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Notes on Left Ventricular Systolic Function

 

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

 

What phase of the cardiac cycle follows isovolumic contraction?

  •  After isovolumic contraction, the next phase is systolic ejection.
  •  This is when the left ventricle ejects blood through the aortic valve into the aorta.
  •   In Doppler of transmitral inflow:
    •  E wave = early filling
    •  A wave = atrial contraction
    •  Isovolumic contraction comes after A wave
    •  Systolic ejection is the flow phase after this
 

 

What does isovolumic contraction mean?

  •  The left ventricle is contracting, but no valves are open yet.
  •  Both mitral and aortic valves are closed.
  •  Pressure builds in the ventricle until it exceeds aortic pressure.
  •  Corresponds with the QRS complex on ECG.
 

 

Where should we measure the left ventricular end-diastolic diameter?

  •  Use the parasternal long-axis view.
  •  Measure perpendicular to the long axis of the ventricle.
  •  Position calipers at or just below the mitral valve leaflet tips.
  •  M-mode gives better resolution but may misalign with the long axis.
  •   EPSS (E-point septal separation) is also measured here:
    •  EPSS > 7 mm → likely EF < 50%
    •  Not reliable in AR, MS, or inferior wall abnormalities
 

 

How do you diagnose concentric hypertrophy?

  •  Wall thickness is increased, especially posterior wall.
  •  Normal thickness = 0.6 to 0.9 cm
  •   Use Relative Wall Thickness (RWT):
    •  Formula: (2 × posterior wall thickness) ÷ end-diastolic diameter
    •  RWT > 0.42 = concentric hypertrophy
 

 

How do you diagnose eccentric hypertrophy?

  •  LV mass is elevated, and chamber is dilated.
  •  RWT ≤ 0.42 indicates eccentric hypertrophy.
  •  Seen when the wall is thick, but the cavity is also enlarged.
 

 

How do you determine if systolic function is reduced using fractional shortening?

  •  Use this formula:
    (LVEDD − LVESD) / LVEDD
  •   Values:
    •  ≥25% = normal
    •  <25% = reduced
  •   Best when:
    •  No wall motion issues
    •  No conduction delays
    •  Normal LV geometry
  •  Example: FS of 12.7% = reduced function
 

 

What is an advantage of 2D echo over M-mode in LV assessment?

  •  2D ensures measurements are aligned with the LV axis.
  •  M-mode may cut obliquely, leading to errors.
  •  M-mode has better resolution but may miss axis alignment.
 

 

Why can a single apical four-chamber view overestimate LV function?

  •  This view shows only anterolateral and inferoseptal walls.
  •  Infarcts in anterior or inferior walls may be missed.
  •  Can falsely suggest preserved function in MI.
 

 

Which papillary muscle is most vulnerable to rupture in MI?

  •  Posteromedial papillary muscle.
  •  Supplied by RCA only → vulnerable to ischemia.
  •  Anterolateral muscle has dual supply (LAD + LCx) → more protected.
 

 

Which view allows you to see the mid-anterior wall?

  •  Apical two-chamber view.
  •  Also shows the inferior wall.
  •  Doesn’t include the right ventricle.
 

 

What coronary artery supplies the mid-inferior wall?

  •  Right coronary artery (RCA).
  •  This region is visible in the apical two-chamber view.
 

 

What percent thickening defines hypokinesis?

  •  <30% thickening during systole.
  •  Normal thickening = >30%
  •  Akinesis = no thickening
  •  Dyskinesis = bulging out
 

 

What’s the recommended method to quantify LV ejection fraction?

  •  Biplane method of disks (Simpson’s method).
  •  Most accurate for 2D echo.
  •  Avoids geometric assumptions.
  •  Preferred over FS or fractional area change, especially with regional wall issues.
 

 

Why is the biplane method better than linear methods?

  •  Linear methods assume LV is bullet-shaped.
  •   Biplane method:
    •  Measures actual endocardial borders
    •  Incorporates aneurysms into volume
  •   Can still be limited by:
    •  Foreshortened apex
    •  Endocardial dropout
    •  Missed out-of-plane wall motion issues
 

 

Which views are used in the biplane method of disks?

  •  Apical four-chamber
  •  Apical two-chamber
  •  Not used: apical long-axis (3-chamber view)
 

 

Do normal EF values differ between men and women?

  •   Yes, for normal EF:
    •  Men: 52%–72%
    •  Women: 54%–74%
  •   For moderate or severe dysfunction, cutoff is the same:
    •  Moderate: 30%–40%
    •  Severe: <30%
 

 

What measurements are used in Doppler cardiac output calculation?

  •  LVOT diameter → calculate cross-sectional area
  •  Velocity-time integral (VTI) at LVOT
  •  Heart rate
  •  These give stroke volume, then cardiac output
 

 

When is fractional shortening most accurate?

  •   In patients with:
    •  No wall motion abnormalities
    •  No conduction delays
    •  Normal LV shape
  •  Example: hyperdynamic states like sepsis
 

 

How do you identify end-diastole using biplane disks?

  •  Use the frame when the LV volume is largest.
  •  This is just after mitral valve closure.
  •  Often correlates with the R wave on ECG.
  •  Do not use the T wave or aortic valve opening.
 

 

How do you interpret EF in severe mitral regurgitation?

  •  EF may look normal (e.g. 56%) but be misleading.
  •  MR lowers afterload, making EF seem better than it is.
  •  Pre-op EF should be ≥60% for favorable post-op outcomes.
  •  <60% pre-op = higher risk of LV dysfunction after surgery
 

 

How do you measure EF in atrial fibrillation?

  •  EF is variable due to inconsistent filling.
  •  Average 5 beats for accuracy.
  •  Use a beat that doesn’t look like an outlier.
  •  In sinus rhythm, average at least 3 beats.
 

 

What global longitudinal strain indicates normal systolic function?

  •  <−20% is considered normal.
  •  Strain is negative because the ventricle shortens during systole.
  •  −30% = very good function
  •  0 or positive = abnormal
 

 

What non-ischemic conditions cause regional wall motion abnormalities?

  •  Left bundle branch block (LBBB)
  •  Ventricular pacing
  •  Subarachnoid hemorrhage or stroke
  •  All cause abnormal LV contraction patterns
 

 

How do you score wall motion abnormalities?

  •  Use the 17-segment model.
  •   Each segment gets a score:
    •  Normal/hyperkinetic = 1
    •  Hypokinetic = 2
    •  Akinetic = 3
    •  Dyskinetic = 4
  •  Wall motion score index = average of all segment scores
  •  Akinetic area (like in anterior MI) = score of 3