardiomyopathy

The most reliable echocardiographic features to distinguish cardiac amyloidosis from hypertrophic cardiomyopathy are: granular sparkling myocardial appearance and thickened heart valves for amyloidosis, versus systolic anterior motion of the mitral valve and asymmetric septal hypertrophy for HCM. 1, 2

Cardiac Amyloidosis - Key Echo Features

Wall Thickness and Chamber Characteristics

• Concentric left ventricular hypertrophy with symmetrically thickened walls, typically without cavity dilation 1
• Increased interatrial septum thickness (>6 mm) - highly specific for amyloidosis 1
• Thickened atrioventricular valve leaflets (mitral and tricuspid) 1
• Increased right ventricular free wall thickness - distinguishes amyloidosis from isolated HCM 1
• Biatrial enlargement despite relatively preserved ventricular cavity size 1

Myocardial Texture

• Granular or "sparkling" myocardial appearance - the most characteristic finding, representing amyloid infiltration 1, 3, 2
• Ground-glass texture of the myocardium 1

Functional Parameters

• Restrictive filling pattern with E/A ratio ≥2 and E-wave deceleration time ≤150 ms 1
• Mildly reduced ejection fraction (typically 40-50%) with restrictive physiology - contrasts with hyperdynamic function in HCM 1
• Severely reduced longitudinal strain affecting all segments globally, with relative apical sparing creating a "bulls-eye" pattern 1, 4
• Low QRS voltage on ECG relative to the degree of wall thickness on echo 2

Additional Features

• Mild to moderate pericardial effusion 1, 3
• Thickened papillary muscles 3
• Nodular thickening of the aortic valve 1

Hypertrophic Cardiomyopathy - Key Echo Features

Wall Thickness Patterns

• Maximal LV wall thickness ≥15 mm (or ≥13-14 mm in family members with confirmed HCM) measured anywhere in the left ventricle 1, 5
• Asymmetric septal hypertrophy - most common pattern involving basal anterior septum and anterior free wall 1
• Focal or segmental hypertrophy limited to 1-2 LV segments is possible 1
• Extreme wall thickness ≥30 mm indicates high sudden death risk 6

Dynamic Obstruction

• Systolic anterior motion (SAM) of the mitral valve with mitral-septal contact - highly specific for HCM 1, 2
• Left ventricular outflow tract obstruction with gradient ≥30 mmHg at rest or with provocation (Valsalva, standing, exercise) 1, 6
• Gradient ≥50 mmHg defines hemodynamically significant obstruction 1, 6

Systolic Function

• Normal or hyperdynamic ejection fraction (typically >65%) - contrasts with mildly reduced EF in amyloidosis 1, 2
• Reduced longitudinal strain specifically at sites of hypertrophy, with segmental rather than global pattern 1, 4
• Preserved radial function despite reduced longitudinal deformation 1

Diastolic Function

• Abnormal diastolic function with elevated E/e' ratio indicating elevated filling pressures 1
• Restrictive filling pattern (E/A ≥2) in advanced cases indicates poor prognosis 1

Structural Features

• Hypertrophied and apically displaced papillary muscles 1
• Elongated mitral valve leaflets 1
• Small or normal-sized left ventricular cavity 1

Critical Distinguishing Features

Favors Amyloidosis Over HCM

• Granular sparkling myocardium (sensitivity 28/29 patients when combined with other features) 2
• Thickened heart valves 1, 2
• Thickened interatrial septum 1
• Biventricular hypertrophy with RV free wall involvement 1
• Pericardial effusion 1, 2
• Low ECG voltage relative to wall thickness 2
• Global reduction in strain with apical sparing pattern 1, 4

Favors HCM Over Amyloidosis

• Systolic anterior motion of mitral valve 1, 2
• Asymmetric septal hypertrophy rather than concentric pattern 1, 2
• Large LV mass with hyperdynamic function 2
• High QRS voltage (sum of S in V1 + R in V5/V6 >35 mm) 2
• Segmental rather than global strain reduction 4

Common Pitfalls to Avoid

• Do not rely on wall thickness alone - both conditions can present with similar degrees of hypertrophy 1
• Apical hypertrophy may be missed on standard echocardiography; use contrast or CMR if suspected 1
• Coexisting hypertension occurs in 62% of HCM patients and does not exclude the diagnosis 7
• Normal ejection fraction does not exclude amyloidosis - look for restrictive physiology and reduced longitudinal strain 1, 8
• When the four strongest predictors (LV mass, thickened valves, granular myocardium, and SAM) are applied, diagnostic accuracy reaches 96% 2