The EACVI Textbook of Echocardiography (2 edn)
Patrizio Lancellotti (ed.) et al.
https://doi.org/10.1093/med/9780198726012.001.0001
Published online: 01 December 2016 Published in print: 01 November 2016 Online ISBN:
9780191792991 Print ISBN: 9780198726012
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CHAPTER
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25 Heart failure: left ventricular systolic dysfunction
Erwan Donal, Elena Galli
https://doi.org/10.1093/med/9780198726012.003.0025 Pages 193–196
Published: November 2016
Abstract
Heart failure (HF) is a growing problem worldwide and poses an especially large public health burden.
It represents a new epidemic of cardiovascular disease, a ecting nearly 5.8 million people in the United
States, and over 23 million worldwide. Nevertheless, in Europe, fears of an impending HF ‘epidemic’
could not be con rmed in this analysis of trends in prevalence for the period 1990-2007 in patients
hospitalized with HF in Sweden. An overall slight decrease in age-adjusted prevalence was observed
from 2002. The prevalence in patients under 65 years increased markedly. In absolute numbers, there
was a substantial increase among the very old, consistent with demographic changes. The complexity
of left ventricular function(s) assessment in HF patients is related to the complexity of heart anatomy,
but also to the complexity of electromechanical interaction, and to the load dependency of all the
parameters that could be applied in clinical practice.
Keywords: heart failure, le ventricular systolic dysfunction, le ventricular ejection fraction, deformation
imaging, Simpson biplane method
Collection: Oxford Medicine Online
Contents
Summary 193
Echocardiographic approach for left ventricular systolic dysfunction 193
Left ventricular ejection fraction 193
Deformation imaging 194
Other approaches 196
Conclusion 196
Summary
Heart failure (HF) is a growing problem worldwide. HF poses an especially large public health burden. It
represents a new epidemic of cardiovascular disease, a ecting nearly 5.8 million people in the United States,
and over 23 million worldwide. Nevertheless, in Europe, fears of an impending HF ‘epidemic’ could not be
con rmed in this analysis of trends in prevalence for the period 1990–2007 in patients hospitalized with HF
in Sweden. An overall slight decrease in age-adjusted prevalence was observed from 2002. The prevalence in
patients under 65 years increased markedly. In absolute numbers, there was a substantial increase among
the very old, consistent with demographic changes.
The complexity of left ventricular (LV) function(s) assessment in HF patients is related to the complexity of
Downloaded from https://academic.oup.com/esc/book/29606/chapter/249429038 by guest on 11 December 2024
heart anatomy, but also to the complexity of electromechanical interaction, and to the load dependency of
all the parameters that could be apply in clinical practice. (See Chapter 19 in this textbook regarding
cardiac mechanics and left ventricular performance.)
Echocardiographic approach for le ventricular systolic dysfunction
Le ventricular ejection fraction
The rst parameter that has to be provided in echocardiographic reports of patients evaluated for HF is the
LV ejection fraction (EF). This has been for many years the key parameter, supposed to represent LV systolic
function. Many therapeutic decisions will be taken based the value of the LVEF. All current guidelines ask for
the method of discs, that is, the biplane Simpson method presented in Fig. 25.1. This method takes
advantage of the improvement in image contrast and in the capability to clearly see the endocardial borders
in end-systole and end-diastole. The method remains di cult, however, and su ers from rather poor
reproducibility and repeatability. Automatic or semi-automatic algorithms are now available and might
help the clinician in the daily routine practice.
Fig. 25.1 Automatic measurement of le ventricular volumes in systole and diastole for an automatic calculation of the
ejection fraction (Simpson method).
The three-dimensional (3D) approach is now available on many echo platforms. If the image quality is
su cient, this should be used. Currently, this 3D approach has to be considered in addition to the biplane
two-dimensional (2D) Simpson method. Perhaps in the near future, it will replace the 2D measurement. The
3D semi- or totally automatic measurement of LVEF is based on a real measurement not a calculation of the
LV volumes. It is rapid and reliable in experiments. The value of LV cavity opaci cation for improving the
measurement of LV volumes and EF in 2D ( Fig. 25.2) has been demonstrated, but is still questionable in
3D.
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Fig. 25.2 Use of an ultrasonic contrast agent to improve the echocardiographic detection of le ventricular endocardial
borders. It will help to best quantify the le ventricular geometry and systolic function.
Deformation imaging
The assessment of LVEF is just the di erence between LV end-diastolic and end-systolic volumes
associated with the heart rate. This is not a measurement of LV contractility. It is geometry and load
dependent and has to be used but, currently, it is necessary to consider the echocardiographic assessment of
other parameters of LV systolic function.
The background for this echocardiographic assessment of cardiac systolic function in HF is that, during a
cardiac cycle, the LV wall shortens, thickens, and twists along the long axis. Shortening and thickening can
be quanti ed by measuring regional strain. Strain or myocardial deformation from developing forces is
expressed as either the fractional or the percentage change from the original dimension. Positive radial
strains represent wall thickening (radial deformation), whereas negative strains represent segment
shortening (e.g. circumferential shortening, longitudinal shortening, and bre shortening) ( Fig. 25.3;
di erent component of LV deformations in systole).
Fig. 25.3 Assessment of regional and global le ventricular longitudinal strain.
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Three perpendicular axes orienting the global geometry of the LV de ne the local cardiac coordinate system:
radial, circumferential, and longitudinal.
Echocardiographic techniques like tissue Doppler imaging have excellent temporal resolution (± 4 ms) and
provide the instantaneous velocity of myocardial motion. The velocity data can be post-processed for
calculating parameters such as displacement, strain rate, and strain. Numerical integration of velocity over
time results in displacement curves. Strain rate, which is the rate of change of deformation, is derived as a
spatial derivative of velocity, whereas temporal integration of strain rate is used for calculating regional
strain.
The base and apex of the LV rotate in opposite directions. Twist de nes the base-to-apex gradient in the
rotation angle along the longitudinal axis of the LV and is expressed in degrees per centimetre. Torsion and
twist are equivalent terms. Torsion also can be expressed as the axial gradient in the rotation angle
multiplied by the average of the outer radii in apical and basal cross-sectional planes, thereby representing
the shear deformation angle on the epicardial surface (unit degrees or radians). This normalization can be
used as a method for comparing torsion for di erent sizes of LV. When the apex-to-base di erence in LV
rotation is not normalized, the absolute di erence (also in degrees or radians) is stated as the net LV twist
angle. These torsion parameters remain in the domain of research and are still not robust enough to be
applied in routine clinical practice.
Using speckle tracking echocardiography, a technique that analyses motion by tracking natural acoustic
re ections and interference patterns within an ultrasonic window, assessment of LV deformation is starting
to be largely implemented in clinical practice and in the routine evaluation of patients with HF. The image-
processing algorithm tracks user-de ned regions of interest which are comprised of blocks of
approximately 20–40 pixels containing stable patterns that are described as ‘speckles’, ‘markers’,
‘patterns’, ‘features’, or ‘ ngerprints’. Speckles are tracked consecutively frame to frame using a sum-of-
absolute di erences algorithm to resolve angle-independent 2D and 3D sequences of tissue motion and
deformation. Data regarding the accuracy, validity, and clinical application of speckle tracking imaging are
rapidly accumulating. The robustness and the clinical applicability are nowadays only validated for the
assessment of global longitudinal strain. Even when considering regional longitudinal strains, there are
inaccuracies according to the software used. Longitudinal LV mechanics, which are predominantly governed
by the subendocardial region, are the most vulnerable component of LV mechanics and therefore most
sensitive to the presence of myocardial disease. The mid-myocardial and epicardial function may remain
relatively una ected initially, and therefore circumferential strain and twist may remain normal or show
exaggerated compensation for preserving LV systolic performance. An increase in cardiac muscle sti ness,
however, may cause progressive delay in LV untwisting. Loss of early diastolic longitudinal relaxation and
delayed untwisting attenuates LV diastolic performance, producing elevation in LV lling pressures and a
phase of predominant diastolic dysfunction, although the LVEF may remain normal. On the other hand, an
acute transmural insult or progression of disease results in concomitant mid-myocardial and subepicardial
dysfunction, leading to a reduction in LV circumferential and twist mechanics and a reduction in LVEF.
Assessment of myocardial mechanics, therefore, can be tailored per the clinical goals. The detection of
altered longitudinal mechanics alone may su ce if the overall goal of analysis is to detect the presence of
early myocardial disease. Further characterization of radial strains, circumferential strains, and torsional
mechanics provides assessment of the transmural disease burden and provides pathophysiological insights
into the mechanism of LV dysfunction. For example, pericardial diseases, such as constrictive pericarditis,
cause subepicardial tethering and predominantly a ect LV circumferential and torsional mechanics. The
presence of attenuated longitudinal mechanics in constrictive pericarditis may signify the presence of
transmural dysfunction. As another example, a pathophysiological process such as radiation that a ects
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both the pericardium and the subendocardial region may produce attenuation of both longitudinal and
circumferential LV function.
From a clinical standpoint and trying to translate the quanti cation of myocardial deformation in clinical
practice, the study of longitudinal strain has been proposed. This is a simple and robust tool that can well
characterize the LV systolic function (which is slightly di erent from contractility).
One can keep in mind that in systolic HF, a global longitudinal strain less than −7% is an independent
parameter of severity of the cardiomyopathy. In HF with preserved EF, the prognostic cut-o the most
frequently reported is −16%.
In more complex cardiomyopathies like the ones induced by anthracyclines, it seems that as soon as the
global longitudinal is less than −19%, physicians have to monitor patients and studies are ongoing to
investigate if dedicated treatments such as angiotensin-converting enzyme inhibitors and beta blockers
should be introduced.
Using strain data, especially longitudinal strain data, is something one has to think about for routine
practice, but the key marker of LV systolic function that will be used to decide on the use of an implantable
cardioverter de brillator or biventricular pacemaker is the LVEF. This should be measured according to
recommendations using the apical four- and two-chamber views using the Simpson method. The M-mode
should not be used, especially in hearts undergoing spherical remodelling.
Other approaches
Pulsed wave tissue Doppler is the most relevant approach. It is a way to assess LV longitudinal systolic
function as well as mitral annular plan systolic excursion (MAPSE) ( Fig. 25.4).
Fig. 25.4 Assessment of the longitudinal component of the le ventricular systolic function. MAPSE: mitral annular plan
systolic excursion measured by M-mode. S′: pulse tissue Doppler recording systolic and diastolic velocities where s′ corresponds
to the systolic peak velocity of the displacement of the mitral annulus. Longitudinal global strain: assessment of the longitudinal
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deformation of the whole le ventricle using the speckle tracking technique.
In addition to these measurement (LVEF required, global longitudinal strain strongly encouraged or at least
s′), one has to measure the LV stroke volume (Doppler and volumetric approaches) for estimating the
cardiac output and nally the e cacy of this LV contractility to eject enough blood in the arterial tree (
Fig. 25.5).
Fig. 25.5 Representation of the technique to measure cardiac output and stroke volume. The pulsed wave Doppler velocity
time integral (VTI) of the flow recorded in the le ventricular outflow tract (LVOT), 1 cm below the aortic valve (before the
turbulent flow due to the aortic valve). Cardiac output = heart rate × LVOT VTI (cm) × LVOT area (calculated with the diameter
2 2
measured: 3.14 × LVOT diameter /4). The normal stroke volume > 35 mL/m and cardiac output > 4 L/min.
Conclusion
It is important to know how to measure the LVEF using the Simpson biplane method. It is also important to
learn how to use 3D approaches and to consider rather systematically the speckle tracking approach, at least
to measure LV longitudinal global strain.
© European Society of Cardiology
