Assessment of Left Ventricle and Left Atrial Function by Speckle Tracking Echocardiography in Hypertensive Patients
Ziauddin University, Pakistan
Submission: November 27, 2019; Published: December 10, 2019
*Corresponding author: Imran Hameed, Anklesaria Nursing Home, Sir Aga Khan III Road, Garden, Karachi, Pakistan
How to cite this article:Imran Hameed. Assessment of Left Ventricle and Left Atrial Function by Speckle Tracking Echocardiography in Hypertensive Patients. J
Cardiol & Cardiovasc Ther. 2019; 15(3): 555912. DOI: 10.19080/JOCCT.2019.15.555912
Hypertension is a common clinical entity and is responsible for high cardiovascular morbidity and mortality. It affects especially the left sided chambers of the heart mainly i.e. the left ventricle and left atrium.
Conventional parameters can detect the dysfunction in these chambers when it is too late. Speckle tracking echocardiography a relatively new modality but by virtue of its ease of use, angle independency and robustness can detect dysfunction at a sub-clinical stage, when effective remedies can save the patient from the deleterious effects of hypertension. In this manuscript the basics and the present clinical status of speckle tracking echocardiography in hypertensive patients have been reviewed.
Hypertension affects a large section of nearly every society in the world. According to World Health Organization worldwide data, its overall prevalence in adult population was 26.4% (95% CI 26.0 - 26.8%) in 2000 and by 2025 this has been projected to 29.2% (CI 28.8 – 29.7%) . For this reason, it is one of the leading causes of CV mortality and morbidity especially heart failure . Besides its deleterious effects on various body parts, heart and blood vessels are its main targets especially left ventricle and left atrium. The main function of left ventricle is to pump blood to meet the metabolic requirements of the body, any deterioration in it causes profound effects. Left atrium as we know is not just a passive chamber and its functioning is needed by left ventricle for effective performance. For decades now echocardiography has
been the primary modality for assessment of cardiac chambers . This could be in the way of size (diameters and volumes) or function (LV-E.F., etc. LA-diastolic parameters).
Later research has shown that pathological changes in these parameters are appreciated much later by the conventional methods of echocardiography. Another parameter known as “strain” was found to detect changes in the function of these chambers much earlier. Strain is the ratio of change in length of an object to its resting length on application of a force:
Detection of strain involved many different modalities
like sonomicrometry and MRI tagging. The former, because
of its invasive nature, could not be used in routine medical
practice whereas tagged MRI, because of its cost and relative
unavailability, also cannot be used for this purpose as a routine
clinical tool. It has been found that during the acquisition of image
by 2-D echocardiography as ultrasound strikes the myocardium,
a part of it is reflected back, whereas much of it gets refracted
and scattered, producing “speckles.” Movement of these speckles
(each comprising of 20-25 pixels) during myocardial contraction
can be tracked frame to frame, Figure 1, thus the shortening (or
lengthening) of myocardial segment (and collectively of the whole
myocardium) can be assessed easily. This phenomenon is known
as “speckle tracking.”
Heart muscle, in left ventricle, is arranged in three layers with
muscle fibers in the sub-endocardial layer making an angle of 80
degrees (right-handed helix) with the horizontal and as they wrap
further towards the sub-epicardial layer get more horizontal,
making an angle of nearly 60 degrees (left-handed helix), Figure 2
well elaborated and illustrated by Sotoru Kishi .
Due to three layered orientation of muscle fibres in Left
ventricle contraction occurs in three directions as follows:
a) Longitudinal: shortening occurs along the length of left
ventricle mainly due to sub-endocardial fibers.
b) Circumferential: shortening occurs along the
circumference of left ventricle mainly due to mid myocardial
c) Radial; thickening occurs towards the center of left
ventricle mainly due to mid and sub-epicaradial fibres.
Speckles generated by these three layers can be tracked in
the three directions of their movement during contraction  as
shown in Figure 3, which are referred to as strain of that particular
type , Figure 4. By assessment of circumferential strain, we can
calculate the basal and apical rotation of left ventricle as well. The
difference between these two is “twist” and dividing it by the LV
length, gives “torsion.”
Left atrium serves three functions viz. reservoir, conduit and
contractile, all of which can be assessed by tracking speckles of
LA wall  as shown in Figure 5. Changes in these parameters are
noted much earlier than any change in size or diastolic parameters
can be demonstrated.
For LV assessment, data is acquired by obtaining three apical
views (4C, 2C and 3C) Figure 6 and three parasternal short-axis
views (at base, mid and apex).
Image depth and frame rate (40-100) should be so set as to
get an optimal view and Region of Interest (ROI) is over layed the
2-D image, encompassing the myocardium totally. Analysis can
be done live or offline (by special software) and represented by
graphs (Figure 7) and a bull’s-eye view (Figure 8) showing the
strain values of individual segments with outer circle for basal
segments, mid for middle segments and inner circle for apical
For LA strain acquisition, apical 4 and 2-chamber views are
sufficient and a varied number of segments [6-12] are assessed
although now total peak longitudinal and contractile strain values
are recommended  as shown in Figure 9.
Hypertension leads to myocardial fibrosis (essentially
deposition of type I Collagen), which causes decreased diastolic
relaxation as tissues get stiff and later on systolic dysfunction
ensues as myocytes are unable to translate contraction into force
(9 and 10).
Normal myocardium comprises of myocytes (1/3 of cell),
endothelial, vascular smooth muscle cells and fibroblasts which
make up rest of the cells . Extracellular matrix comprises
of proteins and polysaccharides. Hypertension affects both the
components, cellular and non-cellular causing hypertrophy of
former and deposition of fibrous tissue in later .
This has been aptly demonstrated by Roman Querejeta
et al.  in their study of 77 patients (34 hypertensives with
heart failure, 31 with hypertension only and 12 controls) by
correlating HTN, clinical HF, biochemical molecules of fibrosis
and histopathology of mid interventricular septal muscle by
endomyocardial biopsy. Cardiovascular fibrosis was significantly
higher (p< 0.001) in HTN patients than control subjects more so
(significantly high) in HTN with HF (7.95 ± 0.55% vs 5.38 ±0.31%;
Extent of collagen deposition was significantly high in HTN
group especially with HF. Further the synthesis of PIP (Propeptide
of ProCollagen Type I) was significantly high in HTN group than
control. They found a direct correlation level of PIP level in
coronary sinus and peripheral vein with cardio-vascular fibrosis
(coronary r = 0.759; p<0.001 and peripheral r = 0.867; p < 0.001).
All these findings showed significant inverse correlation of EF
with cardio-vascular fibrosis (r = -0.393; p < 0.001), coronary PIP
(r = 0.387; p < 0.05) and peripheral PIP levels (r = 0.256; p < 0.05).
Mizuno et al.  found excellent correlation between the
amount of fibrosis and integrated backscatter
It has been shown by Louis Antonio Moreno-Ruiz et al. .
that in hypertension, level of oxidized proteins and lipid oxidation
are enhanced and activity of antioxidants like superoxide
dismutase, glutathione peroxidase and catalase decrease, causing
increased oxidation stress which alters the cellular signaling
pathway and modulation of growth, apoptosis, hypertrophy,
inflammation and remodeling of cardiac muscle. This oxidation
stress leads to accumulation of extracellular matrix, interstitial
and perivascular fibrosis, and myocyte hypertrophy. All these
changes lead to sub-clinical LV dysfunction as assessed by strain
measurement in their study of 50 patients (25 HTN vs 25 controls).
Both groups showed normal 2-D echo LVEF. They found a positive
correlation between levels of oxidized proteins and GLS (r = 0.386;
p = 0.006) and a negative correlation of extracellular superoxide
dismutase with GLS (r = 0.404; p = 0.004) as the oxidative stress
accentuates or gets prolonged, first diastolic dysfunction and later
on deterioration in EF is noted.
Numerous studies are now available in literature, showing
that in spite of preserved EF as assessed by 2-D echo, reduced
strain values are seen when speckle tracking echocardiography
is done. Shantanu P Sengupta et al. . in their study of 59
subjects (34 HTN vs 25 control) assessed layered strain and found
sub-endocardial and sub-epicardial regions showed reduced
longitudinal strain, whereas circumferential strain was reduced
in sub-epicardial region only, radial strain was no different in the
Xio-Xia Luo et al.  while comparing 40 youths (age range
18 ± 3 years) with masked hypertension and 40 age-matched
normotensive controls found that longitudinal strain (subendocardial
and mid-myocardial) along with circumferential
strain was significantly reduced in hypertensive group (p < 0.05);
no difference was noted with regard to radial strain and apical
rotation. 2-D echo EF was normal in the two groups.
Reduction in GLS has been correlated with the pattern of LV
geometry in hypertensive patients. Susana Goncalves et al. 
in their study of 20 normotensive and 229 hypertensive patients
found no difference in GLS between the two groups. However,
hypertensive group showed 15.3% of the subjects to have reduced
GLS and the pattern of reduction correlated with LV geometrical
pattern. Concentric remodeled type showed the least drop in strain
value and concentric hypertrophy showed the most. In another
study, Ting-Yan Xu et al.  showed the pattern of strain in the
four geometrical types of LV in hypertensive patients. Longitudinal
strain was reduced significantly in all types of geometrical patters
in all the layers except for normal geometrical pattern (all three
layers), mid and epicardial layers in concentrically remodeled
pattern in which the drop was not significant. Circumferential
strain was increased for sub-endocardial and mid wall in
normal geometrical patters and in subendocardial strain in
concentrically remodeled pattern. For other layers in these two
geometrical patterns it was non-significantly increased. However,
it was significantly reduced for all the layers in concentrically
hypertrophic and eccentrically hypertrophic types of geometrical
patterns. Radial strain did not show any difference for any type of
geometrical pattern and for any layer.
Reduction in GLS, as a marker of sub-clinical LV dysfunction
in hypertensive patients, has been detected not only during rest
but also with exercise. Kai O Hansel et al. , in their study of
92 patients (46 HTN vs 46 control) found that both at rest and
after exercise, the strain values were lower significantly in HTN
subjects. Brain natriuretic peptide (BNP), along with its fragment
N-terminal B type Natriuretic Peptide (NT-Pro BNP) is released
by myocytes when put on a stretch. These are usually elevated
in patients with LVH, thus relating to cardiac remodeling and
diastolic dysfunction. Waleed Abdou Ibrahim Hamed et al.  in
their study of 106 patients (80 HTN vs 26 control) showing normal
EF by 2-D echo, found a negative correlation between BNP level
and global peak systolic strain, global systolic strain rate, early
and late diastolic strain rate in HTN patients with significantly
increased BNP levels as compared to control subjects.
Sadiya S Khan et al.  in HYPERGEN study (2058
participants) found that LS, e’ velocity and early diastolic strain
rate were heritable traits whereas no such association was noted
with GCS and GRS.
Left atrium not only acts as a reservoir and conduit of blood
transfer to LV but also contributes (25-30%) of LV cardiac
output by virtue of its contractile function. Speckle tracking
echocardiography can detect deterioration in various LA
parameters in HTN patients much before any change in its size
or parameters of diastolic LV function could be noted. This has
been shown by Bassam Hennawy et al.  in their study of 100
subjects (50 HTN vs 50 control) that global peak atrial longitudinal
strain was significantly reduced in hypertensive patients (41.36 ±
2.86 vs 24.00 ± 6.92 p = 0.00).
Hypertension is a leading cause of atrial fibrillation and this
especially happens when LA gets enlarged and shows fibrosis in
its wall. Atrial fibrillation by itself has got many adverse sequelae.
Parameters were searched to detect its potential of occurrence
much before any change in LA size or function happens. Ioana
Petra et al. , in their study of 108 patients (67 with HTN only
vs 41 with HTN and one episode of recent AF) found that although
both groups showed normal LVEF but PALS and PACS showed
good discriminatory capacity as predictors of AF (AUC = 0.88 for
PALS and AUC = 0.86 for PACS).
Speckle tracking echocardiography as an emerging tool for
the assessment of left ventricular and left atrial function has
clearly demonstrated its utility in the detection of sub-clinical
dysfunction of these chambers, much before the conventional
methods can detect it. Because of its ease of availability, angle
independency, robustness and provision of off-line assessment, this modality need be incorporated in every echocardiographic
study especially when dealing with hypertensive patients in view
of the nearly epidemic prevalence of this clinical entity.