|Year : 2020 | Volume
| Issue : 2 | Page : 93-97
Left ventricular systolic function assessment with two-dimensional strain imaging among patients with rheumatic mitral stenosis
Amresh Kumar Singh1, Amit Kumar2, SK Vijay1, Sunitha Vishwanathan3
1 Department of Cardiology, Dr. RMLIMS, Lucknow, Uttar Pradesh, India
2 Department of Medicine, Government Medical College, Azamgarh, Uttar Pradesh, India
3 Department of Cardiology, Government Medical College, Thiruvananthapuram, Kerala, India
|Date of Submission||05-Mar-2020|
|Date of Decision||06-Jun-2020|
|Date of Acceptance||10-Jun-2020|
|Date of Web Publication||4-Aug-2020|
Dr. Amresh Kumar Singh
Flat 302 Faculty Residence, Dr. RMLIMS, Vibhuti Khant, Lucknow, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Introduction: Two-dimensional (2D) strain is a novel technique which evaluates left ventricular (LV) systolic functions more objectively and quantitatively and does not have the limitations seen in ejection fraction (EF), tissue Doppler imaging, and Doppler strain. In this study, we aimed to evaluate the role of 2D strain in the assessment of LV systolic function and the relationship between the presence of atrial fibrillation (AF) and LV dysfunction in patients with mitral stenosis (MS).
Materials and Methods: This study is a cross-sectional study. The 2D strain was obtained from LV apical LAX, 4C, and 2C view. Peak LV longitudinal systolic strain was calculated for apical LCX, 4C, and 2C view, and global LV systolic strain was calculated by averaging the three apical views.
Results: A total of thirty patients were enrolled in the study. They included 24 (80%) females and 6 (20%) males. There were 11 patients (36.7%) had AF and 21 patients (63.3%) had sinus rhythm. There were mean mitral valve area 1.17 cm2 (by planimetry) and 1.19 cm2 (by pressure half-time), mean mitral valve gradient 12.0 mmHg, mean peak gradient 22 mmHg, and mean right ventricular systolic pressure (50.6 vs. 37.4 mmHg) compared to sinus group. In this study, the mean ALAX LSS (−15.12), mean A4C LSS (−14.65), mean A2C LSS (−13.89), and mean GLOBAL LSS (−14.52) were statistically significant (P < 0.001) lower than the control group. Among AF groups, there were statistically significant (P < 0.05) lower A2C LSS and GLOBAL LSS, but there was no significant difference in ALAX LSS and A4C LSS in both groups.
Conclusion: Despite normal LV dimensions and EF, there was a highly significant lower (P < 0.001) global longitudinal systolic strain (GLSS) in MS patients compared to healthy controls. Patients with AF had significantly lower GLSS value (P < 0.05) than the sinus rhythm group among patients with MS.
Keywords: Atrial fibrillation, left atrium, left ventricle, mitral stenosis
|How to cite this article:|
Singh AK, Kumar A, Vijay S K, Vishwanathan S. Left ventricular systolic function assessment with two-dimensional strain imaging among patients with rheumatic mitral stenosis. Heart India 2020;8:93-7
|How to cite this URL:|
Singh AK, Kumar A, Vijay S K, Vishwanathan S. Left ventricular systolic function assessment with two-dimensional strain imaging among patients with rheumatic mitral stenosis. Heart India [serial online] 2020 [cited 2020 Sep 24];8:93-7. Available from: http://www.heartindia.net/text.asp?2020/8/2/93/291351
| Introduction|| |
The prevalence of left ventricular (LV) dysfunction with mitral stenosis (MS) is controversial.
Much of the research performed on this topic is several decades old secondary because of the declining prevalence of rheumatic heart disease. Although it is generally believed that LV contractility is normal in most cases of MS, some studies have suggested otherwise. Several studies have reported that the prevalence of a reduced LV ejection fraction (EF) in patients with pure MS may be as high as 33%.,
In the assessment of LV systolic function, a number of imaging techniques, such as echocardiography, magnetic resonance imaging, scintigraphy, and computed tomography, have been used. In the echocardiographical assessment of LV function, the EF, tissue Doppler imaging (TDI), Doppler strain, and two-dimensional (2D) strain have been widely used. EF is the most widely used index of contractile function, but due to the visual component, the assessment of endocardial excursion is subjective and has high inter-observer variability., TDI and Doppler strain are characterized by the limitations of angle dependence, limited spatial resolution, and deformation analysis in one dimension., The 2D strain is a novel technique which evaluates LV systolic functions more objectively and quantitatively and does not have the limitations seen in EF, TDI, and Doppler strain; thus, it has become more commonly used in recent years., In this study, we aimed to evaluate the role of 2D strain in the assessment of subclinical LV systolic dysfunction and the relationship between the presence of atrial fibrillation (AF) and LV dysfunction in patients with MS.
Aims and objectives
- To study the LV systolic function in rheumatic MS patient by 2D strain imaging
- To find the relation to LV systolic dysfunction and the presence of arrhythmia.
| Materials and Methods|| |
This study is a cross-sectional study. There were a total of thirty patients included in the study, in which 24 were female and 6 were male.
All patients are evaluated with detailed clinical history, physical examination, chest X-ray, electrocardiography, routine blood test, fasting and postprandial blood sugar, erythrocyte sedimentation rate, C-reactive protein, and antistreptolysin O titer (to exclude active carditis).
Echocardiographic study was done by GE healthcare vivid E9 (New york, USA) in parasternal long axis, parasternal short axis, apical four-chamber view, and apical two-chamber view to measure left atrial (LA) and LV dimensions. EF was calculated by M mode of short-axis view. The mitral valve area (MVA) was calculated by planimetry and the pressure half-time (PHT) method.
2D strain was obtained from LV apical LAX, A4C, and A2C view. Peak LV longitudinal systolic strain was calculated for apical LCX, 4C, and 2C view, and global LV systolic strain is calculated by averaging the three apical views.
Patients previously diagnosed to have predominant rheumatic MS and patients aged <55 years were included in the study.
- Patients aged >55 years
- Diabetic patients (diagnosed by fasting and postprandial blood sugar)
- Hypertensive patients (diagnosed by sphygmomanometer)
- Patients known to have ischemic heart disease
- Patients known to have any type of cardiomyopathies
- Patients known to have myocarditis
- Patients with significant aortic valve disease
- Patients with moderate or severe mitral regurgitation
- Patients with prosthetic valve.
- Data were collected, coded, and translated to English to facilitate data manipulation and double entered into Microsoft Access, and data analysis was performed using SPSS software 16 version (Chicago, USA)
- The results were presented in mean +_ standard deviation and percentage.
- For quantitative parametric data
- Independent Student'st- test was used to compare measures of two independent groups of quantitative data.
- For qualitative data
- The chi-square test was used to compare the categorical vareables at the baseline between cases control.
- The level P ≤ 0.05 was considered the cutoff value for significance.
| Results|| |
A total of thirty cases were enrolled in this study. It includes 24 (80%) females and 6 (20%) males. The mean age was 39 years for the case and 42 years for control groups. The history of rheumatic fever was found in 17 (56.6%) cases. Among thirty cases, 11 (36.7%) patients were in AF and 19 (63.3%) were in sinus rhythm [Figure 1]. In this study, there was no significant difference (P > 0.05) in systolic and diastolic blood pressure, LVIDd, LVIDs, EF, and fractional shortening among the two groups. The mean LA diameter (4.34 cm) was significantly larger in cases than the control group (P < 0.001) [Figure 2] and [Table 1]. There were mean MVA 1.17 cm2 (by planimetry) and 1.19 cm2 (by PHT), mean mitral valve gradient 12.0 mmHg, mean peak gradient 22 mmHg [Table 2], mean Wilkin's score 8.1, mean right ventricular (RV) systolic pressure 42.33 mmHg, and mean pulmonary artery pressure 27.65 mmHg. Despite normal LV dimensions and EF by M mode, in this study, the mean ALAX LSS (−15.12), mean A4C LSS (−14.65), mean A2C LSS (−13.89), and mean global LSS (−14.52) were statistically significant (P < 0.001) lower than the control group [Table 3].
|Table 3: Distribution of two-dimensional echo strain parameter among study groups|
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However, among the AF group, there were statistically significant (P < 0.05) high mean Wilkin's score (9.3 vs. 7.4), mean LA diameter (4.7 vs. 4.1 cm), mean pulmonary artery pressure (33 vs. 24.5 mmHg), and mean RV systolic pressure (50.6 vs. 37.4 mmHg) compared to sinus rhythm group. There were no significant differences in LVIDd, LVIDs, EF, and fractional shortening between two groups. The mean age was 42.5 years in the AF group compared to 37.4 years in the sinus group (P = 0.1) [Table 4]. In comparison to sinus rhythm, AF patients had statistically significant lower mean A2C LSS (−12.7 vs. −15.6) and mean global LSS (−12.7 vs. −15.6), (P < 0.05). There was no statistically difference in mean ALAX LSS (−13.6 vs. −16.0; P = 0.056) and mean A4C LSS (−12.9 vs. −15.7; P = 0.051) [Table 5].
|Table 4: Distribution of echocardiographic parameter among the atrial fibrillation groups|
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|Table 5: Distribution of two-dimensional echo strain parameter among atrial fibrillation group groups|
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| Discussion|| |
MS most commonly affects females. The status of systolic LV performance in patients with isolated MS is controversial. Potential alterations in LV architecture, as well as loading conditions, may have complex effects on LV ejection performance and muscle function.,
In some patients with long-standing MS, mild-to-modest degrees of the posterobasal regional wall contraction abnormalities may develop and may be attributed to a rigid mitral valve annulus and subvalvular apparatus. Chronic low cardiac output with significantly decreased coronary flow reserves may contribute to diffuse hypokinesia and decreased LV compliance.,
Strain is a measure of fiber shortening, and strain rate measures the rate of deformation. Hence, both of these methods provide complementary data about the global and regional myocardial function. 2D strain imaging may reflect subclinical heart disease and true wall motion that cannot be identified by the TDI-derived strain analysis. However, studies related to the use of 2D strain, a more objective technique in the diagnosis of LV systolic function in MS, are very limited.,
The study evaluated peak longitudinal LV systolic strain in patients with rheumatic MS and normal LV systolic function. Peak longitudinal LV systolic strain (ALAX-LSS, A4C-LSS, A2C-LSS, and GLSS) was highly significantly decreased in patients with rheumatic MS compared to the control group (<0.001).
Hany Younan studied the role of longitudinal 2D strain and strain rate imaging in the rheumatic mitral stenosis patients with normal ejection fraction in fifty patients. Patients with MS had significantly lower 2D longitudinal LV systolic strain and strain rate compared to the control group (<0.001 and <0.05, respectively).
Ozdemir et al. studied the subclinical LV dysfunction with longitudinal 2D strain and strain rate imaging in patients with MS in sixty patients with mild-to-moderate MS and found that despite normal LV systolic function as assessed by EF (66 ± 8%), the mean global longitudinal strain (GLS) and global longitudinal strain rate were significantly reduced in patients with isolated MS (P < 0.0001). Our study agrees with the same result that despite normal EF (64.8% ± 5.66), the mean GLS is significantly reduced in predominant MS patients (GLSS – 14.52 ± 3.01, P < 0.001).,
In patients with MS and AF, the causative mechanisms of LV dysfunction are not well known due to the small number of studies, but there are some probabilities: for example, the reduction in cardiac output, in association with the acceleration of heart rate and shortening of diastolic time, could cause LV dysfunction, as could chronic myocardial atrophy and fibrosis. Rheumatic involvement of the LV and the LA wall could result both in decreased LV systolic function and AF. Another threat to LV dysfunction is cardiomyopathy due to tachycardia. Moreover, the inflammatory process, which is more intense in association with AF than with sinus rhythm, has the potential to impair ventricular performance.
There are no many 2D strain imaging studies of patients with MS who have AF and unexplained LV dysfunction. Our study compares MS patients with AF to those in sinus rhythm and found that among AF groups, there are statistically significant (P < 0.05) high mean Wilkin's score (9.3 vs. 7.4) and mean LA diameter (4.7 vs. 4.1 cm) compared with sinus rhythm group. There is no significant difference in LVIDD, LVIDS, EF, and FS between the two groups. However, in comparison to sinus rhythm, AF patients have statistically significant (P < 0.05) lower A2C LSS and GLOBAL LSS. There are no significant differences in ALAX LSS and A4C LSS in both groups, but the absolute value was lower than the sinus group.
Bassem M.H. and coworkers evaluated the left ventricular function in rheumatic mitral stenosis patients with or without atrial fibrillation using tissue doppler imaging and strain imaging. Rheumatic mitral stenosis patients had left ventricular systolic as well as diastolic dysfunction irrespective to their basic rhythm. However, Global longitudinal systolic strain (GLSS) values were significantly lower in the AF group compared to the sinus group (GLSS −13.8 vs. −16.6, P < 0.05).
The potential limitation of the present study is the relatively small sample size, so the results may not be generalized. As only standard apical images were obtained, we could only measure longitudinal strain parameters, so neither circumferential nor radial strain and strain rate analysis could be carried out. Our study cases were mostly had normal conventional 2D echocardiographic parameters. We need to follow-up on our patients to detect any deterioration in their LV systolic function.
| Conclusion|| |
Despite normal LV dimensions and EF, there was a highly significant lower (P < 0.001) GLSS in MS patients compared to healthy controls. Patients with AF had significantly lower GLSS value (P < 0.05) than the sinus rhythm group among patients with MS. Hence, 2D strain imaging is a new tool to diagnose subclinical LV systolic dysfunction among patients with MS.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
The ethical approval was obtained from the Government Medical college Trivandrum.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]