LV function echocardiography
LV Function and Haemodynamic Assessment Echocardiography
SYSTOLIC FUNCTION
Global Function
- stroke volume: end-diastolic volume – end-systolic volume
- cardiac output:
Q = SV X HR
= (Aortic Area x V x Tej) x HR
Q = cardiac output
Aortic area = cross sectional area
V = velocity for each beat
Tej = time period during ejection
HR = heart rate
- ejection fraction: take two orthogonal views (apical four chamber and apical two chamber) ⇒ trace around endocardial border at the end of diastole and systole
EF = (EDV-ESV/EDV) x 100
(normal = 50-85%)
- fractional shortening: percentage change in LV internal dimensions between systole and diastole (normal 30-45%)
- preload: end-diastolic volume (if low think -> hypovolaemia, low SVR, severe AR or MR, VSD)
- afterload: end-systolic wall stress (rarely used in clinical practice)
- LV wall thickness: > 1.5cm = LVH, < 0.6cm = LV thinning
Regional Function
- 16 segments
- contractility: grades
1 = normal or hyperkinetic
2 = hypokinetic
3 = akinetic
4 = dyskinetic (paradoxical systolic motion)
5 = aneurysmal
DIASTOLIC FUNCTION
- relaxation requires energy (ATP)
- phases of relaxation = isovolumetric relaxation, early filling, diastasis (when LA passively fills LV and then stops), atrial contraction
- diastolic dysfunction = disorder of LV filling where LV is unable to fill to a normal LVEDV without an increase in end-diastolic pressure.
- m-mode ‘slow relaxation’ in motion of the anterior mitral valve leaflet.
- normal = E > A
- abnormal = A > E
- pseudonormal = E > A (LA dilated to compensated for lack of LV relaxation)
- restrictive = E >>> A
References and Links
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.
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