What are the typical echocardiography (ECHO) findings in patients with Heart Failure with preserved Ejection Fraction (HFpEF)?

Echocardiographic Findings in HFpEF

In HFpEF, echocardiography must demonstrate preserved or only mildly reduced LVEF (≥45-50%) combined with evidence of diastolic dysfunction, structural cardiac abnormalities, or elevated filling pressures to confirm the diagnosis. 1

Essential Diagnostic Criteria

The diagnosis of HFpEF requires three mandatory echocardiographic conditions to be satisfied 1:

1. Preserved LV systolic function: LVEF ≥45-50% 1
2. Evidence of diastolic dysfunction: Abnormal LV relaxation or diastolic stiffness 1
3. Structural or functional cardiac abnormalities (detailed below) 1

Key Structural Findings

According to the European Society of Cardiology guidelines, five core structural parameters should be assessed 1:

• Left atrial volume index (LAVI): Typically elevated, reflecting chronic elevation of filling pressures 1
• Left ventricular mass index (LVMI): Often increased, indicating LV hypertrophy 1
• Left ventricular hypertrophy: Common finding representing structural remodeling 2
• Tricuspid regurgitation velocity (TRV): Elevated pulmonary artery pressure >35 mmHg is frequently present 1, 2

Diastolic Function Parameters

Mitral Inflow Patterns (E/A Ratio)

Three distinct abnormal filling patterns are recognized in sinus rhythm 1:

1. Impaired relaxation pattern (E/A <1): Decreased peak E-velocity with compensatory increase in A-velocity, indicating early diastolic dysfunction with normal or low filling pressures 1

2. Restrictive filling pattern (E/A >2, deceleration time 115-150 ms): Elevated peak E-velocity with short deceleration time, indicating high filling pressures and advanced disease 1

3. Pseudonormal pattern (E/A >1): Intermediate pattern that appears normal but masks elevated filling pressures; can be unmasked with Valsalva maneuver 1

Tissue Doppler Imaging (E/e' Ratio)

E/e' is the most established and prognostically validated parameter in HFpEF, though it has only modest correlation with invasive filling pressures (r=0.56). 1

• E/e' >15: Indicates high filling pressures 1
• E/e' <8: Suggests low filling pressures 1
• E/e' 8-15: Inconclusive, requires integration with other parameters 1

Critical caveat: E/e' should never be used in isolation to diagnose HFpEF, as it has poor sensitivity (36-64%) despite reasonable specificity (73-89%) for elevated filling pressures. 1 The 2018 systematic review demonstrated that E/e' has only modest prognostic value (HR 1.05 per unit increase for mortality/cardiovascular hospitalization). 1

Myocardial Tissue Velocity (e')

• Reduced e' velocity (<8-9 cm/s septal, <10 cm/s lateral): Indicates impaired LV relaxation 1
• Measured at septal and/or lateral mitral annulus 1

Additional Doppler Parameters

The ESC guidelines detail multiple supplementary Doppler indices 1:

• Pulmonary vein flow: S wave >D wave suggests low filling pressures; reversed pattern indicates elevated pressures 1
• (A mitral - A pulmonary) duration: <30 ms indicates high filling pressures; >30 ms suggests normal pressures 1
• Flow propagation velocity (Vp): <45 cm/s indicates slow relaxation 1
• E/Vp ratio: >2.5 suggests high filling pressures; <2 indicates low pressures 1

Advanced Echocardiographic Techniques

Speckle-Tracking Echocardiography

Global longitudinal strain (GLS) is reduced in HFpEF patients compared to controls, even with preserved LVEF, providing sensitive detection of subclinical systolic dysfunction. 1, 3

• Patients with HFpEF demonstrate lower longitudinal and circumferential strains compared to hypertensive heart disease patients 1
• During exercise, LV longitudinal strain is significantly reduced in HFpEF (-17±5%) versus controls (-22±4%) 4
• GLS provides prognostic information and aids in phenotyping HFpEF 3

Exercise Stress Echocardiography

Exercise stress echo is valuable for diagnosing HFpEF in patients with unexplained dyspnea who lack overt congestion at rest (approximately 35% of HFpEF patients). 5, 6, 4

During submaximal exercise testing in HFpEF patients 4:

• LV longitudinal diastolic relaxation (e') is reduced: 9±2 cm/s versus 15±4 cm/s in controls
• RV longitudinal systolic function (RV s') is impaired: 14±3 cm/s versus 18±1 cm/s in controls
• LV afterload (arterial elastance) correlates with decreased LV longitudinal strain (R=0.51)

Integrated Assessment Approach

No single echocardiographic parameter can reliably diagnose HFpEF; an integrated assessment of multiple markers is mandatory. 1 The guidelines emphasize combining:

• Structural parameters (LAVI, LVMI) 1
• Diastolic function indices (E/A, E/e', e') 1
• Hemodynamic markers (TRV, pulmonary pressures) 1, 2
• Clinical characteristics and natriuretic peptides 5, 6

Common Pitfalls to Avoid

• Do not rely solely on E/e' for diagnosis, as it has limited diagnostic accuracy in HFpEF populations 1
• Recognize pseudonormal patterns: Use Valsalva maneuver to unmask elevated filling pressures when E/A appears normal 1
• Consider exercise testing when resting echo is inconclusive, particularly in patients with unexplained dyspnea 5, 4
• Use contrast agents only when ≥2 contiguous LV segments are poorly visualized, not routinely 1
• Remember that HFpEF and diastolic dysfunction are not identical: HFpEF requires clinical symptoms plus objective evidence 1