Variability, prediction and prognostic significance of chest pain in acute myocardial infarction

The relationship between chest pain duration and the incidence of acute myocardial infarction among patients with acute chest pain

OBJECTIVE

Eight to ten million individuals are evaluated for chest pain (CP) in Emergency Departments (ED) in the United States each year. CP characteristics are an important factor used to help determine a diagnosis. We studied the relationship between the duration of CP and the diagnosis of acute myocardial infarction (AMI) in patients evaluated in the ED.

METHODS

The study population consisted of a sub-group analysis of a previously published study. The survey population consisted of 1024 consecutive encounters of patients who were evaluated for possible ACS in the ED of Henry Ford Hospital between January and May of 1999, CP duration could be obtained in 426 who were included in this analysis.

RESULTS

Of the 426 patients included in the study, 38 (8.9%) had a final diagnosis of AMI, with a median CP duration of 120 minutes (interquartile range, 30-240 minutes), compared with 40 minutes (interquartile range, 6-180 minutes) in patients without AMI (p =0.003). In patients with CP duration less than 5 minutes, there were no AMIs and no deaths at 30 days. There were 10 patients dead at 30 days, with a median CP duration of 180 minutes (interquartile range, 120-1440 minutes) compared to 40 minutes (interquartile range, 10-180 minutes) in patients alive at 30 days (p = 0.011). A longer CP duration and ST depression of 1 mm of less were independently associated with a final diagnosis of AMI.

CONCLUSION

Patients with AMI have longer duration of CP than those without AMI; patients with CP of short duration, less than 5 minutes, are unlikely to have AMI and have a good prognosis at 30 days.

Extracardiac contributions to chest pain perception in patients 6 months after acute myocardial infarction

OBJECTIVES

The amount of perceived anginal pain in patients after infarction deserves the attention of the physician. This study sought to identify the modulating influence of extracardiac factors on persistent angina pectoris after myocardial infarction.

METHODS AND RESULTS

A total of 552 male survivors of acute myocardial infarction (age 29 to 65 years, median 54 years) were followed for a period of 6 months; the affective state was assessed immediately after the acute event. The prognostic importance of postinfarction depression on chest pain perception was evaluated 6 months after the cardiac event in 376 patients. After the 6-month follow-up period, 199 (53%) of the patients with myocardial infarction had angina pectoris. Somatic risk factors and electrocardiographic data at initial testing did not contribute to the risk of having chest pain. However, patients with high levels of depression at initial testing had an almost 3-fold risk of having angina pectoris 6 months after the index event. Older age, lower social class status, and preinfarction angina were also significantly related to angina pectoris at the end of the study. Patients who were pain free before the index infarction reported significantly more symptoms of chest pain at the study end point (P </=.02), when they had moderate to high degrees of postinfarction depression. In the logistic regression model, depression, then followed by preinfarction angina pectoris and low social class index, contributed significantly to the prediction of follow-up angina pectoris.

CONCLUSIONS

The results of this study add evidence to the hypothesis that the perception of chest pain may be triggered not only by the nociceptive stimulation of the ischemic heart but also by extracardiac sources. Depressive mood state, when concomitant with cardiac disease, is shown to intensify perceived chest pain.

Assessment of the patient with chest pain in the accident and emergency department

This article will review measures enabling emergency staff to identify patients with chest pain who are likely to need admission to a cardiac care unit, in particular those with manifestations of acute ischaemic heart disease--acute myocardial infarction and unstable angina. Other non-cardiac causes of chest pain will also be discussed.

Pain assessment in acute myocardial infarction patients

The purpose of this study was to investigate the pain intensity and duration, and to assess the pain control intervention, in patients with acute myocardial infarction (AMI).

METHODS

Ninety-seven patients (18 diabetics and 79 non-diabetics) admitted to the hospital with chest pain were included in this study. Pain was measured on the numerical rating scale (NRS) 0-10, where 0 means no pain and 10 unbearable pain. All patients were followed for 12 hours, after the last chest pain episode. The data were statistically evaluated with the Student's t-test and chi square (chi 2).

RESULTS

The pain in AMI patients with diabetes mellitus was lower in intensity (P < 0.002) and shorter in duration (P < 0.000) respectively, compared with the non-diabetic AMI patients. The intensity of pain in patients with an anterior infarction tended to be higher (P < 0.03) than in those with an inferior infarction. Finally, the systolic blood pressure fell significantly (P < 0.000) 90 min after admission. No other significant differences were found.

Coronary care unit patients' and nurses' ratings of intensity of ischaemic chest pain

In 100 patients admitted to a coronary care unit with a history of chest pain thought to be due to myocardial infarction, the intensity of pain was independently rated by the patient and the primary nurse caring for the patient soon after admission. Pain intensity was assessed using a visual analogue scale designed to yield a score of 0-100. 10 experienced coronary care nurses who had participated in a short programme of pain assessment and management were included in the study. A strong positive correlation between the patients' and nurses' ratings was found. Possible explanations for these findings are discussed.

Diagnostic potential of chest pain characteristics in coronary care

OBJECTIVES

To characterize and quantitate the experience of presenting chest pain in coronary care patients in terms of intensity, quality, localization and extension of pain.

DESIGN

Localization of presenting chest pain at a body figure and estimation of intensity according to the Borg CR-10 scale of five qualities related to pain: (i) aching, (ii) burning, pricking, (iii) pressing, throbbing, (iv) dyspnoea, suffocation and (v) anxiety were done within 24 h from onset of symptoms.

SETTING

Coronary care unit (CCU).

SUBJECTS

Eighty consecutive patients of which 40 suffered from acute myocardial infarction (AMI).

RESULTS

The AMI and non-AMI groups did not differ with regard to (i) the intensity of chest pain being mainly of moderate degree and (ii) the mean number of qualities of the presenting chest pain that were between 3 and 4. Patients with AMI reported extension of chest pain over a wider body area than patients in the non-AMI group (P < 0.0001). A second type of chest pain in addition to the major type of chest pain was reported by only 25% of the patients with AMI compared to 68% in the non-AMI group (P < 0.0001).

CONCLUSIONS

Intensity, quality and localization of presenting acute chest pain in patients admitted to the CCU do not differentiate between patients with or without AMI. Extension of pain over a major part of the chest-related body surface and the absence of secondary pain appear to identify at least half of the patients with ongoing AMI.

Impact of early thrombolysis on chest pain score reflecting myocardial ischemia in relation to various markers of ischemic damage. TEAHAT Study Group

We randomized 352 patients with pain suggestive of acute myocardial infarction who were seen less than 3 h after onset of symptoms to either tissue plasminogen activator or placebo. The impact of treatment on chest pain score was assessed during the first 24 h and related to limitation of final myocardial damage as assessed by various indirect markers. The most marked effect of tissue plasminogen activator was observed in the chest pain score being reduced by 43% in the tissue plasminogen activator group as compared with placebo. Limitation of infarct size with tissue plasminogen activator reached the following percentage values when various methods were used: maximum serum lactate dehydrogenase I activity, 32%; vectorcardiography (QRS vector difference), 20%; electrocardiography (Palmeri score), 20%; ejection fraction, 9%. We conclude that early thrombolysis in acute myocardial infarction reduces the severity of chest pain by nearly 50%. The effect on chest pain is much more marked as compared with the effect on various markers of the final ischemic damage.

Reduced consumption of analgesics in patients with diabetes mellitus admitted to hospital for acute myocardial infarction

In a case-control study, the consumption of analgesics was analysed in 39 patients with diabetes, admitted with acute myocardial infarction (MI). The control group comprised of non-diabetics with MI was computer-matched to the diabetic group with respect to age and sex as well as enzyme-estimated size of the infarction. The median number of injections of opioid analgesics in the diabetes and non-diabetes groups was 2 and 5, respectively (0.01 less than P less than 0.05), and the median consumption of morphine was 20 mg and 35 mg, respectively (0.01 less than P less than 0.05). There was no statistically significant trend for the duration of pain to be shorter in the diabetes group. There was no difference between the two groups with respect to number of patients with Q-wave infarct, initial heart rate-blood pressure product or body weight, all of which are possible confounders. We conclude that diabetics admitted with acute myocardial infarction have a lower consumption of analgesics than non-diabetics.

The effect of streptokinase on chest pain in acute myocardial infarction

Treatment with intravenous streptokinase is known to restore blood flow to the ischaemic myocardium in patients with acute myocardial infarction. However, little is known about its effect on chest pain. In a retrospective cohort study, 76 patients treated with streptokinase were compared to 76 patients not treated with streptokinase. All patients had acute myocardial infarction and less than 6 h of cardiac symptoms. Patients treated with streptokinase had a significantly lower need for nicomorphine (median 20 mg) than patients not treated with streptokinase (median 41 mg). Correspondingly, the median duration (3.5 h) of pain was reduced significantly in patients treated with streptokinase compared to patients not treated (24 h). We conclude that intravenous streptokinase given in the acute phase of myocardial infarction is effective in reducing the duration of cardiac chest pain.

Buccal versus intravenous nitroglycerin in unstable angina pectoris

The clinical syndrome of unstable angina includes patients with the first onset of angina, change in a previous stable pattern or the development of chest pain at rest. Administration of intravenous nitroglycerin is established therapy in unstable angina. Buccal nitroglycerin has been introduced as an alternative means of administering nitroglycerin, which provides relief of anginal pain within 2 to 3 min and a sustained effect for 3 to 5 h. Twenty-nine patients admitted to the coronary care unit due to unstable angina were randomized to receive treatment with nitroglycerin i.v. for 24 h or buccal nitroglycerin every 4 h. Therapy was titrated according to haemodynamic effects. The mean dose of buccal nitroglycerin was 4.42 mg versus 0.45 micrograms.kg-1.min-1 in the intravenous group. The efficacy of treatment was similar in the two groups. Buccal nitroglycerin appeared to cause fewer adverse effects, especially less haemodynamic intolerance and headache, although the differences were not significant. Repeated administration of buccal nitroglycerin appears to be a safe and well tolerated alternative to high-dose i.v. nitroglycerin treatment in unstable angina pectoris.

Myocardial infarction pain: systematic description and analysis

The aim of the study was to describe various components of pain in suspected acute myocardial infarction (MI). Ninety-four patients admitted to a Coronary Care Unit (CCU) complaining of chest pain with the preliminary diagnosis suspect MI were included in the study. Thirty-eight subjects were eventually diagnosed as having MI and 56 subjects as non-MI. A comparison of chest pain description was performed between MI and non-MI subjects. The Pain-o-meter (POM) and the Visual Analogue Scale (VAS) were used to assess pain intensity. MI patients reported more intense sensory and affective pain than non-MI patients. MI patients also reported more intense affective pain than sensory pain, whereas non-MI patients reported just the opposite. The number of affective words chosen by MI patients differentiated them more clearly from non-MI patients than any other factor in the pain description. Pain intensity was significantly correlated to the estimated size of the infarct.

The nursing assessment of the patient with cardiac pain on the coronary care unit

The accurate and swift assessment of cardiac pain is an essential requirement to prevent and relieve potential complications of myocardial ischaemia and infarction. Whilst on the coronary care unit, it is the nurse who maintains constant 24 hour contact with the patient, and offers first line treatment for pain control and relief of symptoms. In order to improve the quality of care given by nursing staff, an appropriate pain assessment tool is essential. A number of assessment tools are described and their potential and actual use on the coronary care unit evaluated. Given the limited applicability of those discussed for use with cardiac pain, the need for an accurate pain assessment tool remains an essential requirement for the coronary care nurse, to ensure that patient care reaches its highest potential.

Treatment of pain in acute myocardial infarction

The treatment of pain in acute myocardial infarction varies with local practice. Narcotic analgesics are still the usual treatment in many hospitals. Knowledge of optimal doses, duration of pain relief, and time between drug administration and pain relief is inadequate. Many studies indicate that the relief of pain is often incomplete after treatment with narcotic analgesics. There is often a need for alternative treatments. Large randomised studies consistently show that beta blockade, initially given intravenously and then orally, relieves pain and reduces the need for analgesics. Studies also indicate that early administration of streptokinase and glyceryl trinitrate relieves pain. There is evidence that drugs that limit ischaemic damage also relieve pain.

Variability of chest pain in suspected acute myocardial infarction according to subjective assessment and requirement of narcotic analgesics

In 653 patients with suspected acute myocardial infarction the course of pain according to subjective assessment and morphine requirement is described. Patients were asked to score pain from 0-10 until a pain-free interval of 12 hours appeared. Different categories of patients constructed from clinical aspects were compared. Although the variability between groups was fairly small, subgroups were found in which the initial intensity of pain was more marked and the duration of pain was longer. Thus patients with larger infarcts according to maximum serum enzyme activity and patients with Q-wave infarction had more severe pain initially and also a longer duration and a higher morphine requirement compared with patients with a lower serum enzyme activity or a non-Q-wave infarction. Other groups with a more severe course of chest pain were those with more intensive pain at home, electrocardiographic signs of acute myocardial infarction on admission to hospital, and finally those with a high systolic blood pressure or a high rate-pressure product on admission to the Coronary Care Unit. We thus conclude that there is a variability of chest pain in suspected acute myocardial infarction and that there are defined groups of patients in which a more severe course of chest pain could be expected.

Chest pain in acute myocardial infarction: a descriptive study according to subjective assessment and morphine requirement

In 722 patients with suspected acute myocardial infarction (MI) we have tried to describe the course of chest pain according to their own assessment and morphine requirement. Patients were asked to score pain from 0-10 every second hour after arrival in the coronary care unit (CCU) and also to score their maximal pain at home. A very high intensity of chest pain was observed at home (mean score 7.1). At arrival in the CCU the mean pain score already had declined to 1.8, although 51% still had chest pain. Pain score declined successively during the first 12 hours in the CCU. At 24 hours after arrival, 20% still had some chest discomfort. In one quarter of the series a score of more than 0 was observed later than 24 hours after arrival in CCU. Patients developing definite MI had, as expected, a longer duration of pain and a much higher requirement of morphine compared with those with no MI. The difference between MI and no MI patients regarding subjective assessment of the initial intensity of pain at home and in hospital was, however, surprisingly low.