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.
27 trang |
Chia sẻ: honganh20 | Ngày: 18/03/2022 | Lượt xem: 408 | Lượt tải: 2
Bạn đang xem trước 20 trang tài liệu Study of clinical characteristics and left ventricular dyssynchrony in patients after acute myocardial infarction using gated - Spect imaging, để xem tài liệu hoàn chỉnh bạn click vào nút DOWNLOAD ở trên
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 -
Các file đính kèm theo tài liệu này:
- study_of_clinical_characteristics_and_left_ventricular_dyssy.pdf