Study of clinical characteristics and left ventricular dyssynchrony in patients after acute myocardial infarction using gated - Spect imaging

After myocardial infarction, there are many risk factors for death

such as heart failure, arrhythmia, recurrent myocardial infarction,old age,

and diabetes etc. In our study, 13 patients died after myocardial infarction,

accounting for 12.26%, the majority of these occurred within 12 months

after myocardial infarction. This rate is quite similar to that of Vu Thi

Phuong Lan's study on patients with myocardial infarction with 16 out of

139 (11.51%) patients died after myocardial infarction during the followup of 20.5 ± 11.18 months but it is lower than the rate in Fudim’sstudy

(2018) that tracked 1310 patients with coronary artery disease for 7 yearswith more than one-third of the patients died.

In our study, 41 patients had anterior myocardial infarction,

accounting for 38.7%, 44 patients with inferior myocardial infarction,

accounting for 41.5% and 8 cases of combined myocardial infarction

(7.6%,) 9 cases had myocardial infarction without Q waves accounting

for 8.49%. Vu Thi Phuong Lan also studiedpatients after MI and her

study shows that the rate of anterior, posterior and combined myocardial

infarction and non-Q myocardial infarction were 50.4%, 33.1% and 7.3

and 9.3%, respectively. Pham Hoan Tien's study showed that 61.4% of

patients had anterior myocardial infarction, 38.6% with posterior

myocardial infarction.

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ar dyssynchrony in patients with heart failure by Tissue Doppler ultrasound showed that the heart failure group had a higher rate and level of dyssynchrony than the control group and there is a correlation between the degree of dyssynchrony on Tissue Doppler ultrasound with dyspnea level, QRS width and e jection fraction. Mai Hong Son, Le Ngoc Ha (2014) studied 50 patients with 6 coronary artery disease and 30 patients without coronary artery disease in the control group using GSPECT. Results showed that the dyssynchrony indexes of HBW and PSD in the disease group were significantly higher than those in the control group and there was a correlation between the dyssynchrony index and the width of defect area and ejection fraction. Summary of some findings of left ventricular dyssynchrony in patients after myocardial infarction and some existing problems Gated-SPECT is an effective tool in the diagnosisof dyssynchrony. Dyssynchrony indices on Gated-SPECT have good prognosis for MACE and mortality in patients after acute myocardial infarction. In Vietnam, there has not been much research on left ventricular dyssynchronyby Gated-SPECT and no research has evaluated the relationship between dyssynchrony on Gated-SPECT and clinica l and ultrasonic synchronous Tissue Doppler imaging. CHAPTER 2. RESEARCH SUBJECTS AND METHODOLOGY 2.1. Research subjects The study was carried out at 108 Military Central Hospital from October 2014 to December 2018, on a case group of 106 patients after myocardial infarction and the control group of 34 subjects without cardiovascular diseases.  Patient selection criteria: Case group - Having been diagnosed with acute MI (according to World Health Organization standards - 2012) that have passed the acute phase for at least 14 days. - Stable clinical condition, hemodynamics, cardiac enzyme tests returned to normal. - Meeting the criteria for Gated-SPECT imaging according to the guidelines of the American Society of Nuclear Cardiology 2010. Control group - No cardiovascular diseases when having clinical examination, normal results of ECG and echocardiography. - No evidence of myocardial ischemia on myocardial perfusion imaging: radiation defects in each region <2; SRS <4; SSS <4; total perfusion deficit <5%. - No branch block. 7  Exclusion criteria: - Case group or group of patients after MI: those with mechanical complications after MI, severe arrhythmia, previous history of cardiovascular diseases, disagreeing to participate in the study, and bad radiation imaging. - Control group: those with history of cardiovascular diseases, disagreeing to participate in the study, contraindication to SPECT radiography by GSTL and have been taking dipyridamole as instructed by the American Society of Nuclear Cardiology. 2.2. Methodology: - This is a hospital-based, descriptive, cross-sectional case-control study. - Steps to conduct research: + All subjects were interviewed and had clinical examination. + All subjects were assigned to have basic tests of: pulmonary X-ray, 12- lead ECG, basic biochemical test, Cardiac Doppler ultrasound to record basic parameters ofcardiac structure and function including Dd, Ds, EDV, ESV, and EF. + Parameters to evaluate left ventricular dyssynchrony on TSI according to American Society of Echocardiography (2008): When the standard deviation of time reaches the maximum speed of 12 regions in the systole Ts - SD 34.4 ms on TSI, patients have left ventricular dyssynchrony. The biggest difference of time to reach the maximum speed of 12 regional systolic is Ts-Diff and when Ts - Diff ≥ 105 ms on TSI, patients have left ventricular dyssynchrony. + The patient had an Electrocardiographically gated myocardial perfusion SPECT to assess the position, degree of radiation injury, to calculate a summed rest score (SRS), summed stress score (SSS) and the difference between the two phases, to assess the viability of myocardial, structure index and cardiac function including Dd, Ds, EDV, ESV, EF and parameters to evaluate left ventricular dyssynchrony including standard deviation the onset of contraction in more than 600 left ventricular myocardial regions (PSD) andthe interval that 95% of the myocardial regions begin to contract (HBW). The indices of evaluating left ventricular dyssynchrony on Gated-SPECT include: - PSD: OMC standard deviation of myocardial regions (more than 600 OMC) - HBW: interval containing 95% of OMC - HK, HS: Histogram Kurtosus and skewness 8 Assessment of left ventricular dyssynchrony - The control group had 4 indicators assessed with PSD, HBW, HK, and HS - From the mean of PSD and HBW of the control group, we take the threshold of > +2SD of the control group as the threshold of dyssynchrony. Thus, the criteria for assessing the dyssynchrony are when the PSD or HBW exceeds the + 2SD threshold of the control group. 2.3.Data processing Data were processed using STATA 14.2 software. Quantitative variables are expressed as mean (X) and standard deviation (SD), median; Qualitative variables are expressed as percentages. 2.4. Ethics in research The study did not violate ethica l regulations when carrying out biomedica l research. CHAPTER 3. RESEARCH RESULTS The study was conducted on 140 subjects including the research group of 106 patients after MI and the control group of 34 people without cardiovascular diseases. The study subjects were tracked down for at least 12 months after myocardial infarction in the period from October 2014 and December 2018. 3.1. Clinical, laboratory characteristics and left ventricular dyssynchrony using Gated-SPECT in patients after MI 3.1.1 Clinical and laboratory characteristics of the research group The mean age of bothrcase group and control group were quite high with 65.4 ± 10.31 and 62.68 ± 6.42, respectively. The highest age in the research group is 81 years old and the lowest is 49 years old, in the control group the oldest is 79 years old and the youngest is 53 years old. Men accounted for higher percentage in the research group with 83.96% and 16.04%, respectively, compared to 76.47% and 23.53% in the control group. The majority of patients had typical chest pain symptoms upon admission (53.8%), atypica l chest pain accounted for 44.3%, and those without pain was 1.9%.Patients were assessed of heart failure according to New York Heart Association (NYHA) classification with mainly heart failure class II accounting for 52.8%, the rate of severe heart failure NYHA class III, IV was 30.3%. The number of patients in the intervention of phase 1was a relatively high with 58.1%, those with medical treatment was 41.5% and only 0.95% was treated with coronary artery bypass surgery. 9 The most common risk factors are hypertension (66.98%), dyslipidemia (28.3%), smoking (33.02%), obesity (26.42%) and diabetes (24.5%); Among 106 patients after MI, 61 patients had early coronary intervention, accounting for 58.1%; 13 patients died during the 12-month follow-up, accounting for 12.26%. Inferior wall myocardial infarction accounted for the highest rate (41.51%), the anterior wall myocardial infarction accounted for 38.68%, mainly the large anterior MI with 17.92%. The prevalence ò those with combined MI was 7.55% and the prevalence of patients with Non-Q wave MI was 8.49% .6 patients after the MI had wide QRS complex of > 120 ms accounting for 5.7%. The prevalence of those with left branch block was 5.7%. The mean index of left ventricular systolic volume in the disease group after MI is larger than that of the control group with 59.4 ± 31.03; 30.6 ± 4.65, respectively. The average index of left ventricular systolic function in the disease group after MI is lower than that of the control group with 46.8 ± 14.25; 66.6 ± 5.33, respectively. On Tissue Doppler imaging (TDI), the average indices of the standard deviation of time reaches a maximum speed of 12 regions in the systole Ts - SD12 and the largest difference in time reaches the maximum speed of 12 systolic regions Ts - Diff12 are 43.2 ± 22.19; 121.8 ± 49.81, respectively. Of which 60 patients had Ts - SD12 ≥ 34.4 accounting for (56.6%) and 64 patients had Ts - Diff 12 ≥ 105 with 60.4%. 3.1.2 Situation of left ventricular dyssynchrony on Gated-SPECT in the case group Of the 140 patients studied, we performed Dipyridamole-induced stress myocardial perfusion scans (MPS) for 140 patients (100%). For the group of patients after MI, we performed myocardial perfusion scans at the time point of 15.8 ± 1.05 days after acute MI. Table 3.10. Comparison of left ventricular dyssynchrony indices on Gated-SPECT in patients after MI and the control group Indices Patients after MI(n =106) Control group(n =34) p PSD 48.7 ± 19.49 17.5 ± 7.24 <0.05 HBW 154.9 ± 71.97 53.9 ± 15.14 <0.05 Peak 140.3 ± 33.14 135.6 ± 17.36 >0.05 HK 28.7 ± 20.88 23.1 ± 11.91 >0.05 HS 4.2 ± 1.46 4.1 ± 0.95 >0.05 10 The PSD and HBW indices of the patient group after MI are significantly higher than those of the control group. Table 3.11. Parameters evaluating left ventricular dyssynchrony on Gated-SPECT X +2SD of control group Group of patients after MI PSD 31.99 PSD ≥ 31.99 77 % HBW 84.25 HBW ≥ 84.25 81 % Peak 170.28 Peak ≥ 170.28 12 % HK 46.88 HK ≥ 46.88 15 % HS 6.03 HS ≥ 6.03 7 % When taking the X + 2SD threshold of the control group as the abnormal threshold, the disease group had 77% of patients with increasing PSD and 81% of patients with increasing HBW. Table 3.12. Compatibility of diagnosing LVD between HBW and PSD HBW PSD Total Positive(PSD ≥31.99) Negative (PSD <31.99) Positive(≥84.25) 76 5 81 Negative (<84.25) 1 24 25 Total 77 29 106 Compatibility Po = 0.94 k = 0.85 p < 0.05 Pe = 0.62 The observed compatibility of diagnosing LVD on Gated- SPECT between PSD and HBW is 94.3% (100/106) with Kappa coefficient of 0.85. 3.2. Relationship of left ventricular dyssynchrony on Gated-SPECT and some clinical characteristics and echocardiography in patients after MI 3.2.1. Relationship of left ventricular dyssynchrony on Gated-SPECT and some clinical characteristics and echocardiography in patients after MI Table 3.13. Relationship ofparameters of left ventricular dyssynchronyon G-SPECT and gender Parameters Male (n = 89) (X ± SD) Female (n = 17) (X ± SD) p (ranksum test) PSD (o) 48.4± 19.12 50.4 ± 21.92 >0.05 HBW (o) 155.5 ± 72.91 151.9 ± 68.85 >0.05 11 HS 4.1 ± 1.48 4.6 ± 1.34 >0.05 HK 28.3± 21.66 31.2 ± 16.5 >0.05 Peak 137.9± 33.82 153.1 ± 26.58 0.05 There was no statistically significant difference between the dyssynchrony parameters on Gated-SPECT imaging between male and female. Table 3.14. Relationship of left ventricular dyssynchrony indices by age Age group PSD HBW < 50 (n = 6) 54 ± 19.92 163.2± 60.32 50 -59 (n = 26) 53.8 ± 18.97 170.1± 74.93 60 – 69 (n = 31) 51.8± 18.99 176.3± 75.35 ≥ 70 (n = 43) 42.6± 19.11 129.3 ± 62.92 p (test for trend) < 0.05 < 0.05 There are significant differences between the PSD and HBW indices among age groups. Table 3.15. Relationship of parameters of left ventricular dyssynchrony andheart failure Parameters HF (n = 88) (X ± SD) WithoutHF(n = 18) (X ± SD) p PSD 76.3 ± 15.95 43.8 ± 15.64 <0.05 HBW 241.5 ± 66.43 139.6 ± 61.49 <0.05 HK 36.4 ± 18.66 27.4 ± 21.06 <0.05 HS 4.91 ± 1.37 4.1 ± 1.45 <0.05 Peak 155.3 ± 46.22 137.7 ± 29.8 >0.05 LVD 88 (100%) 13 (72.22%) <0.05 The indices of evaluating left ventricular dyssynchrony (LVD) on Gated-SPECT such as PSD, HBW, HS, and HK in the group of patients with heart failure had higher average values than those in the group of patients without clinical heart failure. 12 Figure 3.3. HBW and PSD indices according to NYHA heart failure classification The indices of HBW, PSD increased significantly with the severity of heart failure according to NYHA classification. Table 3.17. Relationship of indices of left ventricular dyssynchrony on Gated-SPECT and treatment methodsfor patients after MI Indices Coronary intervention (n = 61) (X ± SD) Internal medical treatment (n = 44) (X ± SD) p PSD 45.9 ± 17.18 52.9 ± 22.07 < 0.05 HBW 146.9 ± 67.24 167.3 ± 77.69 <0.05 HK 29.9 ± 24.29 27.2 ± 15.4 >0.05 HS 4.2 ± 1.62 4.3 ± 1.25 >0.05 Peak 145.7 ± 34.45 132.9 ± 30.46 < 0.05 *Mann -whitney; **prtest The value of the PSD and HBW indices in the MI group treated with coronary artery disease in stage one was significantly lower than those of the group treated with internal medicine. 3.2.2. Relationship between LVD index and characteristics of Gated- SPECT and ultrasound. Table 3.19. Relationship of PSD, HBW and EF indices on GSPECT Indices EF ≤ 40% EF> 40%. p* PSD 66.2 ± 16.19 41.8 ± 16.13 < 0.05 HBW 219.2 ± 61.12 129.6 ± 59.22 < 0.05 0 1 0 0 2 0 0 3 0 0 4 0 0 s p e c t_ h b w 2 1 2 3 4 2 0 4 0 6 0 8 0 1 0 0 s p e c t_ p s d 1 2 3 4 13 Patients after myocardial infarction withEF ≤ 40% had a higher value of PSD and HBW than those with EF> 40%. Figure 3.2. Correlation of EF and PSD and HBW There is a linear inverse correlation, the degree of tightness between left ventricular ejection fraction (EF%) and PSD and HBW. Table 3.21. Relationship between LVD indices and radiation defects on Gated-SPECT Perfusion point n PSD HBW Mean p Mean p SRS ≤ 13 65 41.27 ± 16.57 <0.05 128.66 ± 64.42 <0.05 > 13 41 60.44 ± 18.09 196.63 ± 63.66 SSS ≤ 13 50 40.58 ± 15.95 <0.05 130.52 ± 66.27 <0.05 >13 56 55.93 ± 19.64 176.77 ± 70.35 SDS ≥7 14 448.8 ± 23.17 > 0.05 145.5 ± 71.51 > 0.05 <7 92 48.7 ± 19.03 156.4 ± 72.32 The group of patients with SSS or SRS score>13 had significantly higher PSD and HBW than patients with SSS or SRS score <13. Table 3.22. Relationship between LVD indices and defects on Gated- SPECT 2 0 4 0 6 0 8 0 1 0 0 G iá t r ị s p e c t- e f 20 40 60 80 100 Giá t rị spect-psd Giá t rị spect-ef Đường hồi quy (spect-ef = 76.36 - 0.56*spect-psd, R-square=0.57) (r =-0.77, p<0.01) 2 0 4 0 6 0 8 0 1 0 0 G iá tr ị s p e c t- e f 0 100 200 300 400 G iá t rị spect-hbw Giá t rị sspect-ef Đường hồi quy (spect -ef= 70.83 - 0.14*spect-hbw, R-square=0.49) (r =-0.7494, p<0.01) 14 Indices Cardiac muscle condition p Reversible defect (n = 97) Fixed difect (n = 62) PSD 43.2 ± 16.39 55.1 ± 20.99 < 0.05 HBW 138.9 ± 62.56 173.6 ± 78.13 < 0.05 HK 28.7 ± 22.71 28.7 ± 18.76 > 0.05 HS 4.2 ± 1.49 4.2 ± 1.44 > 0.05 Peak 141.1 ± 36.5 139.4 ± 29.09 > 0.05 LVD 41 (42.27%) 62 (100%) < 0.05 Both the PSD and HBW indices in the group with fixed defect of cardiac myocardial area were significantly higher than those in the reversible defect group. Table 3.23. Relationship of indices to evaluate LVD and left ventricularend diastolic volume on Gated-SPECT Indices ESV > 70ml (n =25) ESV ≤ 70ml (n =81) p (fisher exact) PSD (o) 67.4 ± 14.03 42.9 ± 17.2 < 0.05 HBW (o) 218.6 ± 59.3 135.3 ± 63.92 < 0.05 LVD 25 (100%) 57 (70.4%) < 0.05 The group of patients with ESV>70ml had significantly higher PSD and HBW values than the group with normal ESV. Figure 3.10. Correlation graph between PSD on GSPECT and Ts - SD 12 and Ts - Diff 12 on TSI 0 5 0 1 0 0 G iá t rị t s s d 1 2 20 40 60 80 100 Giá trị spect-psd Giá trị tssd12 Đường hồi quy (tssd12= 13 + 0.62*spect-psd, R-square=0.3) (r =0.57, p<0.01) 0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 G iá t rị t s d if f1 2 20 40 60 80 100 Giá trị spect-psd Giá trị tsd iff12 Đườn g hồi quy (tsd iff12= 46 .99 + 1.54*spect-psd, R-square=0.36) (r =0.6391, p<0.01) 15 There is a positive linear correlation between the PSD and the standard deviation of time to reach the maximum speed of 12 regions in the systolic (Ts - SD 12) (r = 0.57; p <0.01) and Ts -Diff (Ts - Diff 12) with r = 0.64; p <0.01. Figure3.11.Correlation between HBW on GSPECT and Ts - SD 12 and Ts - Diff 12 on TSI There is a moderate linear positive correlation between the interval during which 95% of the myocardial region starts contracting or the interval containing 95% of the OMC score (HBW) with the standard deviation of time reaching the maximum velocity of 12 inner regions in systole (Ts - SD 12) with r = 0,5271; p <0.01 and maximum time difference reaches maximum velocity of 12 Ts-Diff in systole(Ts - Diff 12) with r = 0.6; p <0.01. Table 3.25. Relationship of LVD parameters on Gated-SPECT and TSI ultrasound `Gated SPECT Ultrasound Total Positive Negative Positive 64 18 82 Negative 1 23 24 Total 65 41 106 Compatibility Po = 0.82 k = 0.59 p < 0.05 Pe = 0.56 The observed compatibility for diagnosing left ventricular dyssynchrony assessed by Gated-SPECT and Tissue Doppler ultrasound was 87/106 (82.1%); Kappa coefficient equals to 0.59 with p <0.05. 0 5 0 1 0 0 G iá t rị t s s d 1 2 0 100 200 300 400 Gi á trị spect-phbw Giá trị tssd12 Đường hồi quy (tssd12= 20.5 + 0.15*spect-phbw, R-square=0.23) (r =0.5271, p< 0.01) 0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 G iá t r ị ts d if f1 2 0 100 200 300 400 Giá trị spect-phbw Giá t rị tsdi ff12 Đường hồi quy (tsd iff12 =63 .28 + 0.38*spect-phbw, R-square=0.3 ) (r =0.6021, p<0.01) 16 3.2.3. Relationship of LVD indices on Gated-SPECT and mortality complications of patients after MI Table 3.26. Indices of dyssynchrony and mortality complications Indices Dead(n = 13) (X ± SD) Alive(n = 93) (X ± SD) p PSD 71.6 ± 19.66 45.5 ± 17.28 < 0.05 HBW 216.9 ± 64.65 146.3 ± 18.1 < 0.05 HK 46.1 ± 30.51 26.3 ± 18.1 < 0.05 HS 5.4 ± 1.8 4.1 ± 1.34 0.05 Peak 157 ± 47.51 137.9 ± 30.23 > 0.05 LVD 13(100%) 69(74.19%) < 0.05 The indices of assessing left ventricular dyssynchrony on Gated- SPECT such as PSD, HBW, HS, and HK in the group of patients with mortality had higher average indices than those in the group of survivors after MI. Figure 3.12. ROC curve of LVD index on Gated-SPECT and ultrasound predicting mortality after MI PSD and HBW on Gated-SPECT are valid for predicting fatal complications with large area under the ROC curve from 0.7 to 0.8. HK and HS also had a lower predictive of fatal complications with an area under the curve of 0.7. Ts - SD and Ts - Diff on TSI ultrasound are also predicted to have an area under the ROC curve of above 0.7. 0. 00 0. 25 0. 50 0. 75 1. 00 S en si tiv ity 0.00 0.25 0.50 0.75 1.00 1-Specificity spect_psd ROC area: 0.8284 spect_hbw2 ROC area: 0.7725 spect_hs ROC area: 0.7242 spect_hk ROC area: 0.7477 tdi_tssd12 ROC area: 0.7936 tdi_tsdiff12 ROC area: 0.7622 Reference 17 Table 3.27. Dyssynchrony indices predicting mortality Indices AUC Cut- off Sensitivity(%) Specificity(%) PSD 0.8284 53.5 85 68 HBW 0.7725 158.5 85 65 HK 0.7477 31.5 69 75 HS 0.7242 5.8 54 87 TS - SD12 0.7936 47.5 77 73 TS - DIFF12 0.7622 131.5 77 66 PSD and HBW are very valuable for predicting mortality, with areas under the AUC curve of 0.83 and 0.77, respectively. The indices of HK, HS are also valid for predicting mortality but at a lower level. Figure 3.13. Kapplan Meier survival curve predicts mortality according to the PSD and HBW threshold Patients after MI had PSD of above 53.5 are likely to have fatal complications than those with PSD of under 53.5. Patients with HBW of over 158.5 had more fatal complications than patients with HBW of under 158.5. 0 .0 0 0 . 2 5 0 .5 0 0 .7 5 1 .0 0 0 5 10 15 ana lysis time spect-psd dưới ngưỡn g sp ect-psd trên ngưỡ ng 0 .0 0 0 .2 5 0 . 5 0 0 .7 5 1 .0 0 0 5 10 15 anal ysis tim e phbw dưới ngưỡng phbw trên ngưỡng 18 Table 3.1. Mortality risk according to PSD threshold Factors PSD threshold on SPECT Total ≥ 53.5 < 53,5 Dead Yes 11 2 13 No 30 63 93 Total 41 65 106 Risk 0.268 0,031 0.123 Risk ratio(95%CI) 8.72 (2.04 - 37.36) Patients with PSD of over 53.5 were 8.72 times more likely to have mortality risk (CI 95% from 2.04 - 37.36) than patients with PSD of less than 53.5. Table 3.2. Mortality risk according toHBW threshold Factors HBW threshold on SPECT Total ≥ 158.5 <158.5 Dead Yes 11 2 13 No 33 60 93 Total 44 62 106 Risk 0.25 0,032 0.123 Risk ratio(95%CI) 7.75 (1.81 - 33.25) Patients with HBW of over 158.5 were 7.75 times more likely to mortality risk (CI 95% from 1.81 - 33.25) than patients with HBW of less than 158.5. CHAPTER 4. DISCUSSIONS 4.1. Clinical, laboratory characteristics and left ventricular dyssynchrony using Gated-SPECT in patients after MI 4.1.1. Clinical and laboratory characteristics of the research group Our study included 106 patients after MI with the mean age of 65.4 ± 10.31 years; 83.96% of whom are men and 34 subjects in the control group with the mean age of 62.68 ± 6.42 and 76,47% of whom are men. This meets the requirements set out about the compatibility between the research group and control group in the disease-control descriptive study. The gender ratio in our study is s imilar to that of Vu Thi Phuong Lan (2002) with 85.6% of men. The mean age of patients after MI in our study was 65.4 ± 10.31, 69.82% of which aged 60 and older, only 5.66% of patients under 50 years old. In our study, most patients after MI had symptoms of chest pain during acute myocardial infarction, accounting for more than 98%,in which many patients with atypical chest pain accounted for 44.3%. 19 In our study, the majority of patients had an NYHA score of 2 or higher, half of whom have an NYHA score of 2; one fourth of patients with NYHA score of 3; 5 patients had NYHA score of 4 at the time of admission. After myocardial infarction, there are many risk factors for death such as heart failure, arrhythmia, recurrent myocardial infarction,old age, and diabetes etc. In our study, 13 patients died after myocardial infarction, accounting for 12.26%, the majority of these occurred within 12 months after myocardial infarction. This rate is quite similar to that of Vu Thi Phuong Lan's study on patients with myocardial infarction with 16 out of 139 (11.51%) patients died after myocardial infarction during the follow- up of 20.5 ± 11.18 months but it is lower than the rate in Fudim’sstudy (2018) that tracked 1310 patients with coronary artery disease for 7 years- with more than one-third of the patients died. In our study, 41 patients had anterior myocardial infarction, accounting for 38.7%, 44 patients with inferior myocardial infarction, accounting for 41.5% and 8 cases of combined myocardial infarction (7.6%,) 9 cases had myocardial infarction without Q waves accounting for 8.49%. Vu Thi Phuong Lan also studiedpatients after MI and her study shows that the rate of anterior, posterior and combined myocardial infarction and non-Q myocardial infarction were 50.4%, 33.1% and 7.3 and 9.3%, respectively. Pham Hoan Tien's study showed that 61.4% of patients had anterior myocardial infarction, 38.6% with posterior myocardial infarction. In our study, the group of patients with myocardial infarction had Dd and Ds of 49.7 ± 6.79 and 33.88 ± 7.84, EDV and ESV of 129.18 ± 38.26 ml and 59.42 ± 31.03, much higher than those of the control group. This result is quite similar to that of Vu Thi Phuong Lan (2012) with Dd, Ds of 51.2 ± 6.7 and 36.3 ± 7.5 and EDV, ESV of 128.8 ± 39.3 and 59.7 ± 30.7, respectively. Ejection fraction of patients after MI is significantly lower than that of the control group with p <0.05. The percentage of patients with ejection fraction EF <50% on ultrasound in the group of patients after MI is 66.9%. This difference may be due to patient characteristics, severity of infarction, rate of earlyrevascularization intervention in the group of patients after MI in different studies. In our study, all patients underwent ultrasound TSI to evaluate dyssynchrony. The results show that mean Ts - SD 12 is 43.16 ± 22.19 ms, mean Ts - Diff 12 is 121.81 ± 49.81 ms. This result is similar to the study of Alam (2015) in patients after myocardial infarction with values 20 of Ts -

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