What does a mitral valve E/A (Ejection/Acceleration) ratio of 0.64 indicate?

Mitral Valve E/A Ratio of 0.64: Interpretation and Clinical Significance

An E/A ratio of 0.64 indicates Grade I diastolic dysfunction (impaired relaxation pattern), characterized by delayed left ventricular relaxation with normal or low left atrial filling pressures. 1, 2

What This Ratio Means

• The E/A ratio of 0.64 falls well below the diagnostic threshold of ≤0.8 that defines Grade I diastolic dysfunction, particularly when accompanied by a peak E velocity ≤50 cm/sec 1, 2, 3

• This pattern reflects impaired myocardial relaxation as the primary abnormality, not elevated filling pressures or chamber remodeling 3

• Normal left ventricular filling pressures are expected with this E/A ratio, as Grade I dysfunction is characterized by an average E/e' ratio <8 and normal left atrial volume index (<34 mL/m²) 1, 3

Confirming the Diagnosis

To fully characterize Grade I diastolic dysfunction beyond just the E/A ratio, you should verify:

• Peak E velocity ≤50 cm/sec to confirm the impaired relaxation pattern 1, 2
• Average E/e' ratio <8 (typically with septal e' <7 cm/sec and lateral e' <10 cm/sec) to confirm normal filling pressures 1, 2, 3
• Normal left atrial volume index <34 mL/m² to exclude chronically elevated pressures 1, 3
• Tricuspid regurgitation velocity <2.8 m/sec to further confirm absence of elevated pressures 1, 3

Critical Clinical Context

A common pitfall is assuming all low E/A ratios indicate the same clinical scenario. The E/A ratio must be interpreted alongside other parameters:

• In patients with reduced ejection fraction, an E/A ratio <1 with other parameters may still indicate elevated filling pressures if the pattern is "pseudonormal" (E/A 0.8-2.0 with E/e' >14) 4, 3

• The Valsalva maneuver can unmask pseudonormalization: if the E/A ratio decreases by >0.5 during Valsalva, this suggests elevated filling pressures despite an apparently normal baseline ratio 4

• In patients with mitral annular calcification, the E/A ratio becomes MORE reliable than E/e' for estimating filling pressures, as E/e' shows only weak correlation (r=0.42) in this population 4, 5

What Grade I Diastolic Dysfunction Does NOT Mean

Grade I dysfunction does not involve chamber dilatation - the pathophysiology centers on impaired relaxation, not structural remodeling 3

• Left ventricular dimensions should be normal in isolated Grade I dysfunction 3
• If left atrial enlargement is present (volume index >34 mL/m²), this indicates at least Grade II dysfunction, not Grade I 3
• The presence of ventricular dilatation should prompt evaluation for alternative diagnoses such as dilated cardiomyopathy, significant valvular disease, or more advanced diastolic dysfunction 3

Management Implications

Address the underlying etiologies driving impaired relaxation:

• Control hypertension aggressively with ACE inhibitors or ARBs, which may directly improve ventricular relaxation and promote regression of hypertrophy 1
• Use beta-blockers to lower heart rate and increase diastolic filling period, particularly beneficial in patients with concomitant coronary artery disease 1
• Manage contributing factors including obesity, diabetes, and coronary artery disease 1

Monitoring Strategy

• Regular echocardiographic surveillance is necessary to detect progression to higher grades of diastolic dysfunction 1
• Consider diastolic stress testing if symptoms develop despite normal resting parameters 1
• Watch for indirect signs of progression: left atrial dilatation, development of restrictive filling pattern (E/A ≥2.0), or elevated E/e' ratio (>14) 3