Patients with Non-ST-Segment Elevation Myocardial
Infarction Present with More Severe Systolic and
Diastolic Dysfunction Than Patients with
Unstable Angina
Nithima Chaowalit MD*, Ruedeekorn Auesethasak, MD*,
Yingsak Santanakorn MD*, Decho Jakrapanichakul MD*,
Maytinee Kittipovanonth MD*, Srisakul Chirakarnjanakorn MD*
* Division of Cardiology, Department of Medicine, Siriraj Hospital, Faculty of Medicine, Mahidol University,
Bangkok, Thailand
Background: Patients with non ST-segment elevation acute coronary syndrome (NSTEACS) present with diverse clinical,
electrocardiographic, cardiac biomarker, echocardiographic and angiographic characteristics. We sought to determine
whether there was any difference in the indices of left ventricular systolic and diastolic function among subgroups of patients
with NSTEACS.
Material and Method: We studied 121 consecutive patients (mean age 68.6 + 11.3 years, 45% male) with NSTEACS who
underwent comprehensive echocardiography within 48 hours of admission. Two-dimensional and Doppler echocardiography
was performed for the evaluation of left ventricular systolic and diastolic function.
Results: Non ST-segment elevation myocardial infarction (NSTEMI) and unstable angina (UA) were reported in 59% and
41% of patients, respectively. Clinical characteristics (such as age, gender, cardiovascular risk factors, prior myocardial
infarction and revascularization, medication) were not significantly different between patients with NSTEMI and UA. Patients
with NSTEMI were more likely to have wall motion abnormalities and lower left ventricular ejection fraction (p < 0.05) as
compared to those with UA. Diastolic dysfunction was significantly more frequent and more severe in patients with NSTEMI
than in those with UA.
Conclusion: Among patients with NSTEACS, left ventricular systolic and diastolic dysfunction was more frequent and more
severe in patients with NSTEMI that in those with UA. These findings may be used to characterize the sicker group among
patients with NSTEACS.
Keywords: Diastolic dysfunction, Echocardiography, Non ST-segment elevation myocardial infarction, Unstable angina
J Med Assoc Thai 2011; 94 (Suppl. 1): S19-S24
Full text. e-Journal: http://www.mat.or.th/journal
Patients with non ST-segment elevation acute
coronary syndrome (NSTEACS) present with diverse
clinical, electrocardiographic (ECG), cardiac biomarker,
echocardiographic and angiographic characteristics.
Echocardiography has been used for diagnosis and
risk assessment in patients presenting with symptoms
suggestive of myocardial ischemia. Two-dimensional
echocardiography provides the assessment of wall
Correspondence to:
Chaowalit N, Division of Cardiology, Department of Medicine,
Siriraj Hospital, Mahidol University,
Bangkok 10700, Thailand.
Phone: 0-2412-7000 ext. 6104, Fax: 0-2412-7412
E-mail: sincw@mahidol.ac.th
J Med Assoc Thai Vol. 94 Suppl. 1 2011
motion abnormalities and has been used for the
detection of myocardial ischemia and infarction in
patients with acute chest pain syndrome, regardless of
the ECG findings on presentation. Tissue Doppler
imaging (TDI), a recently developed echocardiographic
modality, is useful for the evaluation of left ventricular
(LV) systolic and diastolic function, regardless of
loading conditions. It has several advantages over
conventional echocardiography, including the better
determination of myocardial velocities and a good
correlation with invasive measures of ventricular
systolic and diastolic function such as maximum or
minimum dP/dt and time constant of LV relaxation.
Therefore, the combination of information obtained by
conventional echocardiography and TDI provides the
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comprehensive evaluation of LV function. We sought
to determine whether there was any difference in the
indices of systolic and diastolic function among
subgroups of patients with NSTEACS.
Material and Method
Study Population
Patients with the diagnosis of NSTEACS were
consecutively enrolled into the study. The study was
approved by the ethical committee of Siriraj Hospital.
Patients had to be > 18 years of age and had symptoms
consistent with acute coronary syndrome accompanied
by cardiac biochemical markers or ECG changes.
Patients with Non-ST-segment Elevation Myocardial
Infarction (NSTEMI) were defined as those with positive
cardiac biochemical markers of necrosis accompanied
by ST-segment changes, but without new ST-segment
elevation on the index ECG. Patients with unstable
angina (UA) were those who had ST-T wave changes
on the index ECG, regardless of the presence of chest
pain at the time of the ECG, with normal levels of cardiac
biochemical markers of necrosis. Patients were excluded
from the study if they had a ST-segment elevation
myocardial infarction or new left bundle branch block,
a permanent pacemaker, significant valvular heart
disease, prosthetic valve replacement, underwent
coronary revascularization within 48 hours of admission
or if ECG showed right and left bundle branch block.
Information about conventional coronary risk factors
was obtained. Diabetes mellitus was defined according
to the requirement for treatment with insulin or oral
hypoglycemic agents, or a fasting plasma glucose
> 126 mg/dl on at least two occasions. Hypertension
was defined from the history or an in-hospital systolic
blood pressure > 140 mmHg or diastolic blood
pressure > 90 mm Hg. Patients were considered to have
dyslipidemia if they were receiving lipid-lowering agents
or if their total cholesterol during hospitalization was
> 200 mg/dl, low-density lipoprotein cholesterol > 130
mg/dl or high-density lipoprotein cholesterol < 40 mg/
dl. Family history of premature coronary artery disease
was defined as the presence of coronary artery disease
in a first-degree relative for male age < 55 years or female
< 65 years.
Echocardiography
All patients with NSTEACS underwent
comprehensive echocardiography within 48 hours
of admission. Echocardiographic examination consisted
of two-dimensional, M-mode, conventional Doppler,
and TDI measurements. All echocardiographic
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parameters were reported as the average of the values
of at least 3 consecutive beats. The echocardiographers
(NC, RA and YS) were blinded to the final diagnosis.
LV ejection fraction was determined using the Modified
Simpson’s rule (biplane). LV systolic dysfunction was
defined as the LV ejection fraction < 40%. LV diastolic
function was evaluated by Doppler echocardiography
of transmitral flow velocities and TDI of medial mitral
annulus. Pulse-wave Doppler study of mitral valve
inflow was determined by placing sample volume at
the tip of mitral leaflets in the apical 4-chamber view.
Peak early (E) and late diastolic velocities of mitral inflow
and deceleration time of E were then measured. The
TDI determination of diastolic function was performed
in apical 4-chamber view with the sample volume at the
septal aspect of mitral annulus. Longitudinal early (E’)
and late diastolic myocardial velocities were measured.
E/E’ ratio was defined as high if E/E’ ratio was > 15,
indicating the elevation of LV end-diastolic pressure.
Left atrial volume (LAV), indicating the chronicity of
diastolic dysfunction, was measured using the arealength biplane method. LA enlargement was defined as
LAV index > 32 ml/M2.
Statistical Analysis
Categorical variables were summarized
as percent (%) of patients, and continuous variables
as mean + standard deviation. Comparison between
groups was based on the independent sample t-test
and the Mann-Whitney U test for continuous variables
and Pearson’s Chi-square test for categorical variables.
Data were analyzed using SPSS for Windows (Version
11.5, SPSS Inc., Chicago, Illinois, USA). A p-value
< 0.05 was considered statistically significant.
Results
There were 121 patients with NSTEACS
enrolled in the study. NSTEMI and UA were diagnosed
in 71 (59%) and 50 (41%) patients, respectively. The
mean age was 68.6 + 11.3 years and 45% were male
gender. Cardiovascular risk factors were described
as hypertension in 85%, dyslipidemia in 67%, diabetes
mellitus in 64%, smoking in 11% and family history
of premature coronary artery disease in 2% of
patients. Prior myocardial infarction and coronary
revascularization were reported in 21% and 25% of
patients, respectively. Dyspnea at presentation and/or
clinical heart failure (Killip class > 1) was presented in
61% of patients. Clinical characteristics (such as age,
gender, cardiovascular risk factors, prior myocardial
infarction and revascularization, medication) were not
J Med Assoc Thai Vol. 94 Suppl. 1 2011
significantly different between patients with NSTEMI
and UA (Table 1).
Echocardiographic Findings
The mean LV ejection fraction was 55.2 +
14.6%. LV systolic dysfunction and regional wall
motion abnormalities were present in 17% and 62% of
patients, respectively. LV systolic dysfunction was
more prevalent in patients with NSTEMI than in
those with UA (22.5% and 8.0% of patients, respectively,
p = 0.03). Patients with NSTEMI had lower LV ejection
fraction than those with UA (51.8 + 14.9% vs. 60.2 +
12.9%, p = 0.002). Diastolic function was categorized
as normal, grade 1 = abnormal relaxation, grade 2 =
pseudonormalization pattern and grade 3 = restrictive
filling pattern in 5%, 67%, 22% and 6% of patients,
respectively. High E/E’ ratio, indicating the elevation of
LV end-diastolic pressure, was found in 66% of patients.
The mean LAV and LAV index were 64.4 + 20.8 ml and
39.8 + 13.0 ml/M2, respectively. LA enlargement was
detected in 71% of patients. Diastolic dysfunction was
more frequent and more severe in patients with NSTEMI
than in those with UA as shown in Table 2. Furthermore,
most of parameters showing diastolic dysfunction (E’,
E/E’ and deceleration time) remained more severe in
patients with NSTEMI after adjusted for LV ejection
fraction (p < 0.001).
Discussion
The present study shows the differences in
the echocardiographic findings among the subgroups
of patients with NSTEACS. The echocardiographic
characteristics in patients with NSTEMI and UA were
significantly different both in term of frequency and
severity of LV systolic and diastolic dysfunction.
Among the subgroups of patients with
NSTEACS, patients with NSTEMI represent the
more severe form of the underlying coronary artery
occlusion and myocardial injury than those with UA.
This may lead to a variety of clinical and laboratory
findings. Previous studies have shown several
parameters used to risk stratify patients with
NSTEACS, such as clinical, ECG, cardiac biomarkers,
echocardiographic and angiographic characteristics.
Table 1. Baseline characteristics of patients with NSTEMI and UA
Age (year)
Male gender
Diabetes mellitus
Hypertension
Dyslipidemia
Smoking
Prior myocardial infarction
Prior revascularization
NSTEMI
UA
p-value
69.1 + 10.6
34 (47.9%)
48 (67.6%)
61 (85.9%)
47 (66.2%)
10 (14.1%)
17 (23.9%)
16 (22.5%)
67.8 + 12.4
21 (42.0%)
29 (58.0%)
42 (84.0%)
34 (68.0%)
3 (6.0%)
8 (16.0%)
14 (28.0%)
0.87
0.52
0.28
0.77
0.84
0.16
0.29
0.49
Data are expressed as mean + standard deviation and the number (%) of patients
Table 2. Indices of diastolic function in patients with NSTEMI and UA
E (cm/s)
E’ (cm/s)*
E/E’ ratio*
E/E’ ratio > 15
DT (ms)
LAV (ml)
NSTEMI
UA
p-value
100.3 + 11.8
3.0 (1.0, 15.0)
22.6 (5.7, 68.7)
56 (80)
201.2 + 90.8
67.3 + 20.4
74.6 + 14.3
4.5 (1.0, 18.0)
15.0 (3.1, 49.0)
25 (52)
245.2 + 87.0
60.2 + 20.8
0.03
< 0.001
< 0.001
0.001
0.006
0.05
Data are expressed as mean + standard deviation, median (min, max) and the number (%) of patients. * Compare median using
the Mann-Whitney U test. DT = deceleration time, E = early transmitral flow velocity, E’ = early diastolic septal mitral
annulus velocity, LAV = left atrial volume
J Med Assoc Thai Vol. 94 Suppl. 1 2011
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TIMI risk score is one of the examples for risk
stratification among patients with NSTEACS, using the
combination of various parameters, such as clinical
setting, ST-segment deviation and cardiac marker, to
categorize the risk of death and ischemic events(1).
In the setting of acute coronary syndrome,
echocardiography is of paramount importance in the
diagnosis and prognostication. Losses of myocardial
contractile function/tissue and changes in ventricular
geometry have been described in the setting of acute
coronary syndrome. These abnormalities can modify
LV systolic and diastolic function and furthermore,
affect the clinical course. LV systolic dysfunction
contributes to impaired LV pump function and leads to
mortality and morbidity after acute myocardial
infarction (AMI). Furthermore, LV diastolic dysfunction
after AMI contributes to symptoms and disability
associated with heart failure and even death. LV systolic
function has long been a classic echocardiographic
characteristic in determining the prognosis after
AMI. Several previous studies showed that LV systolic
dysfunction strongly predicted adverse clinical
outcomes, such as mortality and heart failure, after
AMI(2-6). Most of such studies were conducted in
patients with AMI and the majority was from patients
with ST-segment elevation myocardial infarction.
Information from the present study is unique in that it
was obtained specifically from patients with NSTEACS,
which includes both underlying pathology of
myocardial infarction (represented by patients with
NSTEMI) and myocardial ischemia (represented by
patients with UA). The results showed that LV systolic
dysfunction and the more advanced LV diastolic
dysfunction were more prevalent in patients with
NSTEMI than in those with UA, which may reflect the
severity of underlying acute coronary pathology and
extent of myocardial injury.
Diastolic dysfunction occurs early after
acute coronary artery occlusion with or without LV
systolic dysfunction. Several diastolic parameters
assessed by transthoracic echocardiography have also
been shown to be strong prognostic indicators after
AMI(7-12). LV diastolic dysfunction contributes to signs
and symptoms of heart failure and mortality after AMI,
regardless of LV systolic function. Data from
previous studies showed that the more severe the
diastolic dysfunction the worse the prognosis after
AMI(7,8,12-14). Therefore, an appropriate treatment to
lessen the severity of diastolic dysfunction should
improve the clinical outcomes after AMI. E/E’ ratio,
Doppler-derived deceleration time and LAV have
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reflected the severity of diastolic function. E/E’ has
been shown to be the most accurate non-invasive
predictor of elevated LV filling pressure and pulmonary
capillary wedge pressure (15) and high E/E’ was
associated with adverse outcomes and worse survival
after AMI(7-9). Short deceleration time has also been
reported to be an important prognostic value after AMI
and correlated with the well-documented prognostic
value of clinical indicators of LV filling pressures, such
as Killip class(9,12,16,17). Previous study has found that
myocardial ischemia resulted in significant LA dilation,
depressed LA systolic function, and altered LA
diastolic stiffness(18). LAV has been described as an
important predictor of survival after acute AMI(11,19).
The present study showed that among patients with
NSTEACS, the more severe-group, patients with
NSTEMI, presented more frequently with the more
advanced LV diastolic dysfunction as described by
shorter deceleration time, higher E/E’ ratio and larger
LAV. The study was exclusively conducted in patients
with NSTEACS to echocardiographically differentiate
those with NSTEMI and UA. These findings may have
prognostic and therapeutic implications among the
subgroup of patients with NSTEACS.
Study Limitations
The echocardiography was performed mostly
in the intensive care unit and the in-patient medicine
wards, not in the standard echocardiography laboratory
and some of them were performed during out-of-office
hours. Therefore, data regarding the inter-observer
variability were not available.
Conclusion
Data from the present study demonstrate that,
among patients with NSTEACS, LV systolic and
diastolic dysfunction was more frequent and more
severe in patients with NSTEMI that in those with UA.
This may therefore assist in the risk stratification and
clinical decision-making of patients with NSTEACS.
Potential conflicts of interest
None.
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ผูป้ ว่ ยกล้ามเนือ้ หัวใจตายเฉียบพลันชนิด ST ไม่ยก มีความผิดปกติในการบีบตัวและคลายตัวของ
กล้ามเนือ้ หัวใจแบบรุนแรงกว่าผูป้ ว่ ยกล้ามเนือ้ หัวใจขาดเลือดแบบ unstable angina
นิธมิ า เชาวลิต, ฤดีกร เอือ้ เศรษฐศักดิ,์ ยิง่ ศักดิ์ สันธนาฃร, เดโช จักราพานิชกุล, เมทินี กิตติโพวานนท์, ศรีสกุล
จิรกาญจนากร
ภูมหิ ลัง: ผูป้ ว่ ยกล้ามเนือ้ หัวใจขาดเลือดเฉียบพลันชนิด ST ไม่ยก (NSTEACS) มีความหลากหลายในหลายด้านได้แก่
อาการทางคลินิก คลื่นไฟฟ้าหัวใจ ค่าเอนไซม์กล้ามเนื้อหัวใจ ผลการตรวจคลื่นเสียงสะท้อน หัวใจและการฉีดสี
หลอดเลือดหัวใจ จุดประสงค์ของการศึกษานี้เพื่อหาความแตกต่างของตัวแปรที่บ่งชี้การ บีบตัวและคลายตัว
ของกล้ามเนื้อหัวใจในผู้ป่วยกลุ่มย่อยของผู้ป่วย NSTEACS
วัสดุและวิธกี าร: ผูป้ ว่ ย NSTEACS จำนวน 121 คน (อายุเฉลีย่ 68.6 ปี เพศชายร้อยละ 45) ได้รบั การตรวจคลืน่ เสียง
สะท้อนหัวใจภายใน 48 ชั่วโมง ที่รับเข้านอนในโรงพยาบาลศิริราช
ผลการศึกษา: มีผู้ป่วยโรคกล้ามเนื้อหัวใจตายเฉียบพลันชนิด ST ไม่ยก (NSTEMI) ร้อยละ 59 และผู้ป่วย
โรคกล้ามเนื้อหัวใจขาดเลือดแบบ unstable angina (UA) ร้อยละ 41 และไม่พบความ แตกต่างของข้อมูลพื้นฐาน
ทางคลินิกระหว่าง 2 กลุ่ม ผู้ป่วยกลุ่ม NSTEMI มีความผิดปกติของ กล้ามเนื้อหัวใจบางตำแหน่ง และการบีบตัว
ของหัวใจลดลงกว่าปกติมากกว่าในผู้ป่วยกลุ่ม UA ผู้ป่วยกลุ่ม NSTEMI พบความผิดปกติในการคลายตัวของหัวใจ
ได้บ่อย และรุนแรงกว่าผู้ป่วยกลุ่ม UA
สรุป: ผู้ป่วยกลุ่ม NSTEMI พบความผิดปกติในการบีบตัวและคลายตัวของหัวใจได้บอ่ ย และรุนแรงกว่าในผูป้ ว่ ยกลุม่
UA ข้อมูลนี้อาจเป็นประโยชน์ในการประเมินความเสี่ยงและการพยากรณ์โรคในผู้ป่วยกลุ่ม NSTEACS ได้
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