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Notes on How To Quantify the Diastolic Function of the Heart

 

Study for the Examination of Special Competence in Critical Care Echocardiography, (CCEeXAM®)

 

How is Grade II diastolic dysfunction diagnosed when the E/A ratio is normal?

  • When E/A is between 0.8 and 2.0, it’s not enough to determine grade II diastolic dysfunction.

  • You need at least 2 of these 3 findings:

    • E/e′ ratio >14

    • Left atrial volume index (LAVI) >34 mL/m²

    • Tricuspid regurgitation (TR) jet velocity >2.8 m/s

  • Meeting two or more means elevated left atrial pressure and grade II dysfunction.

 

What does a high E/A ratio (≥2) with reduced ejection fraction indicate?

  • An E/A ratio of 2.59 suggests a restrictive filling pattern.

  • In the context of reduced EF, this means Grade III diastolic dysfunction.

  • Indicates very elevated left atrial pressure.

 

How do you assess diastolic function in a patient with normal systolic function?

  • Use four criteria:

    • E/e′ >14

    • LAVI >34 mL/m²

    • TR velocity >2.8 m/s

    • Septal e′ <7 cm/s or lateral e′ <10 cm/s

  • If fewer than 2 of these are abnormal → normal diastolic function.

  • If 2 are abnormal → indeterminate.

  • If 3 or more are abnormal → diastolic dysfunction is present.

 

How do you assess diastolic function in atrial fibrillation?

  • Atrial contraction is lost, so E/A ratio can't be used.

  • Rely on other indicators:

    • Mitral deceleration time (DT) <160 ms

    • E/e′ ratio >11

    • IVRT <65 ms

    • Peak acceleration rate of mitral E >1900 cm/s²

 

What does a deceleration time <160 ms mean in atrial fibrillation?

  • Suggests elevated LV filling pressure.

  • Indicates diastolic dysfunction even in absence of a visible A-wave.

 

What if only limited diastolic parameters are available?

  • If only 2 criteria are available and just one is abnormal, you can still make a diagnosis.

  • In a patient with normal EF, if TR velocity is high and e′ is low → consistent with Grade I diastolic dysfunction.

 

How is moderate aortic stenosis defined?

  • Valve area between 1.0–1.5 cm²

  • Peak velocity 3.0–4.0 m/s

  • For example: valve area of 1.41 cm² and max velocity of 3.5 m/s = moderate AS.

 

How is aortic regurgitation severity assessed with pressure half-time?

  • Use the Bernoulli equation to calculate pressure from velocity.

  • Pressure half-time (PHT) <200 ms = severe AR.

  • Example: PHT of 180 ms supports severe aortic regurgitation.

 

How is mitral stenosis severity assessed with pressure half-time?

  • PHT >220 ms is consistent with severe mitral stenosis.

  • Example: PHT of 240 ms = severe MS.

 

How is pulmonary artery systolic pressure (PASP) calculated?

  • PASP = Right atrial pressure + 4 × (TR velocity)²

  • If TR jet is 4.8 m/s and RA pressure is 15 mm Hg:

    • 4 × 4.8² = 92

    • 15 + 92 = 107 mm Hg PASP

 

How is pulmonary artery diastolic pressure calculated?

  • Use end-diastolic velocity of pulmonary regurgitation.

  • PADP = CVP + 4 × (velocity)²

  • If CVP is 8 mm Hg and velocity is 2 m/s:

    • 4 × 2² = 16

    • 8 + 16 = 24 mm Hg

 

How is paravalvular leak (PVL) graded after TAVR?

  • Based on percentage of valve circumference involved:

    • <10% = mild

    • 10–30% = moderate

    • 30% = severe

  • Aliasing outside the valve ring during diastole suggests PVL.

 

How do you calculate stroke volume across the aortic valve?

  • Use LVOT diameter and VTI:

    • SV = π × (radius)² × VTI

    • Example: SV = 58 mL

 

How do you calculate stroke volume across the mitral valve?

  • Use mitral annular diameter and VTI:

    • SV = π × (radius)² × VTI

    • Example: SV = 183 mL

 

How is mitral regurgitant volume calculated?

  • Regurgitant volume = SV (mitral) − SV (aortic)

  • Example: 183 mL − 58 mL = 125 mL

 

How is mitral regurgitant fraction calculated?

  • Regurgitant fraction = Regurgitant Volume / SV (mitral)

  • Example: 125 / 183 = 68%

  • 50% = severe MR

 

How is effective regurgitant orifice area (EROA) calculated?

  • EROA = Regurgitant volume / VTI of MR jet

  • Example: 125 / 170 = 0.74 cm²

  • 0.4 cm² = severe MR

 

How is aortic valve area calculated using the continuity equation?

  • AVA = (CSA of LVOT × velocity at LVOT) / velocity at AV

  • Example gives 0.68 cm² → severe AS

 

What if the AVA is severe but gradients are only moderate?

  • This mismatch suggests “low-flow aortic stenosis.”

  • EF is low → less flow → lower velocities and gradients.

  • Valve still severely stenotic based on area.

 

Why is there mismatch between AVA and gradients?

  • Low EF leads to reduced stroke volume and low transvalvular flow.

  • This falsely lowers the peak velocity and pressure gradient.

  • AVA remains small, showing true severity.

 

How is aortic regurgitation severity assessed using cardiac output?

  • Compare forward stroke volume (LVOT) and total stroke volume (RVOT).

  • Regurgitant volume = total − forward

  • If regurgitant volume <30 mL and regurgitant fraction <30%, it’s mild AR.