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Journal of Korean Academy of Nursing (2002) Vol. 32, No. 7
Anxiety after Acute Myocardial Infarction
and In-Hospital Complications
Kyungeh An, PhD, RN
Purpose of the study. A retrospective and descriptive survey was conducted to investigate the level of anxiety
that patients experience in early stage of AMI and to examine whether anxiety independently predict inhospital complications.
Significance of the study. AMI is a major cause of death and disability. Anxiety may contribute to developing
complications and mortality. However, the association between anxiety and complications has not been
examined.
Results. Data were analyzed for 424 AMI patients enrolled for MICA (Myocardial Infarotion Complication and
Anxiety) project. The mean score of the state anxiety inventory (SAI) measured within 72 hours after
admission for the whole sample was 39.14 (±12.77) and ranged from 18 to 80. Overall, 161 patients
(38.0%) experienced at least one episode of in-hospital complication (i.e. VT, VF, reinfarction, recurrent
ischemia or cardiac death). Incidence of in-hospital complications was higher in the high anxiety group than
in the low anxiety group (45.4% vs. 31.2%). There were significant differences in the incidence of recurrent
ischemia between groups with low level of anxiety and high level of anxiety (27.5% vs. 18.9%). According
to the Ward criterion from the logistic regression, anxiety reliably predicted the occurrence of in-hospital
complications. Anxiety (odds ratio = 1.75, 95% CI 1.01-3.01, p= 0.04) significantly contributed to the
model. Patients who were in the high anxiety group were 1.8 times more likely to have in-hospital complications than those who were in the low anxiety group.
Conclusion and suggestions. This finding confirms that patients experience significant level of anxiety early
after AMI, and this anxiety, after controlling other risk factors for the complications, is a reliable predictor
of in-hospital complications.
Key Words: anxiety, acute myocardial infarction, in-hospital complications
INTRODUCTION
Acute myocardial infarction (AMI) is defined as irreversible necrosis of myocardial tissue caused by inadequate blood flow to the myocardium for a critical period
of time (Vincent, 1994). Patients who experience AMI
inevitably experience anxiety. Anxiety is defined as a
feeling of fear, tension, panic or the expectancy that
something unpleasant is going to happen and is almost
invariably accompanied by physical signs and symptoms
(Medalie & Goldbourt, 1976). Anxiety develops early
after AMI, continues into the recovery phase and influences the prognosis of the disease (Malan, 1992; Stern,
1984).
Although anxiety is expected to some degrees in all
AMI patients (Stern, 1987), it can be debilitating to
many patients (Krantz, 1980). If severe and untreated,
1. Ewha Womans University, College of Nursing Science
Corresponding author: Kyungeh An, PhD, RN, Ewha Woman’
s University, College of Nursing Science
11-1 Daehyun-dong, Seodaemun-gu, Seoul 120-750, Korea
Tel: 82-2-3277-3926 Fax: 82-2-3277-2850
Received August 6, 2002 ; Accepted December 5, 2002Januar 31, 2000
1000 Journal of Korean Academy of Nursing Vol. 32, No. 7
anxiety may contribute to fatal cardiac events by exaggerating sympathetic activity (Krantz, Helmers, Nebel,
Gottniener, & Rosanski, 1990; Larson, Schneiderman, &
Pasin, 1986; Lown & Desilva, 1978; Lown et al., 1980).
Exaggerated sympathetic activity increases circulating
catecholamines and results in cardiovascular over-reactivity. Cardiovascular reactivity often results in tachycardia and increases systemic vascular resistance.
Sympathetic hyperactivity also increases the risk of ventricular arrhythmias, cause myocardial ischemia by increasing oxygen consumption, and increase left ventricular afterload by producing systemic vasoconstriction
(Swan, 1991). A previous study found that anxiety early
after AMI independently predicted in-hospital complications such as ischemic and arrhythmic events (Moser &
Dracup, 1996).
In the clinical setting, however, both assessment and
treatment of anxiety tend to be undervalued. This is partially because the physical symptoms of anxiety are often masked by the symptoms of cardiac disease such as
chest pain, shortness of breath, rapid pulse, elevated
blood pressure, and palpitations. In addition, lack of
health care providers’ awareness of the physiologic consequences of anxiety may contribute to its under-treatment.
The vast majority of investigators who conducted anxiety research with AMI patients focused on the anxiety
after discharge from the hospital. Only a limited number
of investigators paid attention to the anxiety early after
AMI and its potential physiological effects on the development of in-hospital complications (Boogaard, 1984;
Moser & Dracup, 1996; Hillers, 1994; Stern, 1976).
Increasing evidence suggests that anxiety early after
AMI plays a significant adverse role in AMI recovery
(Bloch & Maeder, 1975; Booth-Kewley, & Friedman,
1987; Brown & Mumford, 1984; Byrne & Whyte, 1983;
Hacket & Cassem, 1984; Moser & Dracup, 1996).
Moreover, most investigators of these studies measured
anxiety several days and weeks after AMI, and missed
the peak level of anxiety early after AMI (Boogaard,
1984; Hillers, 1994; Stern, 1976). Assessing anxiety in
early stages of AMI that includes the time of peak anxiety is critical for understanding the significance of anxiety. Furthermore, examining the relationship between
anxiety and in-hospital complications is also important
to prevent in-hospital complications and early mortality
from AMI. There is lacking of data based on clinical research that supports the negative effects of anxiety on
prognosis of AMI. Therefore, research studies that investigate anxiety early after AMI and examine the effects of
anxiety on development of in-hospital complications are
needed.
The purposes of this study were to investigate the level
of anxiety that patients experience in early stage of
AMI, and to examine whether anxiety independently
predict in-hospital complications. Findings from this
study will call more attention of clinicians to the importance of assessing and treating patients’ anxiety during
the early stage of AMI.
Specific aims of this study were as follows:
(1) Describe the anxiety level patients experienced
during 72 hours of their arrival at the hospital.
(2) Compare in-hospital complications between two
groups experienced low vs. high level of anxiety.
(3) Test the significance of anxiety after controlling traditionally known risk factors that predict in-hospital
complications.
METHODS
1. Research Design
A retrospective and descriptive survey was conducted.
2. Subjects
Patients who were admitted to coronary care units
and met the following criteria were eligible for the
study: (1) diagnosis of AMI confirmed by elevated cardiac enzymes (i.e. CK and CK-MB, or troponin) and
typical EKG changes; (2) free of cognitive impairment
that might interfere with ability to participate in a 15-20
minute interview (3) free of non-cardiac serious or life
threatening comorbidities such as sepsis, stroke, or
acute renal failure. Patients were excluded if they suffered a peri-procedural MI because they might experience psychological distress in a different pattern. For
patients who were waiting for major diagnostic or treatment procedures such as cardiac catheterization, the interview was postponed because the anxiety caused by
impending procedures could confound the anxiety following AMI.
Four hundred twenty four AMI patients were enrolled
in this study, including 281 men and 143 women. A
sample size of 400 was originally planned based on the
following information: (1) medium effect size for the association between anxiety and in-hospital complications;
(2) α=0.05; and (3) power=0.80; (4) expected in-hospital
An Anxiety and MI Complications 1001
complication rate of 25% (Moser & Dracup, 1996).
Data were colleded from September 1996 to September
1999.
ranged from .86 to .95 by means of Kuder-Richardson
20 formula. The Chronbach’s α· was 0.94 in this sample.
5. Data Analysis
3. Procedures
Structured interview was conducted to obtain data in
coronary care units of five large urban university medical centers and two large private hospitals in the United
States and one private hospital in Australia. Data were
consisted of socio-demographic data, clinical information, and anxiety assessment. Socio-demographic data
included gender, age, marital status, work status, yearly
income, and education level.
Clinical data were obtained from the medical record
review. Clinical data included the presence of comorbidities, information about diagnostic procedures and about
the major medical and surgical treatment that the patient
received during the hospitalization. Comorbidities included history of hypertension, diabetes, previous myocardial infarction, angina; and coronary artery disease
without prior coronary events. Diagnostic procedures included cardiac catheterization and/or echocardiogram,
insertion of Swan Ganz catheter or central venous pressure line or arterial pressure line. Therapeutic procedures include major medical and surgical treatments.
Medical treatment refers to medication for the treatment
of AMI such as primary thrombolytic therapy, use of βblockers and supportive medication for pain and anxiety
use of ventilator, and insertion of intra-aortic balloon
pump, cardioversion and defibrillation. Surgical treatments include insertion of temporary pacemaker, percutaneous transmural coronary angiography with or without stent, and coronary artery bypass grafting (CABG)
surgery.
4. Instrument
State anxiety was measured by the state anxiety inventory (SAI) subscale of the State-Trait Anxiety
Inventory (STAI) (Speilberger, 1983). The SAI is a widely used and well established instrument for both psychiatric patients and medically ill patients.
The SAI consists of 20 statements that are rated by patients on a 4-point rating scale. Responses range from
“not at all (1)” to “very much so (4)” as patients rate
how they feel at the current time. Item scores are summarized, scores on the instrument range from 20 to 80,
and higher scores indicate higher levels of anxiety.
Webb and Riggin (1994) reported that reliability
Data were analyzed using SPSS 9.0-PC. To describe
the level of anxiety that patients experienced in early
stage of AMI, descriptive statistics were used.
Independent t-test was conducted to compare the incidence of in-hospital complications between the groups
with low and high level of anxiety. A multiple logistic regression was conducted to examine whether anxiety early after AMI can predict in-hospital complications after
controlling other physiologic risk factors.
RESULTS
1. Socio-demographic and clinical data
Data were analyzed for 424 subjects who included 281
(66.3%) men and 143 (33.7%) women. The sociodemographic characteristics of the entire sample are summarized in Table 1. The mean age of the sample was 62(±
13) years and ranged from 24 to 92 years. The mean
years of education was 13 (±3). Approximately 68.2%
of the sample were married, and 38% had less than
$20,000 annual income.
Clinical characteristics of the sample are summarized
in Table 2. Clinical characteristics included Killip classification at the time of admission, type and location of infarction, systolic and diastolic blood pressure and pulse
rate at the time of admission, peak level of cardiac enzymes, peak level of chest pain reported by patients,
and left ventricular ejection fraction.
Table 1. Sociodemographic Characteristics of Sample
Sociodemographic Characteristics
N (%)
Marital Status
Married
Single*
Widowed
289 (68.2)
074 (17.5)
061 (14.4)
Yearly Income
<$5,000
$5,000-$20,000
$20,000-$40,000
$40,000-$60,000
>$60,000
17 (4.5)
124 (33.2)
114 (30.5)
069 (18.4)
050 (13.4)
Characteristics (Valid N)
Mean±SD
Age in years (426)
Education in years (415)
62±13
13±30
*Single represented single, divorced, separated, and cohabitant
1002 Journal of Korean Academy of Nursing Vol. 32, No. 7
Most of subjects (93.3%) were in either Killip Class I
or II with 258 (60.8%) fulfilling criteria for Killip Class
I, indicating no signs or symptoms of left ventricular dysfunction, and 137 (32.5%) fulfilling criteria for Class II,
indicating mild to moderate failure. Only 27 subjects
(6.4%) fulfilled criteria for class III indicating pulmonary
edema. One subject was admitted (.2%) in class IV indicating cardiogenic shock.
Regarding type of AMI, 251 (60.9%) subjects had Qwave infarction and 161 (39.1%) had non Q-wave infarction. The two most frequent locations of infarction
were inferior (51.6%) and anterior (41.5%). Mean
blood pressure of the sample was 142±29/81±19 and
the pulse rate was 79±20. The mean score of the
subjects for perceived level of chest pain reported by patients using a 0 to 10 scale (0 means no pain, 10 means
the worst pain ever experienced) was 6.91±2.54.
Data about the comorbidities of diabetes, hypertension, history of smoking, previous infarction, angina, and
other coronary artery disease in men and women are
summarized in Table 3. Hypertension was present in 248
(58.8%) subjects and diabetes was present in 93
(22.0%) subjects. In this sample, 35.6% of the subjects
were current smokers at the time of infarction. Twenty
eight percent of subjects experienced previous AMI and
2. Level of anxiety patients experienced during 72
hours of their arrival at the hospital
Table 2. Clinical characteristics of the sample
Clinical Characteristics (Valid N)
N (%)
Killip Classification (N=421)
Killip class I
Killip class II
Killip class III
Killip class IV
Type of MI (N=412)
Q-wave
Non Q-wave
251 (60.9)
161 (39.1)
Location of MI by EKG (N=376)
Anterior Infarction
Inferior infarction
Posterior infarction
Lateral infarction
156 (41.5)
195 (51.9)
057 (15.2)
077 (20.5)
Apical infarction
Systolic blood pressure (mmHg)
Diastolic blood pressure (mmHg)
Pulse rate (beat/mm)
Peak CPK (U/L)
Peak CKMB (ng/ml)
Peak Troponin (ng/ml)
Peak chest pain (0-10)
LVEF (%)
37% of the subjects experienced previous angina.
Previously known coronary artery disease without a cardiac event was identified in approximately 19% of the
subjects.
In this sample, 32.6% of AMI patients had thrombolytic therapy in the emergency department. Among
these, 28.5% received t-PA (tissue plasminogen activator) and 4.8% received Streptokinase. Nitrates were the
most frequently given medication to the subjects in the
emergency department (89%). Heparin was given to
85.9% of the sample and acetyl salicylic acid (ASA) was
given to 81.9% of the sample. Beta-blockers were given
to 53% of the sample. Anxiolytics were given to 32.1%
of the subjects. Twenty four percent of the subjects had
primary percutaneous transluminal coronary angioplasty
(PTCA) as an initial treatment.
Data related to the treatment and procedures in the
CCU are summarized as following. Beta-blockers, lidocaine either for prophylactic purpose or in response to
arrhythmias, calcium channel blockers, digitalis, inotropes, heparin, ace-inhibitors, and nitrates were used.
Overall, 349 (83.3%) patients had cardiac catheterization. Among these, 266 (63.5%) patients had PTCA and
217 (52.0%) received a stent.
256 (60.8)
137 (32.5)
27 (6.4)
01 (0.2)
12 (3.2)
Mean±SD
142±29
081±19
079±20
1281.92±1391.67
140.44±156.64
063.58±193.86
6.91±2.54
51.16±12.22
The mean score of the SAI for the whole sample was
39.14±12.77 and ranged from 18 to 80. Women reported higher level of anxiety than men (42.03±12.86 vs.
37.74±12.51) (t=-3.30, df=421, p<0.001).
Age had a significant effect on the anxiety score: F (2,
481) = 5.258, p= 0.022. Marital status: F (2,
421)=3.774, p=0.024; use of ASA in the emergency department: F(1, 418) = 9.147, p= 0.003; use of anxiolytics in the emergency department: F (1, 413)=22.418,
p<0.001; and use of IV nitrate in the CCU : F(1, 409)=
Table 3. Comorbidities and History of Heart Disease
Comorbidity & History of Heart Disease (Valid N)
Hypertension (422)
Diabetes Mellitus (N=423)
Smoking (N=424)
Previous MI (N=424)
Previous angina (N=418)
Previous CABG (N=424)
PTCA (N=424)
Previous Stent (N=424)
History of known CAD without events (N=423)
N (%)
248 (58.8)
093 (22.0)
151 (35.6)
120 (28.3)
153 (36.6)
40 (9.4)
076 (17.9)
33 (7.8)
082 (19.4)
An Anxiety and MI Complications 1003
4.428, p= 0.036 had main effects on the anxiety score
tested by the multifactorial ANOVA. Patients in the single group, in which unmarried single, divorced, separated, and cohabitation were included, had higher anxiety
than the married group or the widowed group (43.32±
13.20 vs. 38.51±12.73 and 37.36 ±11.47, respectively). Patients who received ASA in the emergency department had higher anxiety than those who did not (39.85
±12.80 vs. 35.96±11.47). Patients who received anxiolytics in the emergency department had higher anxiety
than who did not (42.82±12.01 vs. 37.59±12.90).
Patients who received IV nitrate in the CCU had lower
anxiety than those who did not (38.30±12.88 vs. 40.82
±12.34).
3. Compare in-hospital complications between low vs.
high anxiety groups
Overall, 161 patients (38.0%) experienced at least one
episode of in-hospital complication (i.e. ventricular
tachycardia, ventricular fibrillation, reinfarction, recurrent ischemia or cardiac death). The percentage of patients who experienced any individual complication was
less than 10% with the exceptions of sustained ventricular tachycardia (15.2%) and recurrent ischemia (23.3%).
Ventricular fibrillation occurred in 21 subjects (5%), recurrent infarctions occurred in 9 subjects (2.1%) and
cardiac death occurred in 5 subjects (1.2%) of the sample.
Based on a median split, subjects’ SAI scores were divided into the following two groups: 1) above the median, and 2) below the median. The incidence of complications between the two groups was compared using Chisquare analyses. Comparison of the in-hospital compli-
cations between the high and low anxiety groups measured by the SAI is shown in table 4. There were significant differences in the incidence of recurrent ischemia
group compared to the low anxiety group experienced
recurrent ischemia (27.5% vs. 18.9%). Overall, incidence of in-hospital complications was higher in the high
anxiety group than in the low anxiety group (45.4% vs.
31.2%).
4. Effect of anxiety: testing significance of anxiety in
predicting in-hospital complications.
To identify potential risk factors including anxiety that
predict in-hospital complications, univariate analyses
were first performed. Sociodemographic and clinical
characteristics that were significantly different between
the complication and non-complication groups were
identified using Chi-square tests for nominal and ordinal
variables and independent t-tests for interval level variables (Table 5). Among sociodemographic variables,
marital status was associated with the presence of overall
complications. More subjects in the married group developed complications than in the single or widowed
groups (74.5%, 16.1%, and 9.3%, respectively): x2 (2,
N=424) = 6.437, p= 0.040. Patients who had diabetes
experienced complications less often than those who did
not have diabetes (16.3% vs. 83.8%); x2 (1, N=423) =
4.936, p=0.017.
Among clinical characteristics, peak level of creatine
kinase isoenzymes (CKMB) and left ventricular ejection
fraction (LVEF) differentiated the complication and noncomplication groups. The mean value of peak CKMB
was higher in the group with complications than in the
non-complication group (173.93±193.00 ng/ml vs.
Table 4. Complications by High and Low Anxiety Measured by the SAI
Low Anxiety*
n (%)
High Anxiety*
n (%)
x2
p
27 (12.5)
7 (3.2)
37 (18.2)
6 (3.0)
2.657
3.556
0.068
0.169
9 (4.2)
1 (0.5)
12 (5.9)0
1 (0.5)
0.670
0.716
0.276
0.699
41 (18.9)
14 (6.5)0
3 (1.4)
1 (0.5)
68 (31.2)
56 (27.5)
23 (11.3)
6 (3.0)
4 (2.0)
93 (45.4)
4.350
4.834
1.241
2.143
9.029
0.024
0.089
0.222
0.167
0.002
VT
any episode
multiple episodes
VF
any episode
multiple episodes
Recurrent Ischemia
any episode
multiple episodes
Re-infarction
Cardiac death
Any complication
*groups formed using a split at the median of 37 of state anxiety
1004 Journal of Korean Academy of Nursing Vol. 32, No. 7
120.65±126.37 ng/ml): t (402)= -3.351, p= 0.001. The
patients who had higher CKMB more often experienced
complications than patients who had lower CKMB
(56.6% vs. 43.4%).
Left ventricular ejection fraction was lower in the complication group than in the non-complication group
(49.26±12.25% vs. 52.39±12.01 %): t (290)=2.270,
p=0.031. The patients who had lower LVEF more often
experienced in-hospital complications than patient who
had higher LVEF (81.0% vs. 19.0%).
A logistic regression analysis was performed with the
incidence of overall in-hospital complications as the outcome variable. Predictors identified from the univariate
analyses were marital status, history of diabetes, CKMB
and LVEF, and anxiety. In addition, age was included,
despite its lack of association with complications on the
univariate analysis in this sample, because of its potential clinical importance. Age was a predictor of in-hospital complications in a recent study (Moser & Dracup,
1996). Marital status, comorbidity with diabetes, level of
CKMB, LVEF and age were first forced into the logistic
regression model. Anxiety was then forced into the
model. Table 6 shows the regression coefficients, Wald
statistics, odds ratio and 95% confidential intervals for
odds ratios for each of the seven predictors.
A test of the reduced model with five predictors
against a constant model was statistically significant indicating that the predictors, as a set, reliably distinguished
between the complication group and the non-complication group: x2 (6, N=323)= 17.486, p=.0077. Prediction
success was low for the complication group (13.28%)
and high for the non-complication group with 92.31%
correctly predicted. Successful prediction rate was acceptable at 60.99%.
Introduction of anxiety to the regression model significantly improved the model in terms of the Goodness of
Fit (321 vs. 324) and increment of Nagelkerke R2 (0.071
vs. 0.137): x 2 (2, N=323) = 16.99 , p=1003.002.
According to the Ward criterion, anxiety measured by
the SAI reliably predicted the occurrence of in-hospital
Table 5. Sociodemographic and clinical factors that discriminate in-hospital complications
Variables
Marital status
Married
Single
Widowed
Diabetes
Yes
No
CKMB*
Below
Above
LVEF**
Below
Above
Had any complications
N (%)
x2
df
p
120 (74.5)
026 (16.1)
15 (9.3)
6.437
2
0.040
026 (16.3)
134 (83.8)
4.936
1
0.017
066 (43.4)
086 (56.6)
3.603
1
0.036
026 (19.0)
111 (81.0)
4.550
1
0.025
*CKMB = Creatine kinase isoenzyme MB: below = below median; above = above median
**LVEF = left ventricular ejection fraction; below = below median; above = above median
Table 6. Regression on In-Hospital Complications as Outcome and Seven Predictors
Variable
MARITAL STATUS
DIABETES
CKMB
LVEF
AGE
SAI
(CONSTANT)
B
Ward F
Significance
Odds ratio
0.2552
0.7055
-0.3317
1.0258
0.2501
0.5586
-0.2687
0.3869
5.4152
1.8775
8.5997
0.8761
4.0074
0.6574
0.5339
0.0200
0.1706
0.0034
0.3493
0.0435
0.4175
1.2907
2.0249
0.7177
2.7892
1.2841
1.7483
95% Confidence Interval for Odds Ratio
Lower
Upper
0.5776
1.1177
0.4465
1.4052
0.7607
1.0165
2.8847
3.6684
1.1535
5.5362
2.1678
3.0067
Legend CI= Confidence Interval (95%); SE= Standard Error *Model Chi-Square=33.465, df=6, p=.000
An Anxiety and MI Complications 1005
complications. Anxiety measured by the SAI (odds ratio
= 1.75, 95% CI 1.01-3.01, p= 0.04) significantly contributed to the model. Patients who were in the high
anxiety group were 1.8 times more likely to have in-hospital complications than those who were in the low anxiety group. This finding confirms that anxiety after AMI,
after controlling other risk factors for the complications,
is a reliable predictor of in-hospital complications.
DISCUSSION
Although any precise statistics are not available, significant number of death from AMI is consisted of in-hospital mortality. In-hospital mortality may be associated
with the development of in-hospital complications.
Development of complications is largely responsible for
the 10-15% mortality rate in the early stage of AMI
(Shah et al., 1994; Swan, 1991). Left ventricular dysfunction (Hendel, 1990), atrial fibrillation (Henning,
1975; Kannel & Abbott, 1987), supraventricular tachycardia (Henning, 1975), left bundle branch block
(Henning, 1975), atrioventricular block (Tofler et al.,
1987), recurrent ischemia, and reinfarction are common
complications associated with in-hospital death.
Anxiety is an important phenomenon in AMI patients
because it may cause negative physiologic effects during
recovery (Krantz, Helmers, Nebel, Gottniener, &
Rosanski, 1990; Larson, Schneiderman, & Pasin, 1986;
Lown & Desilva, 1978; Lown et al., 1980). Anxiety may
contribute to in-hospital complications after AMI by exaggerating SNS activation. An activated SNS stimulates
the release of catecholamines. Excessive catecholamines
can induce hyperreactivity of the cardiovascular system
(Bigger et al, 1992; Lown, DeSilva, Reich & Murawski,
1980; Vincent, 1994). Specifically, SNS arousal may increase coronary artery basal vascular tone (Panza,
Epstein, & Quyyumi, 1991), increase platelet aggregation (Priori, Zuanetti, & Schwartz, 1988), increase intraluminal shearing forces, myocardial oxygen consumption, and decrease the fibrillation threshold (Karmarck &
Jennings, 1991). Subsequently, SNS activation may exacerbate ischemia, contribute to the development of
ventricular arrhythmias, and result in infarction and cardiac death (Karmarck & Jennings, 1991). These cardiac
events can occur in the early stage of AMI, and are defined as in-hospital complications in this study. These
complications are subsequently associated with in-hospital and one year mortality (Dittrich, Gilpin, & Nicod,
1988; Greenland, Riecher-Reiss, Goldbourt, Behar, &
the Israeli SPRINT Investigators, 1991; Kannel, Sorlie, &
McNamara, 1979; Maynard et al., 1997; Tofler et al.,
1987).
Overall findings of the sociodemographic and clinical
characteristics of the sample in this study demonstrate
that this sample was similar to that of other published
studies (Dittrich, Gilpin, Nicod, 1988; Greenland, 1991;
Hamilton & Seidman, 1993; Hendel, 1990; Kannel &
Abbott, 1987; Maynard, 1991; Moser & Dracup, 1996).
Thus we can conclude that no obvious bias was introduced in our sampling.
The overall mean score of anxiety measured by the
SAI was 39±13, and ranged from 18 to 80 in this study.
Age specific normative values for persons aged 50 to 69
were 34.51±10.34 for men and 32.20±8.67 for women
(Spielberger, 1983). The mean score of state anxiety of
general medical surgical patients has been reported as
42.38 ±13.79. Therefore the overall mean score of anxiety on the SAI scale in this sample was higher than the
normative value of the same age group, yet lower than
the mean score of the general medical surgical patients.
Comparisons of anxiety scores to previous studies are
summarized in Table 7. Studies in which state anxiety
had been measured during the stay in the CCU were selected for these comparisons. State anxiety scores were
abstracted from either descriptive studies or the baseline
anxiety of the intervention studies. However direct comparisons among studies may not appropriate because
level of anxiety was measured in different time across
studies.
The presence of gender differences in anxiety and in
the association between anxiety and in-hospital complications have been controversial. In this study, the mean
score of anxiety was higher in women than in men
(42.03±12.86 vs. 37.74±12.51). This gender differences in anxiety may support the previous investigators
assumption that anxiety, in addition to the physiologic
factors, may play an important role in gender difference
in recovery and prognosis after AMI. Women show higher in-hospital and one year mortality and poorer health
outcomes after AMI (Adams, Jemieson, Rawles, Trent,
& Jennings, 1995; AHA, 1998; Greenland, ReicherReiss, Goldbourt, & Behar, 1991; Kannel & Abbott,
1987; Lerner & Kennel, 1986; Murabito, 1993; Tofler,
Stone, 1987;Weaver, White, Wilcox, 1996). The older
age of women when they experience an AMI partially
explains their higher mortality. Anatomical and physio-
1006 Journal of Korean Academy of Nursing Vol. 32, No. 7
Table 7. Comparison of Anxiety Scores on SAI in Current Studies
Author (Year)
When anxiety was measured
Anxiety scores
Glick (1986)
Cristies (1988)
Zimmerman (1988)
White (1992)
Web & Riggin (1994)
Rose et al. (1994)
Elliott (1994)
Hillers et al.(1994)
Crowe (1996)
Frasure-Smith et al. (1997)
Present study (1999)
within 3 hours after transferred from CCU
4 days after admission
in CCU
72 hours of admission
24-48 hours prior to discharge from the hospital
24 hours after transferred from CCU
in CCU
before discharge
1-3 days after admission
in CCU
72 hours after admission
35.37**
42.5±1.4
35.7±9.2
47.78±5.37*
M:36.4/W:35.8**
39.2±10.8
38.6**
47.8±9
M43±10/W 43±11
45.70±497.40
39.14±12.77
*Only patients with STAI>40 were included; **SD not reported
M= men; W= women
logic differences in the cardiovascular system between
men and women may also explain gender differences in
the prognosis after AMI (Adams et al., 1995; Wingate,
1997).
Numerous risk factors contribute to the development
of complications and to subsequent mortality. Among
socio-demographic variables, marital status was a significant discriminator of in-hospital complications. In addition, history of diabetes was also a significant predictor
of in-hospital complication. Among the clinical variables
CKMB and LVEF were significantly differentiate prevalence of in-hospital complications. In addition to these
socio-demographic and clinical variables, anxiety was
shown to play an important role in developing in-hospital complications. The group with higher anxiety had
more in-hospital complications than did the group with
lower anxiety. In addition, anxiety after controlling socio-demographic and clinical factors, independently predict in-hospital complications.
Findings of a significant contribution of anxiety to the
prediction of in-hospital complications are of interest because they demonstrate a directional relationship. In this
study, cardiac events that occurred only after anxiety
was measured were included as dependent variables. By
controlling the time of anxiety and in-hospital complications measurement, greater strength was given to the assertion of association between anxiety and complications as directional. This method was chosen to improve
the lack of directional relationship in previous studies. It
was unclear in previous studies whether anxiety influenced the health outcomes or whether the poor health
outcomes caused anxiety. Although any causal relationship cannot be addressed in this study, a directional relationship was addressed by controlling the time of mea-
suring dependent and independent variables.
Additionally, the findings of the logistic regression provided the likelihood of each predictor of development of
in-hospital complications. Patients with low LVEF are
approximately three times as likely to have complications compared to patients with high LVEF. Patients with
diabetes were less likely to have complications. Patients
with high anxiety are twice as likely to have complications. The significant contribution of anxiety to the prediction of in-hospital complication supported the proposed theoretical framework. Findings regarding contribution of each predictor were consistent with findings
from previous studies with an exception of the contradictory role of the presence of diabetes. In most studies,
patients with diabetes experienced more complications.
In this study, however, patients with diabetes were less
likely to experience complications. The lower incidence
of complications in patients with diabetes might be due
to the aggressive treatment along with health care
providers’ appreciation of the negative effects of diabetes
on the prognosis following AMI.
CONCLUSION
Findings from this study suggest important clinical implications. The overall high level of anxiety provides a
rationale for health care providers to assess and treat patients’ anxiety as soon as possible. Although the exact
time for the peak level of anxiety is not known, anxiety
consistently is highest during the earliest measurements.
This implies that the true peak level of anxiety may have
been missed in many studies.
Findings of a significant gender difference in anxiety
suggest that women in particular should be assessed for
An Anxiety and MI Complications 1007
anxiety during the early stage of AMI. Some investigators pointed out the underuse of anxiolytics for AMI patients. This study also revealed underuse of anxiolytic
for women in emergency department. Considering its
potential effects on the prognosis of AMI, anxiety
should be treated as well as other physical symptoms
early after AMI.
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