Thessaloniki, February 18, 2017
Cardiac Mechanics: The Physiological
Significance of the Left Ventricular
Ejection Fraction
Filippos K. Triposkiadis, MD, FESC, FACC
Professor of Cardiology
Director, Department of Cardiology
Larissa University Hospital
Larissa, Greece
Introduction
Conceptual Approaches to Cardiac Performance
De Keulenaer GW, Brutsaert DL. Circulation 2011;123:1996-2005
Left Ventricular Ejection Fraction (LVEF)
LVEF =
LVSV = (LVEDV - LVESV)
LVESV
LVEDV
LVEDV
Lang R, et al. J Am Soc Echocardiogr 2015;28:1-39
LVEDV
LV systolic function should be routinely assessed
using 2DE or 3DE by calculating EF from EDV and ESV.
LVEFs of <52% for men and <54% for women are suggestive
of abnormal LV systolic function.
Evolvement of the LVEF
•
Arvidsson H, 1961: SV and EDV by cardiac angiography in cardiac cycle; LVEF=SV/EDV; LVEF≈75% in 16 pts
with “sound hearts [and] only a vague suggestion of cardiac disease”. Acta Radiol 1961;56:321–339.
•
Folse R, Braunwald E, 1962: Radioisotope indicator dilution technique to assess the “fraction of left
ventricular volume ejected per beat”. Circulation 1962; 25: 674–685.
•
Gorlin R, et al. 1964: Thermodilution to measure ventricular volumes; LVEF ≈45% in pts with
normal hearts or mild MS. J Clin Invest 1964; 43:1203–1221.
•
Miller GA, et al. 1965: LVEF low in many patients with heart disease; LVEF a valid index of myocardial
contractility. Circulation 1965; 31:374–383.
•
Kennedy JW, et al. 1966: Angiographic, dye dilution and Fick methods to measure SV; LVEF ≈67%
in 21 pts with normal hearts. Circulation 1966; 34:272–278.
•
Dodge HT, et al. 1966: A low LVEF “evidence of LV disease” because, although generally normal in pts
with compensated VHD, markedly reduced in primary cardiomyopathies. Am J Cardiol 1966; 18:10–24.
•
Pombo JF, et al. 1971: Echocardiographic LVEF measurement that led to the widespread use of LVEF for
the evaluation of heart disease. Circulation 1971; 43:480–490.
•
Folland ED, et al. 1977: Radionuclide measurement of LVEF. J Nucl Med 1977; 18:1159–1166.
Peak dp/dt (mm. HG/second)
Myocardial Function and Left Ventricular
Volumes in Acquired Valvular Insufficiency
LV ejection fraction
Miller GA, et al. Circulation 1965;31:374-84
Contractility index
Ultrasound Assessment of LV Ejection
Fraction and LV Stroke Volume
Cameli M, et al. Heart Fail Rev (2016) 21:77–94
Pros and Cons of LVEF for
LV Systolic Function Assessment
Cameli M, et al. Heart Fail Rev 2016; 21:77–94
Definition/Classification of Heart Failure
Ponikowski P, et al. European Heart Journal 2016 ;37:2129–2200
LVEF as a Predictor of Cardiovascular
Outcomes at Values <45%
Cikes and Solomom
Eur Heart J 2016; 37:1642–50
Force Production and Transmission
in the Human Heart
Basic Structure of the Sarcomere
Hwang PM Sykes BD. Nat Rev Drug Discov 2015; 14:313-28
The Sarcomeric Cytoskeleton
Gautel and Djinović-Carugo.
Journal of Experimental Biology 2016; 219:135-145
Sarcomere-Mediated Mechanotransduction
and Mechanotransmission in Cardiac Muscle
Lyon RC. Circ Res 2015; 116:1462-1476
Cardiac Extracellular Matrix
Health
Rienks M, et al. Circ Res 2014;114:872-888
Myocardial Infarction
Generation of the Left Ventricular
Ejection Fraction
Left ventricular (LV)
ejection fraction≈60%
Myocardial fiber shortening≈15%
Myocardial fiber thickening≈8%
LV end-diastolic
volume
LV end-systolic
volume
?
Myocardial fiber
at end-diastole
Myocardial fiber at
end-systole
Left ventricular (LV)
ejection fraction≈60%
LV end-diastolic
volume
Myocardial fiber shortening≈15%
Myocardial fiber thickening≈8%
LV architecture
Intrasarcomeric
cytoskeleton
Extracellular
matrix
Extrasarcomeric
cytoskeleton
Non-contractile myocardial components
Myocardial fiber
at end-diastole
Myocardial fiber at
end-systole
LV end-systolic
volume
Helical Angle of Heart Layers
Partridge JB, et al. Heart 2014;100:1289–1298
Myocardial Fiber Connection
Ingels NB Jr. Technology and Health Care 1997; 5:45–52
Opposing Force Couples from Subepicardial
and Subendocardial Fibers
Ingels NB Jr. Technology and Health Care 1997; 5:45–52
Systolic Rotation Angle (degrees)
“Wringing” Motion of the Left
Ventricle During Systole
Ingels NB Jr. Technology and Health Care 1997; 5:45–52
The Cardiac Cycle Redefined
Sengupta, et al. J Am Coll Cardiol 2006; 47:163–72
Myocardial Fiber Orientation, Deformation
Planes and Typical Longitudinal Strain Rate
Cikes and Solomom Eur Heart J 2016; 37:1642–50
LV Twist/Torsion
Speckle-tracking Strain Echocardiography
PP Sengupta, et al. JACC Cardiovasc Imaging 2008;1:366-76
LV Shape and Fiber Orientation
in LV Hypertrophy
Phenotypes of LV Hypertrophy
Diastole
Systole
Addition of new sarcomeres
Normal
Eccentric
hypertrophy
(dilation)
Concentric
hypertrophy
Katz AM, Rolett EL. Eur Heart J 2016; 37:449-54
LV Twist and Strain in HFpEF vs. HFrEF
LV twist
(degrees)
Circumferential
Strain (%)
Longitudinal
Strain (%)
Radial
Strain (%)
Control
HFpEF
Wang, et al. Eur Heart J 2008;29:1283–9
HFrEF
Influence of Cardiac shape on LV Twist
45 DCM pts and 60 healthy volunteers studied. Speckle tracking echocardiography was used to determine basal and apical LV
peak systolic rotation (Rotmax) and instantaneous LV peak systolic twist (Twistmax). LV sphericity index was calculated by
dividing the LV maximal long-axis internal dimension by the maximal short-axis internal dimension at end-diastole.
van Dalen BM, et al. J Appl Physiol 2010; 108: 146–151
Relation between LVEF and Peak LV
Apical Rotation and Twist
van Dalen BM, et al. J Appl Physiol 2010; 108: 146–151
Left Ventricular Mechanics in DCM:
Assessment with Magnetic Resonance DTI
Dual heart-phase diffusion tensor imaging was performed in 9 DCM pts and 9 controls. Tagging data were acquired for the diffusion
tensor strain correction and cardiac motion analysis. Cardiac function was assessed by LVEF, torsion, and strain. Computational
modeling was used to study the impact of cardiac shape on fiber reorientation and how fiber orientations affect strain.
von Deuster C, et al. Circ Cardiovasc Imaging. 2016;9:e005018
Histograms of Diastolic and
Systolic Helix Angles
von Deuster C, et al. Circ Cardiovasc Imaging. 2016;9:e005018
Is Depressed Myocyte Contractility Centrally
Involved in HFrEF ?
Houser SR, Margulies KB. Circ Res 2003;92:350-358
Conclusions
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LVEF is dependent on the architecture of the left ventricle, which changes
gradually from a right-handed helix in the subendocardium to a left-handed
helix in the subepicardium.
LV strain, rotation, and torsion of the double helical left ventricle can be
assessed with current echocardiographic imaging modalities with great
potential clinical implications.
Several factors contribute to the decrease in LVEF in heart failure, one of the
most important being the abnormal myocardial fiber orientation, which in
turn is predominantly due to the disrupted non-contractile myocardial
components.
Delineating the physiological significance of the LVEF and the significance of
the factors leading to its decrease is essential for instituting the appropriate
treatment in patients with heart failure.