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 Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 8  |  Issue : 2  |  Page : 93-97

Left ventricular systolic function assessment with two-dimensional strain imaging among patients with rheumatic mitral stenosis


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 Submission05-Mar-2020
Date of Decision06-Jun-2020
Date of Acceptance10-Jun-2020
Date of Web Publication4-Aug-2020

Correspondence Address:
Dr. Amresh Kumar Singh
Flat 302 Faculty Residence, Dr. RMLIMS, Vibhuti Khant, Lucknow, Uttar Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/heartindia.heartindia_10_20

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  Abstract 


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 Top


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%.[1],[2]

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.[3],[4] TDI and Doppler strain are characterized by the limitations of angle dependence, limited spatial resolution, and deformation analysis in one dimension.[4],[5] 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.[6],[7] 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

  1. To study the LV systolic function in rheumatic MS patient by 2D strain imaging
  2. To find the relation to LV systolic dysfunction and the presence of arrhythmia.



  Materials and Methods Top


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.

Inclusion criteria

Patients previously diagnosed to have predominant rheumatic MS and patients aged <55 years were included in the study.

Exclusion criteria

  1. Patients aged >55 years
  2. Diabetic patients (diagnosed by fasting and postprandial blood sugar)
  3. Hypertensive patients (diagnosed by sphygmomanometer)
  4. Patients known to have ischemic heart disease
  5. Patients known to have any type of cardiomyopathies
  6. Patients known to have myocarditis
  7. Patients with significant aortic valve disease
  8. Patients with moderate or severe mitral regurgitation
  9. Patients with prosthetic valve.


Statistical analysis

  • 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 Top


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].
Figure 1: Distribution of cases with atrial fibrillation

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Figure 2: Mean left atrial diameter of cases

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Table 1: Distribution of echocardiographic parameter among study groups

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Table 2: Distribution of echocardiographic parameter among case groups

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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 Top


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.[8],[9]

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.[1],[9]

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.[4],[10]

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).[11]

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).[10],[12]

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.[8] 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.[13] Moreover, the inflammatory process, which is more intense in association with AF than with sinus rhythm, has the potential to impair ventricular performance.[14]

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).[15]

Limitation

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 Top


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

Nil.

Conflicts of interest

There are no conflicts of interest.

Ethical Approval

The ethical approval was obtained from the Government Medical college Trivandrum.



 
  References Top

1.
Henein MY, Sheppard M, Pepper J, Rigby M. Mitral valve. In: Clinical Echocardiography. Springernature Switzerland: Springer; 2004. p. 1-30.  Back to cited text no. 1
    
2.
Gaasch WH, Folland ED. Left ventricular function in rheumatic mitral stenosis. Eur Heart J 1991;12 Suppl B: 66-9.  Back to cited text no. 2
    
3.
Kuecherer HF, Kee LL, Modin G, Cheitlin MD, Schiller NB. Echocardiography in serial evaluation of left ventricular systolic and diastolic function: Importance of image acquisition, quantitation, and physiologic variability in clinical and investigational applications. J Am Soc Echocardiogr 1991;4:203-14.  Back to cited text no. 3
    
4.
Garcia MJ, Rodriguez L, Ares M, Griffin BP, Klein AL, Stewart WJ, et al. Myocardial wall velocity assessment by pulsed wave Doppler tissue imaging: Characteristic findings in normal subjects. Am Heart J 1996;132:648-56.  Back to cited text no. 4
    
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Marwick TH. Measurement of strain and strain rate by echocardiography: Ready for prime time? J Am Coll Cardiol 2006;47:1313-27.  Back to cited text no. 5
    
6.
Thomas G. Response to “non-Doppler two-dimensional strain imaging by echocardiography-from technical considerations to clinical applications”. J Am Soc Echocardiogr 2007;20:1020.  Back to cited text no. 6
    
7.
Hashimoto I, Li X, Bhat AH, Jones M, Zetts AD, Sahn DJ. Myocardial strain rate is a superior method for evaluation of left ventricular subendocardial function compared with tissue Doppler imaging. J Am CollCardiol 2003;42:1574-83.  Back to cited text no. 7
    
8.
Buyukkaya S, Buyukkaya E, Arslan S, Aksakal E, Sevimli S, Gundogdu F, et al. Evaluation of left ventricular long-axis function in cases of rheumatic pure mitral stenosis with atrial fibrillation. Tex Heart Inst J 2008;35:22-7.  Back to cited text no. 8
    
9.
Lee YS, Lee CP. Ultrastructural pathological study of left ventricular myocardium in patients with isolated rheumatic mitral stenosis with normal or abnormal left ventricular function. Jpn Heart J 1990;31:435-48.  Back to cited text no. 9
    
10.
Ozdemir AO, Kaya CT, Ozcan OU, Ozdol C, Candemir B, Turhan S, et al. Prediction of subclinical left ventricular dysfunction with longitudinal two-dimensional strain and strain rate imaging in patients with mitral stenosis. Int J Cardiovasc Imaging 2010;26:397-404.  Back to cited text no. 10
    
11.
Younan H. Role of two dimensional strain and strain rate imaging in assessment of left ventricular systolic function in patients with rheumatic mitral stenosis and normal ejection fraction. Egypt Heart J 2015;67:193-8.  Back to cited text no. 11
    
12.
Simşek Z, Karakelleoǧlu S, Gündoǧdu F, Aksakal E, Sevimli S, Arslan S, et al. Evaluation of left ventricular function with strain/strain rate imaging in patients with rheumatic mitral stenosis. Anadolu Kardiyol Derg 2010;10:328-33.  Back to cited text no. 12
    
13.
Shinbane JS, Wood MA, Jensen DN, Ellenbogen KA, Fitzpatrick AP, Scheinman MM. Tachycardia-induced cardiomyopathy: A review of animal models and clinical studies. J Am Coll Cardiol 1997;29:709-15.  Back to cited text no. 13
    
14.
Aviles RJ, Martin DO, Apperson-Hansen C, Houghtaling PL, Rautaharju P, Kronmal RA, et al. Inflammation as a risk factor for atrial fibrillation. Circulation 2003;108:3006-10.  Back to cited text no. 14
    
15.
Hady BM, Al-Shahawy ES, Fereig HM. LV function assessment in mitral stenosis patients with or without atrial fibrillation; Tissue Doppler and strain imaging. AAMJ 2011;9:379-93.  Back to cited text no. 15
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]



 

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