Guidelines for the early management of patients with myocardial infarction

Abstract

Method The proposed guidelines were debated and developed by consensus at a workshop sponsored by the British Heart Foundation and held in Cardiff in April 1993. The participants had been chosen by comparing lists of people suggested independently by three clinicians. Among those attending the workshop were general practitioners, representatives of the ambulance service, a nurse, a health educator, epidemiologists, a public health physician, a manager, and hospital doctors from both teaching and district hospitals (see appendix). The meeting consisted of several short presentations followed by discussion. The presentations were augmented by abstracts that had been submitted beforehand. The guidelines were further discussed at an open conference the following day and have been refined during the drafting process by communication with workshop participants. The guidelines are presented in two forms: a list of specific recommendations (see box) and a more detailed text outlining their rationale. The challenge The overall goal is to reduce morbidity and mortality due to heart attack. An essential step is to decrease the interval between the onset of symptoms of a coronary event and the provision of appropriate care, whether this is basic life support, advanced cardiac life support including cardiac monitoring and management of arrhythmia, adequate analgesia, adequate assessment and accurate diagnosis or, where indicated, antischaemic and thrombolytic treatment. Many lives could be saved by minimising delay wherever it occurs in the overall management of patients. The most important components of this aspect of management are prompt resuscitation (defibrillation), analgesia and, where appropriate, thrombolytic treatment. By using data from large, placebo controlled trials it has been estimated that thrombolytic treatment starting in the fourth to sixth hour after onset of symptoms is associated with a saving of 25 lives per 1000 patients treated; in the second or third hour with 27 lives per 1000; and within the first hour with 65 lives per 1000.6 In addition, a more rapid response by health professionals will increase the number of episodes of cardiac arrest that occur in the presence of a doctor or paramedic. This will also lead to increased survival rates. Improvements are required in several areas, including the response of the patient or bystander to symptoms, the response of the general practitioner or ambulance to a call for assistance,7 treatment before arrival at hospital, earlier thrombolytic treatment, and the hospital's response to the admission of a patient with suspected myocardial infarction. Recommendations Patient education “Patient delay” (from the onset of symptoms to calling for help) occurs at the most critical time in the evolution of an acute myocardial infarction. Mass public education campaigns might shorten this time. Such schemes, however, have been disappointing8 and do not seem to produce major long term benefits.9 On the other hand, up to 30% of patients presenting with a myocardial infarction are already known to have coronary heart disease, and such patients at high risk of coronary events, and their close relatives, would benefit from appropriate advice. This advice, perhaps in the form of written guidelines, should form part of coronary rehabilitation programmes. General practitioners, the general public, and relatives of high risk patients should be encouraged to receive training in cardiopulmonary resuscitation according to the European Resuscitation Council guidelines, which emphasise the importance of bystanders immediately contacting the emergency services (999) in cases of suspected cardiac arrest.10 Training cardiac patients and their relatives in such techniques is feasible and does not lead to increased anxiety.11 Patients experiencing chest pain should be encouraged to contact both the ambulance service and their general practitioner; witnesses of an unconscious collapsed patient should telephone for an ambulance rather than attempting to call general practitioners, other relatives, or the police.12 Response of general practitioner and ambulance service General practitioner General practitioners have a valuable role in the management of suspected acute myocardial infarction; their knowledge of the patient may facilitate more accurate diagnosis and more sensitive treatment, and the practitioner's knowledge and experience of drug treatments (including the use of opiate analgesics) is likely to be superior to that of ambulance staff. The general practitioner may not be available immediately, however, and his or her response may be limited by lack of resuscitation equipment. Few general practitioners carry defibrillators when attending patients with chest pain,13 although those who do have reported impressive results in resuscitating patients who develop ventricular fibrillation in their presence.14 Similarly, the use of a 12 lead electrocardiograph is limited in general practice.15 A general practitioner's availability will vary during the day, depending on the clinical workload. Overall, patients admitted to hospital with suspected myocardial infarction have a longer delay before admission if they have been assessed by their general practitioner, rather than an ambulance called for directly.16,17 In most areas, the majority of patients continue to contact their general practitioner first.18,19 A rapid response is possible - median response times by general practitioners were as short as 20 minutes in an observational study of thrombolytic agents given in hospital20 and 10 minutes in a randomised controlled trial of thrombolysis before arrival at hospital.21 Practices need to determine how they will respond without delay to patients experiencing chest pain in the community. This will involve the practice's ancillary staff (receptionists, nurses, office staff), who should have written instructions on what to do when a patient with chest...