How long should patients with suspected myocardial infarction be under observation in hospital?

Out of 368 patients admitted to hospital for chest pain and suspected acute myocardial infarction, 267 were discharged within 24 hours on the basis of the clinical picture, electrocardiogram, and serum activities of aspartate transaminase, alpha-hydroxybutyrate dehydrogenase, and creatine phosphokinase. The patients were followed up for 28 days, during which 17 were readmitted, two of them twice and one three times. Two of the patients were readmitted with non-fatal acute myocardial infarction, and two died. The patients had been primarily divided into two groups: those admitted with presumably non-coronary chest pain (77 patients) formed group 1 and those with obvious coronary chest pain (190 patients) group 2. Both deaths occurred in patients in group 2 but the incidences of events during the follow-up period were otherwise similar in the two groups, and some patients in both groups may have had small acute myocardial infarctions when first admitted. The decision to keep in hospital or discharge a patient with chest pain of recent onset can be made within 24 hours of admission. To discharge the patient acute myocardial infarction need not necessarily be excluded and conventional tests are enough to enable a decision to be made.     

Shortened bleeding time in acute myocardial infarction and its relation to platelet mass.

The bleeding time, using the Simplate method, horizontal incision, and venostasis, was measured in a study of 51 patients admitted to a coronary care unit within 12 hours of the onset of chest pain. The bleeding time was significantly shorter in the 28 patients who were found to have definite myocardial infarction compared with the 23 others with chest pain but no definite infarction (p less than 0.0005). A bleeding time of less than 212 seconds correctly classified 84% of patients (sensitivity for definite myocardial infarction 89%) presenting to the coronary care unit with chest pain. Multiple regression analysis showed the bleeding time in all patients to be determined independently (and with high significance) by the following variables in order of importance: diagnostic group, platelet mass (platelet count X mean volume), and age. Packed cell volume was not a significant determinant. In the group with definite myocardial infarction considered alone the same order of variables was observed in predicting bleeding time, but none of them was significant. A major variable reducing bleeding time in acute myocardial infarction remains to be determined. There was no association between bleeding time and creatine phosphokinase activity or infarct size in the group with definite myocardial infarction.     

Hospital Mortality in Acute Myocardial Infarction

All 757 patients with acute myocardial infarction admitted to the three public hospitals in Auckland during one year were studied. About 7% died from cardiac arrhythmia four days or more after the onset of infarction. These patients had severe infarcts with circulatory failure on or shortly after admission to hospital. Late death from arrhythmia in patients recovering from circulatory failure may in many cases be preventable with anti-arrhythmic drugs.     

血清CREG蛋白在急性心肌梗死早期的表达研究

目的：探讨血清中CREG蛋白在急性心肌梗死发作早期的表达情况,尝试为临床心肌缺血的极早期诊断提供一种新的血清标志分子。方法：在2010年6月至2010年11月期间,入选在沈阳军区总医院心内科住院治疗的急性ST段抬高型心肌梗死患者50例及非AMI对照50例,于AMI组胸痛发作后的不同时间点采血测定CK、CK—MB、LDH和cTnT,同时应用Westem blot技术测定血清中CREG蛋白的含量,并与对照组比较。结果：AMI组发病72小时内的血清中CREG蛋白表达均较对照组有不同程度的增高（P〈0．05）。胸痛开始2h内,AMI组血清中CREG的含量即明显增高,其在2h、4h及6h的含量显著高于对照组（P〈0．001）。在胸痛已经发作2小时内,两组间血清cTnT、CK、CK-MB及LDH水平比较无统计学意义（P〉0．05）。结论：CREG在AMI患者血清中的表达增高．其在血清中表达时间早于cTNT及CK-MB。     

Prospective evaluation of eligibility for thrombolytic therapy in acute myocardial infarction.

OBJECTIVES--To determine the proportion of patients presenting with acute myocardial infarction who are eligible for thrombolytic therapy. DESIGN--Cohort follow up study. SETTING--The four coronary care units in Auckland, New Zealand. SUBJECTS--All 3014 patients presenting to the units with suspected myocardial infarction in 1993. MAIN OUTCOME MEASURES--Eligibility for reperfusion with thrombolytic therapy (presentation within 12 hours of the onset of ischaemic chest pain with ST elevation > or = 2 mm in leads V1-V3, ST elevation > or = 1 mm in any other two contiguous leads, or new left bundle branch block); proportions of (a) patients eligible for reperfusion and (b) patients with contraindications to thrombolysis; death (including causes); definite myocardial infarction. RESULTS--948 patients had definite myocardial infarction, 124 probable myocardial infarction, and nine ST elevation but no infarction; 1274 patients had unstable angina and 659 chest pain of other causes. Of patients with definite or probable myocardial infarction, 576 (53.3%) were eligible for reperfusion, 39 had definite contraindications to thrombolysis (risk of bleeding). Hence 49.7% of patients (537/1081) were eligible for thrombolysis and 43.5% (470) received this treatment. Hospital mortality among patients eligible for reperfusion was 11.7% (55/470 cases) among those who received thrombolysis and 17.0% (18/106) among those who did not. CONCLUSIONS--On current criteria about half of patients admitted to coronary care units with definite or probable myocardial infarction are eligible for thrombolytic therapy. Few eligible patients have definite contraindications to thrombolytic therapy. Mortality for all community admissions for myocardial infarction remains high.     

Early reporting of myocardial infarction: impact of an experiment in patient education.

Many deaths from myocardial infarction occur before medical help is sought. A campaign was mounted in Nottingham ("Nottingham Heartwatch") to encourage early reporting. A total of 13 828 men and women aged 40 and over registered with three general practices were asked to telephone a hospital-based number if they developed chest pain lasting for more than 10 minutes. Patients from study practices reported chest pain earlier after our invitation than they had before and also earlier than patients from control practices. While accepting the advice to call early some patients from the study practices ignored our special number and telephoned their general practitioner. The calls received on the Heartwatch line yielded a lower percentage of definite and probable infarcts than the calls received by the patients'' own doctors. The way in which the characteristics of the study practices might have influenced this difference is discussed since it has considerable implications for larger-scale attempts to bring patients with suspected myocardial infarction under medical care at the earliest opportunity.     

Sudden Death in Hospital after Discharge from Coronary Care Unit

In a group of 339 patients with acute myocardial infarction treated in a coronary care unit, 273 left the unit while improving and were expected to leave hospital alive; 23 had a cardiac arrest or died suddenly while still in hospital—17 died immediately or after temporary resuscitation and six were resuscitated to leave hospital alive. Ventricular fibrillation was found in 13 of the 20 patients attended by the cardiac arrest team. The incidents were scattered from the 4th to the 24th day after the onset of infarction. Risk factors in these “late sudden death” patients were compared with the 250 patients who left the unit while improving and did not die or suffer cardiac arrest. The patients susceptible to late sudden death were characterized early in their hospital course by the findings of severe, predominantly anterior infarction, left ventricular failure, persistent sinus tachycardia, and frequent ventricular arrhythmias. It is suggested that such patients be chosen for prolonged observation in a second-stage coronary care unit.     

Cardiac catheterisation by the Judkins technique as an outpatient procedure.

OBJECTIVE--To assess the safety and cost benefit of left heart catheterisation by a modified Judkins technique performed as a day patient procedure. DESIGN--Review study of case notes of consecutive patients examined by the procedure over three years (January 1984 to December 1986). SETTING--Outpatient referrals in a regional cardiac centre within a district general hospital. PATIENTS--Nine hundred patients aged 18-76 (mean 54) selected at a previous clinic as suitable for the procedure. MAIN RESULTS--Eight hundred and fifty patients (94.4%) were discharged home on the day of the procedure. Forty others (4.4%) could not be discharged owing to complications during or just after the procedure. Of these patients, two died (0.2%), six suffered a myocardial infarction (0.7%), and two had major vascular complications. The remaining 30 patients were admitted because of chest pain without infarction (10 cases), minor vascular incidents (six), haemorrhage at the puncture site (five), arrhythmia (four), pulmonary oedema (three), and contrast reaction (two). Ten patients were admitted for either urgent coronary artery bypass grafting or social reasons. CONCLUSIONS--Cardiac catheterisation is safe as an outpatient procedure in most cases. Beds are spared and roughly 35,000 pounds is saved for every 500 procedures performed.     

Report of 24 Cases of Myocardial Infarction Treated at Home

During a four-year period in one general practice 50 patients suffered myocardial infarction; 24 were dead before their general practitioner saw them. Of the surviving 26, 2 were admitted to hospital for social reasons and the others were treated in their homes.One woman suffered a pulmonary embolus on the tenth day of her illness and was admitted to hospital. Three patients were found to develop arrythmias; one of these died. One other patient died, but the others made uneventful recoveries.These results compare well with those obtained by specialist units, perhaps because the advantages of such a unit are balanced by the hazards of transportation to it.     

Meteorological factors and the time of onset of chest pain in acute myocardial infarction

Analysis of the time of onset of chest pain in 2254 patients with a myocardial infarction admitted to a coronary care unit in Leicester during a 10-year period shows an association with temperature and humidity. During both the most cold and humid times of the year, the relationship is a strong one. A generalized linear model with a log link was used to fit the data and the backward elimination selection procedure suggested a humid, cold day might help to trigger the occurrence of myocardial infarction. In addition, cold weather was found to have a stronger effect on the male population while those men aged between 50 and 70 years were more sensitive to the effect of high humidity.     

Radioimmunoassay of serum myoglobin in screening for acute myocardial infarction.

Over an 8-month period 289 patients consecutively admitted to a coronary care unit were studied to assess the value of serum myoglobin determinations by radioimmunoassay in screening for acute myocardial infarction. Of the 289 patients 127 (44%) had an infarction. It was found that when blood sampling was done within 5 to 15 hours after the onset of chest pain this assay had a sensitivity, specificity, and positive and negative predictive values of more than 97%. In this study healthy young adults had a mean serum myoglobin level of 37 +/- 11 (standard deviation) ng/ml, and values above 80 ng/ml were considered positive for acute myocardial infarction. False-positive results can be due to stock, vigorous exercise, skeletal muscle damage and several renal failure, but, except for the last one, these conditions also caused an increase in the serum level of the creatine kinase isoenzyme CK-MB.     

Prognosis of new and worsening angina pectoris.

The natural history of new and worsening angina pectoris was studied in 251 men aged under 70 years. Most were ambulant and all were referred by selected general practitioners to a special hospital clinic over two and a half years. Heart attacks developed in 39 patients, nine of whom died. Seventy-two per cent of the attacks occurred within six weeks of the onset or worsening of angina. Of the 212 patients who did not suffer myocardial infarction and who were clinically reviewed six months after their first attendance 66 had been pain free for the previous three months and 14 had experienced only infrequent attacks of angina. Of the 128 men aged under 65 years who were previously in employment 81% had returned to full-time work six months after their first attendance. A discriminant function analysis using many variables was made to develop a predictive index that would allow patients with new or worsening angina who were likely to develop serious cardiac complications to be identified. This did not prove possible, and the only predictive factor of significance was an increased cardiothoracic ratio. The syndrome of new and worsening angina has a low risk of early death, and many patients are symptom free six months later. In general, emergency coronary arteriography and surgery is not indicated.     

Factors Affecting Admission to a Coronary Care Unit

Of 103 patients with suspected myocardial infarction admitted to an intensive care unit in a general hospital half were admitted within four and a half hours of the onset of symptoms. In general, patients who attended the casualty department were under intensive care sooner than patients who sought attention from their general practitioner before admission. Patients who were seen by a locum from the emergency treatment service at night or weekends were more likely to remain at home until seen the next day by their own general practitioner, compared with patients seen by their own general practitioner initially.     

Myocardial Infarct Size and Mortality Depend on the Time of Day—A Large Multicenter Study

Background

Different studies have shown circadian variation of ischemic burden among patients with ST-Elevation Myocardial Infarction (STEMI), but with controversial results. The aim of this study was to analyze circadian variation of myocardial infarction size and in-hospital mortality in a large multicenter registry.

Methods

This retrospective, registry-based study was based on data from AMIS Plus, a large multicenter Swiss registry of patients who suffered myocardial infarction between 1999 and 2013. Peak creatine kinase (CK) was used as a proxy measure for myocardial infarction size. Associations between peak CK, in-hospital mortality, and the time of day at symptom onset were modelled using polynomial-harmonic regression methods.

Results

6,223 STEMI patients were admitted to 82 acute-care hospitals in Switzerland and treated with primary angioplasty within six hours of symptom onset. Only the 24-hour harmonic was significantly associated with peak CK (p = 0.0001). The maximum average peak CK value (2,315 U/L) was for patients with symptom onset at 23:00, whereas the minimum average (2,017 U/L) was for onset at 11:00. The amplitude of variation was 298 U/L. In addition, no correlation was observed between ischemic time and circadian peak CK variation. Of the 6,223 patients, 223 (3.58%) died during index hospitalization. Remarkably, only the 24-hour harmonic was significantly associated with in-hospital mortality. The risk of death from STEMI was highest for patients with symptom onset at 00:00 and lowest for those with onset at 12:00.

Discussion

As a part of this first large study of STEMI patients treated with primary angioplasty in Swiss hospitals, investigations confirmed a circadian pattern to both peak CK and in-hospital mortality which were independent of total ischemic time. Accordingly, this study proposes that symptom onset time be incorporated as a prognosis factor in patients with myocardial infarction.     

Time delays in provision of thrombolytic treatment in six district hospitals. Joint Audit Committee of the British Cardiac Society and a Cardiology Committee of Royal College of Physicians of London.

OBJECTIVE--To measure the delays between onset of symptoms and admission to hospital and provision of thrombolysis in patients with possible acute myocardial infarction. DESIGN--Observational study of patients admitted with suspected myocardial infarction during six months. SETTING--Six district general hospitals in Britain. SUBJECTS--1934 patients admitted with suspected myocardial infarction. MAIN OUTCOME MEASURES--Route of admission to hospital and time to admission and thrombolysis. RESULTS--Patients who made emergency calls did so sooner after onset of symptoms than those who called their doctor (median time 40 (95% confidence interval 30 to 52) minutes v 70 (60 to 90) minutes). General practitioners took a median of 20 (20 to 25) minutes to visit patients, rising to 30 (20 to 30) minutes during 0800-1200. The median time from call to arrival in hospital was 41 (38 to 47) minutes for patients who called an ambulance from home and 90 (90 to 94) minutes for those who contacted their doctor. The median time from arrival at hospital to thrombolysis was 80 (75 to 85) minutes for patients who were treated in the cardiac care unit and 31 (25 to 35) minutes for those treated in the accident and emergency department. CONCLUSION--The time from onset of symptoms to thrombolysis could be reduced substantially by more effective use of emergency services and faster provision of thrombolysis in accident and emergency departments.     

Five hundred patients with myocardial infarction monitored within one hour of symptoms.

Of 2886 patients monitored during acute myocardial infarction, 500 were observed within one hour of the onset of symptoms. Half of the early admission group were admitted in response to emergency 999 calls and 435 of them travelled in resuscitation ambulances, where surveillance for arrhythmias was instituted. Pulmonary oedema occurred in 130 patients (26%), cardiogenic shock supervened in 60 (12%), and 115 (23%) died in hospital. Ventricular fibrillation was observed in 98 patients (20%). Forty two of them survived to be discharged, including 20 of the 24 with primary fibrillation which had occurred first in hospital. In only one case did primary ventricular fibrillation occur after the first 10 hours of onset of illness. Sinus bradycardia, atrial fibrillation, ventricular tachycardia, and ventricular fibrillation were all observed more frequently in patients admitted within one hour after the onset of symptoms than in those admitted later. An element of selection is inevitable when early admission is encouraged by the existence of a resuscitation ambulance system; this will depend in part on the early recognition of risk and the geographical location of the attack. These factors may bias the group towards relatively high risk. Nevertheless, prompt admission after myocardial infarction should improve survival by permitting successful management both of ventricular fibrillation and of other arrhythmias which may influence short term and long term prognosis.     

Prognosis of patients with "chest pain ?cause".

All 662 patients admitted to the two coronary care units in Nottingham during 12 consecutive months were followed up prospectively for one year. At the time of discharge from hospital they were categorised according to set criteria into the following diagnostic groups: definite, probable, or possible myocardial infarction; ischaemia heart disease without infarction; chest pain ?cause; and other diagnoses. Eighty-nine patients (13% of admissions) were categorised as having chest pain ?cause. No deaths occurred among these patients during the observation period, although two were readmitted with myocardial infarction. Patients with chest pain ?cause had few problems during the year after admission, and at the end of that time 75% were in their original employment. Patients admitted with ischaemic heart disease had a similar death rate (between six weeks and one year after admission) to those with myocardial infarction, and only 36% were in their original employment one year after admission. Chest pain ?cause is a clinically useful diagnostic category to which patients may be allocated after only simple investigations.     

Duration of chest pain associated with acute myocardial infarction: a predictor of long-term prognosis.

This paper describes 109 patients who had their first myocardial infarction and were then followed up for 3 to 8 years. The following data were collected at the time of the infarction: duration and severity of chest pain, type of infarction and peak SGOT (serum glutamic oxaloacetic transaminase) level. The duration of chest pain has previously been shown to correlate with infarct size. Duration of chest pain, age and peak SGOT level were found to be the most important predictors of survival. None of the other independent variables contributed further to survival when the effects of duration of pain, age and SGOT level were taken into account. However, there was a significant association between pain duration and functional status. These data suggest that the duration of chest pain during first myocardial infarctions is a predictor of long-term prognosis and probably of functional status.     

Acute Myocardial Infarction in Doncaster. II—Delays in Admission and Survival

The speed of admission of patients with suspected acute myocardial infarction was observed over a period of 12 months during which a “no refusal” coronary care scheme was functioning, with emphasis on minimizing delay. During the same period the duration of survival of cases diagnosed as coronary thrombosis by the coroner''s pathologist was measured. Comparison of the two series shows that 75% to 80% of the coroner''s cases had died before the median time of notification of the general practitioner by those patients referred to hospital.We argue that the provision of mobile coronary care on request from general practitioners is unlikely to have an appreciable effect in preventing deaths from acute myocardial infarction outside hospital.     

Evaluating a new graphical ordinal logit method (GOLDminer) in the diagnosis of myocardial infarction utilizing clinical features and laboratory data

OBJECTIVE: We used a new graphical ordinal logit method (GOLDminer) to assess a single cardiac troponin T (cTnT) analysis at the time of admission (first generation monoclonal; Roche BMC Corp., Indianapolis, Indiana), the character of chest pain, and electrocardiographic (ECG)findings in predicting the likelihood of acute myocardial infarction (AMI) in patients presenting with suspected myocardial ischemia. The final diagnosis of AMI was based on serial ECG findings and evolution of CKMB isoenzyme levels in conjunction with clinical findings. SUBJECTS: The study population consisted of 293 consecutive patients who presented at a mean of six hours after onset of chest pain or associated symptoms warranting a "rule-out" for AMI assessment to a university-affiliated community hospital. RESULTS: The odds-ratio for an elevated cTnT (> 0. 1 ng/ml) in AMI was 22.2:1. There was an association between typical chest pain and cTnT (chi square = 78.23, p < .0001) and between abnormal ECG findings and cTnT (chi square = 108, p < .0001). The cTnT yielded diagnostic benefit in addition to chest pain characteristics and ECG findings in AMI. We present the odds-ratios for the combined features in GOLDminer plots. CONCLUSION: We demonstrate how the odds-ratios for AMI are obtained after scaling continuous to ordinal the values for a single cTnT determination alone and with other features in patients presenting with chest pain.