|Year : 2019 | Volume
| Issue : 3 | Page : 855-860
Subendocardial systolic dysfunction in hypertensive patients with strain ST-T changes on ECG by speckle tracking
Mahmoud A Soliman1, Morad B Mena1, Gerges R Thabet2
1 Department of Cardiovascular Diseases, Faculty of Medicine, Menoufia University Hospitals, Shebin El Kom, Egypt
2 Resident of Cardiology at Health Insurance Hospital, Sohag, Egypt
|Date of Submission||22-Dec-2017|
|Date of Acceptance||29-Jan-2018|
|Date of Web Publication||17-Oct-2019|
Gerges R Thabet
10 El-kashef St, Sohag Governorate
Source of Support: None, Conflict of Interest: None
The aim of this study was to evaluate longitudinal strain by speckle tracking in hypertensive patients with strain ST-T on ECG.
Hypertension causes ST-T changes on ECG which may predict subclinical systolic dysfunction detected by two-dimensional speckle tracking.
Patients and methods
Longitudinal strain analysis was done in 82 hypertensive patients, who were divided into three groups: the first group included 30 hypertensive patients with echocardiographic evidence of left ventricular hypertrophy (LVH) and strain ST-T changes on ECG (group 1), the second included 31 hypertensive patients with echocardiographic evidence of LVH but without changes on ECG (group 2), and the third control group included 21 hypertensive patients without echocardiographic evidence of LVH (group 3).
A high significant difference was detected in relation to hypertension duration, which divided into two categories (>10 and ≤10 years) (P < 0.001). A highly significant increase was present regarding echocardiography data on left ventricular (LV) mass (P < 0.001), LV mass index (P < 0.001), relative wall thickness (P < 0.001) and interventricular septum (P < 0.001), posterior wall (P < 0.001), left atrium (P < 0.001), and aorta diameters (P < 0.001) between group 1 compared with group 2 and group 3. Moreover, significant decrease was found on Doppler data regarding E/A ratio between group 1 compared with group 2 and group 3. There was a highly significant reduction between group 1 compared with group 2 and group 3 regarding mean value of global and regional LV longitudinal systolic strain (P < 0.001).
Subtle LV systolic dysfunction evident by speckle tracking was present in hypertensive patient with strain ST-T changes on ECG independent of left ventricular ejection fraction percentage.
Keywords: ECG, hypertension, left ventricular hypertrophy, speckle tracking
|How to cite this article:|
Soliman MA, Mena MB, Thabet GR. Subendocardial systolic dysfunction in hypertensive patients with strain ST-T changes on ECG by speckle tracking. Menoufia Med J 2019;32:855-60
|How to cite this URL:|
Soliman MA, Mena MB, Thabet GR. Subendocardial systolic dysfunction in hypertensive patients with strain ST-T changes on ECG by speckle tracking. Menoufia Med J [serial online] 2019 [cited 2019 Nov 19];32:855-60. Available from: http://www.mmj.eg.net/text.asp?2019/32/3/855/268857
| Introduction|| |
Hypertension is a well-recognized risk factor for cardiovascular diseases. It causes left ventricular (LV) systolic pressure overload owing to increase in peripheral vascular resistance. As a result, various geometric changes are present in this disease , which progress to diastolic dysfunction with or without symptoms of heart failure (HF) and/or HF with systolic dysfunction. According to Framingham study, left ventricular hypertrophy (LVH) is an established risk factor in myocardial infarction and cardiovascular mortality .
The classic LV strain pattern of ST-segment depression and T-wave inversion on the left precordial leads of the standard resting ECG is a well-known marker of presence of anatomic LVH ,,,. Furthermore, the occurrence of this ECG abnormality of ventricular repolarization has been associated with worse prognosis in both hypertensive patients  and general populations .
However, this relationship between ST-T changes on surface ECG and subendocardial dysfunction in hypertensive patients has not been clarified.
Two-dimensional (2D) speckle tracking echocardiography analysis is a more sensitive technique and allows the identification of early markers of myocardial dysfunction before the impairment of conventional echocardiographic parameters .
In contrast to tissue Doppler imaging (TDI), STE is an angle-independent technique that may allow an accurate assessment of segmental myocardial deformation by gray-scale-based imaging analysis frame by frame. Moreover, the lack of angle dependency is of a great advantage because myocardial strain could be tracked in 2D echocardiography imaging, along the direction of the wall and not along the ultrasound beam .
The aim of study was to detect the role of strain ST-T changes on ECG on LV systolic function in hypertensive patients by speckle tracking.
| Patients and Methods|| |
This is a cross-sectional study that enrolled 82 individuals after obtaining their written informed consent and approval of Ethics Committee of Menoufia University.
They were divided into three groups: the first group included 30 hypertensive patients with echocardiographic evidence of LVH and strain ST-T changes on ECG (group 1), the second group included 31 hypertensive patients with echocardiographic evidence of LVH but without changes on ECG (group 2), and the third control group included 21 hypertensive patients without echocardiographic evidence of LVH (group 3).
Patients with systemic hypertension were defined according to European Society of Hypertension/European Society of Cardiology guidelines for the management of hypertension systolic blood pressure greater than or equal to 140 mmHg and/or diastolic blood pressure greater than or equal to 90 mmHg on two or more hospital visit at 1-week interval.
Exclusion criteria included patients with LV systolic dysfunction (EF < 50%), hypertrophic cardiomyopathy, known coronary artery diseases, significant valvular diseases, and atrial fibrillation or other rhythm disturbances.
All patients were subjected to the following:
- Full medical history, medical examination, routine laboratory investigation (complete blood count, serum creatinine, serum glutamate pyruvate transaminase, and serum glutamic oxaloacetic transaminase)
- Standard 12-lead ECG: ECG strain was defined as a down sloping convex ST-segment depression combined with an inverted asymmetrical T-wave with polarity opposite to the main QRS deflection in leads V5 and/or V6. No specific magnitude of ST-segment depression was required for the diagnosis of ECG strain [Figure 1]
- Transthoracic echocardiography: echocardiographic examination with Vivid 9 GE (GE Healthcare, Australia, 911Silverwater NSW 1811) will be performed with patients in the left lateral decubitus position at end-expiration according to the recommendations of the American Society of Echocardiography and connected to single lead ECG . All standard measurements were obtained in the parasternal long-axis and short-axis views and apical four-chamber, two-chamber, and apical long-axis views. End-diastolic ventricular septum thickness (interventricular septum diameter), end-diastolic posterior wall thickness (posterior wall diameter), left ventricular end-diastolic diameter, and left ventricular end-systolic diameter were measured. Fractional shortening and ejection fraction were calculated
- 2-D speckle tracking echocardiography: the endocardial border was manually traced in the end-systolic frame was performed using custom analysis software (Echo Pac, PC, version 1.8.1.X; GE Healthcare, Australia, 911Silverwater NSW 1811) commercially available 2D-strain software a region of interest was then drawn to include the entire myocardium. The software algorithm automatically tracked the speckle patterns in the myocardium on a frame-by-frame basis using the sum of absolute differences algorithm. Finally, the software automatically generated LV strain curves during one cardiac cycle, from which end-systolic strain was measured. End-systolic strain at each level (basal, mid, and apical) and global strain obtained from averaging the strain values of the three levels were calculated. End systole was defined at the time of aortic valve closure. End diastole was defined as the point of the R-wave on the ECG
- Results were statistically analyzed by SPSS version 20 (SPSS Inc., Chicago, Illinois, USA). One-way analysis of variance (F-test) is a single test used to collectively indicate the presence of any significant difference between several groups for a normally distributed quantitative variable. Kruskal–Wallis test is nonparametric version of analysis of variance. Post-hoc test was used to show any significant difference between the individual groups. χ2 was used to compare between groups regarding qualitative variables. P value was set to be significant if less than or equal to 0.05.
|Figure 1: ECG for patient with left ventricular hypertrophy and strain pattern.|
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| Results|| |
A high significant difference was detected between study groups in relation to hypertension duration, which was divided into two categories (>10 and ≤10 years) based on the median duration of hypertension in patients (P < 0.001). Patients in group 1 had 22 patients with hypertension greater than 10 years and eight of them had hypertension for less than or equal to 10 years; in group 2, 12 patients had hypertension for greater than 10 years and 19 of them had hypertension for less than or equal to 10 years; and in group 3, only three of them had hypertension for less than or equal to 10 years and 18 of them had hypertension for less than or equal to 10 years [Table 1].
Regarding conventional echocardiography, a highly significant increase in relative wall thickness (RWT) was detected in group 1 patients (0.61 ± 0.10) when compared with those in group 2 (0.52 ± 0.08) and control group 3 (0.37 ± 0.03). Additionally, group 1 patients had greater interventricular septum (1.64 ± 0.21 mm), posterior wall (1.43 ± 0.12 mm), and left atrium (4.16 ± 0.29 mm) diameters compared with group 2 patients, who had interventricular septum diameter of 1.20 ± 0.09 mm, posterior wall diameter of 1.17 ± 0.08 mm, and left atrium diameter of 3.64 ± 0.42 mm, and group 3 patients, who had interventricular septum diameter of 0.90 ± 0.08 mm, posterior wall diameter of 0.87 ± 0.07 mm, and left atrium diameter of 3.39 ± 0.34 mm. Regarding LV mass and LV mass index, group 1 patients had larger LVM (316.17 ± 62.85 g) and LVMI (157.70 ± 28.98 g/m 2) compared with group 2 patients (LVM = 199.90 ± 46.17 g and LVMI = 102.26 ± 21.86 g/m 2) and group 3 patients (LVM = 138.19 ± 32.15 g and LVMI = 72.28 ± 15.15 g/m 2) [Table 2].
Regarding Doppler echocardiographic data, there was significant difference regarding E/A ratio between study groups (P = 0.019), whereas other parameters of mitral inflow velocity assessed by pulsed-wave Doppler [early mitral inflow velocity (E), late atrial inflow velocity (A), and deceleration time (DT)] showed no significant difference between hypertensive patient groups [Table 3].
Although left ventricular ejection fraction (LVEF) was not different between groups, global and regional longitudinal systolic strains were significantly lower in group 1 patients compared with group 2 and control group 3 patients (P < 0.001). Moreover, there is a significant difference in average global and regional longitudinal systolic strain values between group 2 and group 3 patients (P < 0.001) [Table 4].
| Discussion|| |
A total of 82 hypertensive individuals were enrolled in this study and divided into three groups. All study populations were known to be hypertensive, with some of them having associated risk factor such as diabetes (50% in group 1, 51.6% in group 2, and 28.6% in group 3) and smoking (36.7% in group 1, 29% in group 2, and 9.5% in group 3) which appear to be nonsignificant in the results of our study. In this study, all patients underwent global and regional (apical 2, apical 3, and apical 4) longitudinal strain imaging using 2D-speckle tracking.
Early manifestations of cardiac abnormalities are usually observed in the subendocardial layers owing to specific characteristics of coronary perfusion and myocardial demand. Previous TDI studies and recent 2D-speckle tracking studies have demonstrated a reduction in longitudinal strain and strain rate in patients with hypertension, diabetes, and HF and normal LVEF ,,. Although there was no significant relation between strain ST-T changes on ECG and LVEF as explored with conventional echocardiography in our study, we demonstrated that global and regional (anterior and inferior walls in apical 2 view, anteroseptal and posterior walls in apical 3 view, and septal and lateral walls in apical 4 view) longitudinal strains in group 1 patients with strain ST-T change were significantly reduced compared with group 2 patients without strain ST-T changes and control group 3 without LVH, a finding that indirectly supports the notion that strain ST-T changes reflect subendocardial dysfunction. In addition, multivariate regression analysis showed that not LV mass index but the presence of strain ST-T change is an independent predictor of global longitudinal strain (GLS). This goes with Nishikage et al.  who addressed that longitudinal strain was significantly reduced in hypertensive patients with strain ST-T changes compared with those without these changes or controls. Moreover, Salles et al.  documented importance of strain pattern as a predictor of systolic dysfunction, LVH, and adverse cardiovascular prognosis; in a study done on 440 resistant hypertensive patients, ECG strain pattern was present in 101 (23%) patients. Patients with strain had more target-organ damage than those without strain. Moreover, the study by Tulika et al.  conducted on 72 hypertensive patients with preserved EF (mean age: 46.1 ± 11.1 years) postulated that the early features of LV systolic dysfunction in hypertension with apparently normal-appearing LV systolic function was in the axial axis, whereas the systolic shortening in circumferential and radial axis were preserved.
Our article is unique in detecting the effect of duration of hypertension on the LV systolic function by speckle tracking, but this observation needs to be investigated by more and large studies.
Regarding the effect of LV mass index on GLS in our study, it was higher in hypertensive patients with subclinical LV systolic dysfunction (reduced GLS) than hypertensive patients with normal GLS, and this goes with the study of Tulika et al.  which shows that LV mass index and diastolic blood pressure were found to be independent predictors of reduced global strain in longitudinal axis.
]In our study, 24.4% of hypertensive patients had normal LV geometry and 75.6% had abnormal LV geometry in the form of 19.5% having concentric remodeling, 43.9% having concentric hypertrophy, and 12% patients having eccentric hypertrophy. This is similar to the results of Zabalgoitia et al. , who examined the relation of LV mass, RWT, and systolic and diastolic interaction in 508 hypertensive patients between 50 and 80 years of age and showed that the most common LV geometric remodeling was increased RWT in the form of concentric hypertrophy or concentric remodeling. Moreover, the study done by Gonçalves et al.  showed that the likelihood of LV systolic dysfunction was three times greater in those with concentric LV hypertrophy than other LV geometric patterns.
LVH has been suggested to mediate the relation between hypertension and left atrial enlargement. In our study, LA diameter was higher in hypertensive patients with LVH and strain pattern in group 1 than in hypertensive patients with LVH and without strain pattern in group 2 and control group 3. This goes with the study by Cuspidi et al. , which clarified that LA enlargement is a common echocardiographic finding in selected essential hypertensive patients with different LV geometric patterns, being greater in patients with concentric or eccentric LVH than in those with LV concentric remodeling or normal geometry.
Aortic root dilatation (ARD) and arterial hypertension represent two important risk factors for aortic dissection: prevalence of observed ARD is increasing – up to 12% in the latest available reports. Our study shows significant difference in aortic root diameter, which is greater in group 1 (3.23 ± 0.41) than group 2 (2.86 ± 0.41) and group 3 (2.90 ± 0.43). This is similar to the data from the study by Cuspidi et al.  which shows that hypertensive patients with aortic root enlargement have more pronounced alterations in cardiac structure and geometry compared with those without the enlargement. ARD therefore appears to be a useful marker of high cardiovascular risk related to TOD.
Based on the results of our study, 76.8% of hypertensive patients had diastolic dysfunction; 67% of them had DD grade I (E < A) and 11% of them had DD grade II (pseudo normal), but other parameters of diastolic dysfunction such as mitral inflow velocity assessed by pulsed-wave Doppler [early mitral inflow velocity (E), late atrial inflow velocity (A), deceleration time (DT)], however, showed no significant difference between hypertensive patient groups. These advance the assumption that we should do TDI to all hypertensive patients during routine echocardiography assessment. This was similar to the study by Soufi Taleb Bendiab et al.  which shows that among 200 hypertensive patients (mean age: 61.7 ± 9.7 years), 155 were overweight, 93 had diabetes, 83 had dyslipidemia, and 109 had uncontrolled high blood pressure. Diastolic dysfunction patterns were observed in 178 (89%) patients. GLS ranged from − 25 to − 11.6% (mean − 16.9 ± 3.2%). Low GLS values (>−17%) were found in 91 (45.5%) patients, 68 with and 23 without LVH.
This study clarified the importance of strain ST-T changes on ECG in hypertensive patients as a predictor of LV systolic dysfunction and the role of speckle tracking on detection of this subtle LV systolic dysfunction before impairment of conventional echocardiographic data. However, there are limitations in this study that should be addressed, such as small study population. Although none of the study patients showed chest pain and a history of coronary artery disease, we could not exclude the possibility that some patients may have coronary artery disease, which might affect our results. Moreover, one of the most important study limitations was that some patients had other risk factors for LV systolic dysfunction other than hypertension such as diabetes mellitus, smoking, and obesity.
| Conclusion|| |
The decrease in longitudinal strain in hypertensive patients with strain ST-T changes on surface ECG suggests possible link between strain ST-T changes and subendocardial dysfunction. 2D-speckle tracking echocardiography helps in the assessment of LV mechanics in asymptomatic hypertensive patients with normal ejection fraction.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]