How do you differentiate heart failure with preserved systolic function from other cardiomyopathies on echocardiography (echo)?

Differentiating HFpEF from Other Cardiomyopathies on Echocardiography

The key to distinguishing heart failure with preserved ejection fraction (HFpEF) from other cardiomyopathies on echo is systematically excluding specific mimics—particularly hypertrophic cardiomyopathy, cardiac amyloidosis, and restrictive cardiomyopathies—while confirming the integrated presence of preserved LVEF (≥45-50%), diastolic dysfunction markers, and structural abnormalities without the distinctive features of these alternative diagnoses. 1, 2

Step 1: Confirm Preserved Systolic Function

• Measure LVEF ≥45-50% using Simpson's biplane method as the foundational criterion 2, 3
• Assess for LV global longitudinal strain (GLS), which may be impaired even with preserved LVEF in HFpEF (typically >-18% indicates abnormal longitudinal function) 3
• Document mitral annular systolic velocity (s') and mitral annular plane systolic excursion (MAPSE), which are often reduced in HFpEF despite preserved LVEF 3

Step 2: Assess Diastolic Function Parameters

The diagnosis requires an integrated assessment of multiple parameters—no single measure is sufficient 2, 3:

Primary Diastolic Markers:

• E/e' ratio: >15 indicates elevated filling pressures; <8 suggests normal pressures; 8-15 requires additional parameters 2, 3
• Septal e' <7 cm/sec or lateral e' <10 cm/sec indicates impaired relaxation 3
• E/A ratio patterns in sinus rhythm:
  • E/A ≤0.8 with E velocity ≤50 cm/sec = Grade I diastolic dysfunction (impaired relaxation) 3
  • E/A 0.8-2.0 = requires additional parameters 3
  • E/A ≥2 with deceleration time <160 ms = restrictive pattern (Grade III) 3

Supporting Parameters:

• Tricuspid regurgitation velocity (TRV) >2.8 m/sec supports elevated LV filling pressures 3, 2
• Pulmonary vein S/D ratio <1 suggests elevated filling pressures 3, 2
• Isovolumic relaxation time (IVRT) >105 ms indicates diastolic dysfunction 4

Step 3: Document Structural Abnormalities

Five core structural parameters must be assessed 2:

• Left atrial volume index (LAVI) >34 mL/m² reflects chronic elevation of filling pressures 2, 3
• LV mass index (LVMI): >115 g/m² in men, >95 g/m² in women indicates LV hypertrophy 2, 3
• LV wall thickness: increased in 75% of HFpEF cases 4
• Estimated pulmonary artery systolic pressure (sPAP) from TR jet plus RA pressure 2, 3
• Inferior vena cava (IVC) diameter and respiratory variation for RA pressure estimation 3

Step 4: Systematically Exclude HFpEF Mimics

This is the critical diagnostic pitfall that distinguishes HFpEF from other cardiomyopathies 1:

Hypertrophic Cardiomyopathy (HCM):

• Look for asymmetric septal hypertrophy (septal/posterior wall thickness ratio >1.3) 3
• Assess for systolic anterior motion (SAM) of the mitral valve 3
• Measure LV outflow tract gradient with continuous wave Doppler 3
• HCM shows marked hypertrophy (often >15 mm) in a non-hypertensive distribution pattern 1

Cardiac Amyloidosis:

• Identify "sparkling" or granular myocardial texture on 2D imaging 1
• Look for biatrial enlargement disproportionate to LV dysfunction 1
• Assess for thickened interatrial septum (>6 mm) 1
• Measure reduced GLS with apical sparing (apical-to-basal strain ratio >1) 1
• Document small pericardial effusion often present 1
• Note restrictive filling pattern with very short deceleration time 1

Restrictive Cardiomyopathies (Sarcoidosis, Hemochromatosis, Fabry):

• Assess for regional wall motion abnormalities suggesting infiltrative disease 1
• Look for basal inferolateral thinning (characteristic of sarcoidosis) 1
• Document any valvular thickening (seen in Fabry disease) 1

Pericardial Disease (Constrictive Pericarditis):

• Measure pericardial thickness >3-4 mm 3
• Assess for respiratory variation in mitral inflow velocities >25% 3
• Look for septal bounce and dilated IVC with minimal respiratory variation 3

Step 5: Apply Diagnostic Algorithm

If 2 or more of the following 3 parameters are abnormal, elevated LAP and Grade II diastolic dysfunction are confirmed 3:

1. Average E/e' >14
2. TR velocity >2.8 m/sec
3. LA volume index >34 mL/m²

Common Pitfall: A normal LA volume does not exclude diastolic dysfunction in acute presentations or early-stage disease 3. In these cases, rely more heavily on E/e' ratio and TR velocity 3.

Key Distinguishing Features Summary

HFpEF shows:

• Preserved LVEF with impaired GLS 3
• Elevated E/e' ratio (typically 13-15) 3, 2
• LA enlargement proportionate to chronicity 2
• Concentric LV hypertrophy related to hypertension 4, 5
• No distinctive infiltrative or genetic cardiomyopathy features 1

Other cardiomyopathies show:

• HCM: Marked asymmetric hypertrophy, LVOT obstruction, SAM 3, 1
• Amyloidosis: Granular texture, biatrial enlargement, apical sparing on strain, very restrictive pattern 1
• Restrictive: Regional abnormalities, specific infiltrative patterns 1
• Constrictive pericarditis: Pericardial thickening, respiratory variation, septal bounce 3

The integrated assessment approach is mandatory because E/e' alone has only modest correlation with invasive filling pressures (r=0.56) in HFpEF populations 3. Combining structural parameters (LAVI, LVMI), diastolic indices (E/A, E/e', e'), and hemodynamic markers (TRV, sPAP) provides the diagnostic accuracy needed 2, 3.