150 Patients with cardiac infarction treated in a coronary unit

History and development of coronary care

The first coronary care units (CCUs) were opened in the 1960s in an attempt to reduce mortality from acute myocardial infarction (AMI). Nurses were closely involved in the development and success of these early units. This paper will provide an overview of the history and development of the CCU, including nurses' crucial involvement in pioneering the first CCUs in the 1960s through to the emerging role of nurses in the care of cardiac patients in the late 1990's.

The structure of emotions during acute myocardial infarction: a model of coping

The present state of medical care for heart attacks, or acute myocardial infarction (AMI), clearly indicates that rapidly and expeditiously seeking definitive medical care will reduce morbidity and prevent mortality. Despite the clearly established advantages of rapid AMI treatment, the time from the onset of acute symptoms of AMI to definitive medical care is often prolonged and individuals with a prior history of AMI and/or coronary artery disease (CAD) extend care-seeking. Behaviors and actions surrounding acute care-seeking are often fraught with complex social, psychological and emotional processes. The purpose of the present paper is to bring together a theoretical and an applied understanding of the interval of time from acute symptom onset to definitive medical care during AMI; and to understand the role of emotions in the care-seeking process. This task is especially important among individuals with a prior history of AMI and/or CHD. These individuals can be seen as experiencing a "spectrum of posttraumatic disturbances", ranging from anxiety to posttraumatic stress disorder and alexithymia. These disturbances contribute to extended care-seeking thereby placing the individuals at greater risk for AMI and sudden cardiac death. Effective intervention requires three elements. First, knowledge is necessary so that individual and lay others can correctly label symptoms and signs of an AMI. Second, it is necessary to provide feasible behaviors that individuals and lay others can use to access definitive medical care. Third, and perhaps most importantly, it is necessary to provide understanding of and skills to cope with the emotional arousal surrounding both the primary traumatic experience of symptoms and signs, potential secondary traumatic consequences of AMI care-seeking and tertiary trauma from the long-term consequences of CHD.

Clinical impact of introducing thrombolytic and aspirin therapy into the management policy of a coronary care unit

PURPOSE

To evaluate the impact of introducing thrombolytic and aspirin therapy into the management policy of a coronary care unit, with particular reference to its effects on the hospital course of nonselected patients with acute myocardial infarction. End points chosen were the utilization of thrombolytic and aspirin therapy, hospital mortality, discharge diuretic requirements, and the incidence of ventricular fibrillation and cardiogenic shock.

PATIENTS AND METHODS

A total of 336 patients with acute myocardial infarction were studied, comprising consecutive admissions to the coronary care unit over two separate 12-month periods: January to December 1986 (n = 158) and September 1989 to August 1990 (n = 178), before and after thrombolytic and aspirin therapy had been introduced into the management policy of the unit.

RESULTS

Thrombolytic and aspirin therapy was given to 87% and 93%, respectively, of all patients in the 1989/1990 cohort. This high treatment rate led to substantial improvements in morbidity and mortality. Thus, comparison of the 1986 and 1989/1990 cohorts showed reductions in hospital mortality (24% to 11%, p less than 0.005), ventricular fibrillation (22% to 13%, p = 0.05), and cardiogenic shock (20% to 6%, p less than 0.001), particularly in patients aged over 60. Reductions in the incidence of lesser degrees of heart failure are reflected in the proportions of patients discharged with diuretic requirements, which declined from 43% in 1986 to 22% in 1989/1990 (p less than 0.001). The duration of hospital stay for patients who survived showed no change between 1986 and 1989/1990, but time spent in the coronary care unit decreased from 3.1 +/- 1.8 to 2.1 +/- 1.4 days (p less than 0.001).

CONCLUSION

The great majority of nonselected patients with acute myocardial infarction are candidates for thrombolytic and aspirin therapy, which can be given safely, leading to profound reductions in mortality and the incidence of major complications, particularly in the older age group.

Improved prognosis since 1969 of myocardial infarction treated in a coronary care unit: lack of relation with changes in severity

OBJECTIVE

To study changes from 1969 to 1983 in the prognosis of patients with acute myocardial infarction treated in a coronary care unit.

DESIGN

Mortality follow up of all patients with definite acute myocardial infarction.

SETTING

The coronary care unit of the Royal Melbourne Hospital, a tertiary referral centre.

SUBJECTS

4253 Patients (3366 men, 887 women) admitted from 1969 to 1983.

MAIN OUTCOME MEASURE

Mortality recorded at discharge from hospital and 12 months after admission.

RESULTS

Details of clinical findings, history, electrocardiograms, arrhythmias, and radiological findings were recorded on admission. Mean ages were 63 for women and 57 for men, and women had haemodynamically more severe infarcts than men. In the later years patients were older and had less severe infarcts. Overall, hospital mortality in men was 16.7% in 1969-73 and 8.5% in 1979-83 and declined in all grades of the Norris and Killip infarct severity indices compared with a constant 19.2% in women. Even after adjustment for age and severity by logistic regression, hospital mortality fell in men by an average of 8% (95% confidence interval 4% to 11%) a year but remained constant in women. By 1983 male mortality was 60% that of women of similar age and comparable severity of infarction. Mortality of hospital survivors at 12 months declined by 7% (4% to 9%) a year in both sexes, even after adjustment for age and severity, with a male to female mortality ratio of about 0.8. New indices were derived to predict mortality in hospital and at 12 months.

CONCLUSION

The observed declines in mortality cannot be explained by changes in severity of infarction or in prognostic characteristics of patients.

The impact of the family and lay others on care-seeking during life-threatening episodes of suspected coronary artery disease

To understand the impact of the family on care-seeking during a suspected episode of acute coronary artery disease (CAD) interviews were conducted with 1102 individuals hospitalized for a suspected myocardial infarction. Analyzing the care-seeking behavior of these individuals within life threatening illness behavior and situational perspectives, bivariate and multivariate analyses revealed that family members, especially a spouse, had both positive and negative influences on the duration of time between acute symptom onset and arrival at a hospital emergency room. To reduce both the morbid and mortal consequences of acute CAD it is recommended that we direct our intervention efforts toward warning the public of situational circumstances which contribute to extended self treatment and evaluation during acute episodes of CAD.

Course of patients discharged early after myocardial infarction

Two hundred and seventy-one (76%) out of 358 survivors of infarction were discharged by the eighth hospital day, and 251 (93%) of them survived to six weeks after discharge. Six of the 20 patients who died between discharge and six weeks did so after readmission and 14 died as outpatients. All these patients who died at home had transmural infarction and four had diabetes. In inpatients successful resuscitation occurred mainly within the first 48 hours, with only three successful long-term results from all the patients who suffered arrest later. This suggests that more prolonged inpatient care would not have reduced the late mortality. These figures justify continuing with an early discharge policy for most patients, but coronary care should probably be more prolonged for patients with diabetes.

Myocardial infarction: a comparison between home and hospital care for patients

To compare the results of home and hospital treatment in men aged under 70 years who had suffered acute myocardial infarction within 48 hours 1895 patients were considered for study in four centres in south-west England. Four-hundred-and-fifty patients were randomly allocated to receive care either at home by their family doctor or in hospital, initially in an intensive care unit. The randomised treatment groups were similar in age, history of cardiovascular disease, and incidence of hypotension when first examined. They were followed up for up to a year after onset. The mortality rate at 28 days was 12% for the random home group and 14% for the random hospital group; the corresponding figures at 330 days were 20% and 27%. On average, older patients and those without initial hypotension fared rather better under home care. The patients who underwent randomisation were similar to those whose place of care was not randomised, except that the non-randomised group contained a higher proportion of initially hypotensive patients, whose prognosis was poor wherever treated. These results confirm and extend our preliminary findings. Home care is a proper form of treatment for many patients with acute myocardial infarction, particularly those over 60 years and those with an uncomplicated attack seen by general practitioners.

Use of a balloon-tipped flotation electrode catheter for cardiac mounting

A new balloon-tipped flotation catheter equipped with two pairs of electrodes has been developed for simultaneous monitoring of cardiac rhythm and hemodynamics as well as for temporary emergency atrial, ventricular and atrioventricular sequential pacing. Experience in 43 patients demonstrates the following: (1) The catheter can be passed and positioned with the tip in the pulmonary artery or its branches at the bedside with the use of fluoroscopy as easily as the standard (Swan-Ganz) catheters. (2) With the catheter in the proper position ans with the use of appropriate filters (proximal, 50 to 300 hertz; distal, 15 to 300 hertz), the intracavity electrograms recorded from the proximal and distal pair of electrodes provide characteristic high right atrial and right ventricular signals, virtually free of noise artifact, baseline drift and respiratory variation, that are particularly suitable for automated on-line monitoring of cardiac rhythm. (3) When indicated, atrial, ventricular or atrioventricular sequential pacing can be initiated without delay. (4) Large artifact-free right ventricular intracavitary signals can be used for reliable and consistent operation of any device requiring QRS triggering mechanisms. (5) Monitoring of pulmonary arterial or pulmonary capillary wedge pressure and withdrawal of blood samples from the central circulation is possible. This device can be particularly useful in patients with hemodynamic difficulties as well as arrhythmias.

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.

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.

The value of monitoring pulmonary artery pressure for early detection of left ventricular failure following myocardial infarction

Flow-directed catheters recorded serial changes in mean pulmonary artery pressure (PA) every 4 to 6 hours in 25 patients during the first 4 or 5 days following acute myocardial infarction. On the basis of the PA on admission, patients were divided into three groups. Patients in group 1 had normal PA (10-20 mm Hg) and maintained a stroke volume index (SVI)>35 ml/min/m 2 , a pulmonary artery oxygen saturation (MVSO 2 )>70%, and a normal cardiac index, arterial oxygen saturation, p H, and P CO CO2 . They developed only minor arrhythmias, no heart failure, and none died. Group 3 consisted of one patient with abnormally low PA (<10 mm Hg) who was hypovolemic. Group 2, those patients with elevated PA (>20 mm Hg) who maintained this elevation over the first 48 hours of monitoring, or showed progressive elevation prior to this, had SVI<35 ml/min/m 2 , MVSO 2 <70%, cardiac index<3 liters/min/m 2 , arterial desaturation, and respiratory alkalosis. They demonstrated clinical evidence of heart failure, had major arrhythmias, and 25% died. Three patients with elevated PA on admission spontaneously returned this pressure to normal over the first 48 hours of monitoring. Each of these patients maintained normal hemodynamics and had a good prognosis. PA was always elevated prior to the usual clinical signs of left ventricular failure. We conclude that PA provides a reliable early objective measure of left ventricular failure and is, therefore, an excellent guide to therapy.

Coronary care in a General Hospital. Results and observations on the first year's work in the unit in the Southern General Hospital, Glasgow

The establishment, staffing and structure and observations made in the first year of the existence of coronary care in an intensive care unit in a general hospital are recorded. Two hundred and twenty eight patients were admitted during the year in whom the diagnosis of myocardial infarction was confirmed. There were 29 deaths in the unit and 14 deaths occurred in the wards of the hospital after discharge from the unit. 49.1 per cent of the patients were admitted within 4 hours of the onset of symptoms and the mean duration of stay in the unit was 86.5 hours. The type of arrhythmia detected in the unit, and the treatment given to the patients both before and after admission to the intensive care unit are described.

Cardiac ballet: repetitions of complex electrocardiographic patterns

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Coronary care unit in a general medical ward

A five-bedded coronary care unit has been set up within a general medical ward without the provision of extra medical or nursing staff. During 30 months 1,000 patients were admitted. Sixty-three developed cardiac arrest; 28 were resuscitated successfully initially; and 18 were eventually discharged. The corresponding figures for the 28 patients with ventricular fibrillation treated by direct current defibrillation were 20 and 12 respectively. The mortality rate during the first three days (the usual length of stay in the unit) was 8.9% compared with 9.7% after transfer to the general ward. It is suggested that these results are comparable with those from more highly staffed purpose-built units.

Value of routine cardiac monitoring in the management of acute myocardial infarction outside a coronary care unit

In a coronary care unit patients and electrocardiographic monitors are under almost continuous observation by trained personnel. This paper suggests that in a general medical ward without this facility routine cardiac monitoring with E.C.G. oscilloscopes is unlikely to lower the overall mortality from acute myocardial infarction. A mortality of 25% for acute myocardial infarction was the same for a hospital without a coronary care unit where monitoring was routinely performed and for two neighbouring hospitals which did not routinely use monitoring during the period of analysis.The need to train personnel in the recognition of E.C.G. monitor tracings and the difficulties associated with monitor alarm systems are emphasized.

The Westminster Hospital coronary unit--experience with 260 patients admitted consecutively with a diagnosis of acute myocardial infarction

In successive years since the opening of a Coronary Care Unit at Westminster Hospital the mortality has been 26 and 20% and for the first 4 months of 1968, 5·3%. Overall mortality for 260 patients was 20%.

Resuscitation has been successful in 59% of cardiac arrests within the unit and in 27% of those outside the unit caused by myocardial infarction. Seventeen patients left hospital alive and well who presumably would not have survived had they been treated at home.

Given efficient nursing staff and a resuscitation team, there can no longer be any justification for the treatment of patients with myocardial infarction anywhere other than in a coronary care unit, where such facilities are made available, providing admission is arranged within 3 days of the infarcting episode. The disadvantage of an ambulance journey to a patient with a recent infarct after this period of time may outweigh the advantage incurred by the coronary care unit.

The Peel Coronary Prognostic Index remains a very useful guide to prognosis in spite of this author's attempts to demonstrate any inaccuracies in its predictions.

A high (20%) ‘misdiagnosis’ rate must be accepted if some patients with bona fide myocardial infarction are not to be excluded from the unit.

The occurrence of 435 deaths reported to Her Majesty's Coroner for Westminster in the relevant period due to myocardial infarction suggests that the time may be ripe for a ‘flying squad’ resuscitation service in London.