What are the key imaging signs and management strategies for Heart Failure with preserved Ejection Fraction (HFpEF)?

Key Imaging Signs of Heart Failure with Preserved Ejection Fraction (HFpEF)

Transthoracic echocardiography (TTE) is the primary imaging modality for diagnosing HFpEF, with specific structural and functional abnormalities serving as diagnostic markers for this condition. 1, 2

Definition and Diagnostic Criteria

HFpEF is defined by:

• Presence of heart failure signs and symptoms
• Left ventricular ejection fraction (LVEF) ≥50%
• Evidence of cardiac structural/functional abnormalities leading to elevated filling pressures 1, 2

Key Echocardiographic Findings in HFpEF

Structural Abnormalities

• Left atrial enlargement: Left atrial volume index ≥34 mL/m² 2
• Left ventricular hypertrophy: LV mass index ≥95 g/m² (women) or ≥115 g/m² (men) 2
• Normal or near-normal LVEF (≥50%) 1, 2
• Increased LV wall thickness 3

Functional Abnormalities

• Diastolic dysfunction indicated by:
  • Average E/e' ratio ≥15 (key marker of elevated LV filling pressures) 2
  • Septal e' velocity <7 cm/s or lateral e' <10 cm/s (reduced myocardial relaxation) 2
  • Abnormal mitral inflow patterns 3
• Elevated pulmonary pressures: Tricuspid regurgitation velocity >2.8 m/s (RVSP ≥35 mmHg) 2
• Reduced diastolic wall strain of the posterior wall (DWS PW) 4
• Abnormal vortex formation time (VFT) 4

Advanced Imaging Techniques

Exercise Echocardiography

• Particularly valuable when resting echocardiography is inconclusive
• Exercise-induced elevation in E/e' ratio (>15) suggests HFpEF 2
• Exertional pulmonary hypertension 3

Cardiac Magnetic Resonance (CMR)

• Useful when echocardiographic findings are inconclusive or to identify specific etiologies
• Provides accurate assessment of:
  • Chamber volumes
  • LV mass
  • Tissue characterization (fibrosis, infiltration)
  • Pericardial abnormalities 1, 3

Newer Echocardiographic Parameters

• Speckle-tracking echocardiography: Detects subtle systolic dysfunction despite normal LVEF
  • Reduced global longitudinal strain despite preserved LVEF 3
• 3D echocardiography: More accurate assessment of LV volumes and mass 3

Imaging Approach for HFpEF Diagnosis

1. Initial imaging: Chest radiography and resting TTE 1
2. If inconclusive: Consider exercise echocardiography to unmask diastolic dysfunction 2
3. For further characterization: CMR for tissue characterization and to rule out specific etiologies 1, 3

Diagnostic Pitfalls to Avoid

• Obesity effect: Natriuretic peptide levels may be lower in obese patients with HFpEF 2
• Single parameter limitation: No single echocardiographic parameter is sufficient; an integrated approach is necessary 2
• HFpEF mimics: Important to rule out conditions that can present similarly:
  • Cardiac amyloidosis
  • Hypertrophic cardiomyopathy
  • Constrictive pericarditis
  • High-output heart failure 1

Management Implications Based on Imaging

• Diuretics for congestion when imaging shows elevated filling pressures 5
• SGLT2 inhibitors (dapagliflozin, empagliflozin) have shown benefit in reducing HF hospitalizations 5
• Exercise training and weight loss for improved functional capacity 5
• Treatment of specific comorbidities identified through imaging 1

By systematically evaluating these imaging parameters, clinicians can more accurately diagnose HFpEF and distinguish it from other causes of dyspnea, leading to appropriate management strategies that improve outcomes.