The Four Stages of Diastolic Dysfunction
Diastolic dysfunction is classified into three grades (I, II, and III) based on the 2016 ASE/EACVI guidelines, not four stages—this represents a progressive spectrum from impaired relaxation with normal filling pressures to restrictive filling with elevated pressures. 1
Grade I: Impaired Relaxation with Normal Left Atrial Pressure
Grade I diastolic dysfunction is characterized by impaired relaxation with normal left atrial pressure (LAP). 1
- Mitral inflow pattern: E/A ratio ≤0.8 with peak E velocity ≤50 cm/sec 1
- Tissue Doppler: Reduced mitral annular e′ velocity (septal e′ <7 cm/sec, lateral e′ <10 cm/sec) 1
- Left atrial volume index: <34 mL/m² (normal) 1
- Average E/e′ ratio: <14 (normal) 1
- TR jet velocity: <2.8 m/sec (normal) 1
Diagnostic criteria: Less than 50% of the available echocardiographic parameters (from the four recommended variables above) meet cutoff values for elevated LAP. 1
This grade represents the earliest stage where the left ventricle has impaired relaxation but compensates through increased atrial contraction, maintaining normal filling pressures. 1, 2
Grade II: Pseudonormalization (Moderate Dysfunction)
Grade II diastolic dysfunction represents pseudonormalization where impaired relaxation is masked by elevated left atrial pressure. 1
- Mitral inflow pattern: E/A ratio appears normal (0.8-2.0) or the E/A ratio is ≤0.8 but peak E velocity is >50 cm/sec 1
- Elevated LAP indicators: More than 50% of the available parameters meet cutoff values 1
Critical pitfall: The mitral inflow pattern may appear deceptively normal because elevated left atrial pressure "normalizes" the E/A ratio, which is why tissue Doppler (showing reduced e′ velocity) and other parameters are essential to unmask this stage. 1, 2
This stage indicates progression where the left ventricle requires higher filling pressures to achieve adequate diastolic filling. 1
Grade III: Restrictive Filling (Severe Dysfunction)
Grade III diastolic dysfunction is defined by a restrictive filling pattern with markedly elevated left atrial pressure and severely impaired compliance. 1
- Mitral inflow pattern: E/A ratio ≥2 with restrictive physiology 1
- Deceleration time: <160 msec (typically <150 msec) 1
- Tissue Doppler: Severely reduced mitral annular e′ velocity (septal <7 cm/sec, lateral <10 cm/sec) 1
- IVRT: <50 msec 1
- LA volume index: Markedly increased (often >50 mL/m²) 1
**Exception for young patients (<40 years):** An E/A ratio >2 may be normal, so other signs of diastolic dysfunction must be present before diagnosing Grade III. 1
Prognostic significance: Grade III diastolic dysfunction is associated with poor outcomes and high mortality, particularly in restrictive cardiomyopathy. 1
Special Considerations for Your Patient Context
Given your patient has impaired renal function, mild sleep apnea, and LVEF 55-60%:
- Renal function: Careful interpretation of E/e′ ratio is needed as volume status affects filling pressures; avoid overdiuresis which can worsen diastolic filling. 3
- Sleep apnea: Even mild sleep apnea contributes to hypertension and atrial arrhythmias, potentially accelerating diastolic dysfunction progression—treatment is warranted. 3
- Preserved LVEF (55-60%): This patient has preserved systolic function, so any heart failure symptoms would be classified as HFpEF if diastolic dysfunction is present. 1, 3
Important Diagnostic Caveats
- Indeterminate cases: When exactly 50% of parameters meet cutoff values (e.g., 2 out of 4 available), the study is inconclusive for estimating LAP—additional testing or clinical correlation is required. 1
- Recent cardioversion: Use deceleration time rather than E/A ratio due to atrial stunning causing falsely elevated E/A ratios. 1
- Atrial fibrillation: Standard grading algorithms do not apply; focus on E/e′ ratio, LA volume, and TR velocity. 1
- Mitral valve disease: Grading is unreliable with more than moderate mitral regurgitation or stenosis. 1