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Journal of the New Zealand Medical Association, 21-April-2006, Vol 119 No 1232

Early recognition and early access for acute coronary syndromes in New Zealand: key links in the chain of survival

Helen Tanner, Peter Larsen, Nigel Lever, Duncan Galletly

Abstract

Aims We studied the behaviour of patients prior to admission to hospital with symptoms of acute coronary syndromes, and what barriers may exist to early recognition of these symptoms and to early activation of emergency medical services.

Methods Over a 7-week period, we interviewed 100 patients admitted to the Cardiac Care Unit in Wellington Hospital with suspected acute coronary syndromes.

Results Within 5 minutes of symptom onset, 46 of 100 patients believed they were having a heart attack. Sixty-two of the patients believed that they had a cardiac-related problem. Patients took a median time of 90 minutes (range 0–9600 minutes) to contact a health professional from the time of symptom onset; and a median time of 228 minutes (range 33-9633 minutes) to arrive at hospital. We observed significant differences in both these end-points according to which health professional was contacted first. Patients who presented directly to hospital arrived significantly faster (median 72 minutes) than those who first called an ambulance (180 minutes) or contacted a general practitioner (485 minutes) (p=0.001, Kruskal Wallis test).

Conclusions Considerable delays exist in the presentation of patients with symptoms of ACS to hospital. These delays are multifactorial, but the psychological intimidation of the 111 telephone system and delays incurred by inappropriate out-of-hospital management of patients with chest pain are probably significant. It is likely that these delays contribute to mortality from acute coronary syndromes.

The 1992 American Heart Association Guidelines described early access to emergency medical services (EMS), early basic cardiopulmonary resuscitation, early defibrillation, and early advanced cardiac life support as four independent links in the chain of survival required to optimise survival from out of hospital cardiac arrest.1

Since the publication of that guideline, the concept of the chain of survival has been widely promoted by resuscitation councils throughout the World. Following the publication of the 2000 Consensus on Science document, which reiterated the importance of the four links,2 a supplement in the Annals of Emergency Medicine discussed the 1999 Evidence Evaluation Conference3 which recommended the addition of up to three links in the chain of survival; “early prevention” and “early recognition” of cardiac symptomatology added prior to early activation of EMS and “rehabilitation” added at the end of the chain of survival.

There has been widespread recognition that the time taken to access EMS is a key predictor of mortality for patients suffering acute coronary syndromes (ACS),4,5 with delays as short as 30 minutes significantly increasing mortality rates at 1 year.6,7 In addition, it has been estimated that 50% of those who die from ACS do so within 1 hour of symptom onset.8

It is therefore essential that those suffering ACS are in close proximity to a defibrillator as soon as possible and, in the event of an acute myocardial infarction, angioplasty or thrombolysis is commenced as soon as possible. The reduction in arrhythmic death by availability of defibrillation, and infarct size by early thrombolysis, are substantial benefits of early access to advanced care. With these thoughts in mind, the addition of the early recognition link in the chain of survival was suggested: “The early access link in the current chain of survival implies but does not specifically address early recognition. Adding early recognition to the chain of survival would place greater emphasis on the early signs of heart attack ... which would provide victims with a greater chance of survival”.3

To strengthen the chain of survival in the community, it is necessary to understand how patients think and act when experiencing symptoms of ACS. This present study was conducted to identify what patients do prior to admission to hospital with symptoms of ACS, and what barriers they describe to early recognition and to early activation of the EMS

Methods

Study design—The study was conducted over a 7-week period on all patients admitted to the Cardiac Care Unit in Wellington Hospital with suspected acute coronary syndromes. Patients transferred from other centres were excluded from the study. Patients were interviewed using a structured questionnaire.

Definitions and criteria used for the analysis—

Time of initial symptoms was taken as the self reported time of onset of symptoms. For patients who reported symptoms that were initially intermittent and subsequently constant, the onset time was defined as the time symptoms changed from intermittent to constant.

Time to contact a health professional was defined as the time from symptom onset to the time at which a health professional was first contacted, either by telephone or in person.

Arrival at hospital was the time from symptom onset to the time of physical arrival at the emergency department.

Patients were asked to score pain and anxiety at the onset of symptoms using a scale from 1 to 10, where “1” represented no pain or anxiety and “10” represented the worst possible pain or anxiety.

In the presented data, patients were classified as having have had a previous myocardial infarction (MI) if they stated that they believed they had suffered a previous heart attack and classified as having previous angina if they believed that they had a history of angina.

Symptoms were defined as typical if they included central chest pain or left chest pain, and atypical if they did not.9

The criteria used for final diagnosis were:9,10

STEMI (ST elevation myocardial infarction): Positive troponin-T assay and evidence of ST segment elevation on the electrocardiogram (ECG).
NONSTEMI (Non-ST elevation myocardial infarction). Positive troponin-T assay with no evidence of ST segment elevation on the ECG.
Unstable angina: Negative troponin-T assay but the ECG showed evidence of ischaemic changes.
Non cardiac diagnosis: Negative troponin-T assay and no evidence of ECG changes.

To maintain consistency in interpretation of ECG changes, all ECGs were reviewed by one cardiologist (NAL).

Statistical analysis—Relationships between continuous variables were examined using Spearman rank correlation test, between group comparisons were performed using Mann Whitney U test (2 groups) and Kruskal Wallis test (3 or more groups). All tests were performed using Statview 5 (SAS, Cary, NC, USA).

Results

Over a 7-week period, 108 patients were admitted to the Cardiac Care Unit with an suspected acute coronary syndrome. Eight patients were excluded from the study, six because of language difficulties, one was discharged prior to being interviewed, and one died prior to interview. Patient characteristics are given in Table1.

Table 1. Demographic information of the patients in the study

Age [mean (range) in years] Sex (male/female)	65 (32–88) 69/31
Final diagnosis STEMI Non- STEMI Unstable angina Non cardiac	16 43 26 15
Previous history Acute MI Angina Hypertension CABG	31 34 46 9

STEMI=ST elevation myocardial infarction; Non- STEMI=Non-ST elevation myocardial infarction; MI=Myocardial infarction; CABG=Coronary artery bypass grafting.

Symptomatology and “early recognition”—Initial symptoms experienced by patients are presented in Table 2. Symptoms were classified as “typical” in 76 patients and “atypical” in 24 patients, respectively.

When asked “where did you initially think your symptoms were coming from,” 62 subjects identified the heart. This response was not statistically related to whether symptoms were typical or atypical.

When asked “did you think within 5 minutes of symptom onset you were having a heart attack?,” 46 patients answered “yes”. Again, this was unrelated to whether symptoms were typical or atypical.

Of the 38 patients who did not believe that their symptoms were related to the heart:

14 believed symptoms were indigestion (most commonly because of previous episodes of “indigestion”);
9 believed symptoms were musculoskeletal (most commonly because of increased exercise or exertion prior to the onset of symptoms); and
8 reported that they did not know what was causing their symptoms.

When asked to describe symptoms they believed were associated with a heart attack, patient’s responses are given in Table 3. The most common misconception, in relation to the symptoms actually experienced, was the expectation that chest pain would be very severe. Although 56 patients described likely symptoms similar to those they initially experienced, these patients were not more likely to have believed that they were having a heart attack within 5 minutes of symptom onset.

In an attempt to relieve initial symptoms, 33 patients took glyceryl trinitrate (GTN), 18 rested, 10 took an antacid, 7 exercised (4 of whom believed they had a cardiac-related problem), and 32 did nothing. Only 3 patients took aspirin.

Table 2. Initial patient symptoms

Pain
Central chest pain only
Central chest pain with radiation
Left chest pain only
Left chest pain with radiation
Right chest pain only
Right chest pain with radiation
Other

Shortness of breath
Tiredness
Other

Pain quality
Tightness
Burning
Sharp
Pressure
Ache
Dull
Heaviness
Other

91
31
25
10
9
3
3
10

2
3
4

16
14
15
12
11
7
7
9

Table 3. Patients’ belief about the symptoms associated with heart attack

Symptom	n
Chest pain plus at least one other symptom Chest pain only (note that 25 patients believed chest pain needed to be severe) Shortness of breath Did not know Collapse Paralysis Arm pain	36 38 13 8 2 2 1

Contacting a health professional: “early activation of EMS”—We used time to contact a health professional, and time to arrive at hospital, as the two primary measures of adequacy of activation of the emergency medical services. This data is presented in Table 4. We observed significant differences in both time to contact a health professional (p=0.01, Kruskal Wallis test) and time to arrive at hospital (p=0.001, Kruskal Wallis Test) according to which health professional was contacted first. Those who telephoned a GP made contact with a health professional most rapidly; those who presented directly to hospital arrived at hospital most rapidly.

Table 4. Activation of emergency medical services (EMS)

Variable	n	Time to contact health professional	Time to arrive at hospital
All patients	100	90 minutes (0–9600)	228 minutes (33–9630)
Telephoned hospital	4	81 minutes (5–150)	170 minutes (90–248)
Presented directly to hospital	8	72 minutes (5–2385)	72 minutes (5–2385)
Telephoned GP	14	15 minutes (0–1740)	305 minutes (34–2505)
Presented to GP	33	300 minutes (0–4140)	485 minutes (115–4340)
Telephoned ambulance		39 minutes	112 minutes (0–1072)

Median time taken in minutes (range) for patients to contact a health professional, or to arrive at hospital from the time of symptom onset. Values are given for all patients, and by mode of contacting a health professional. Note that 2 patients contacted a health professional through private consultations and arrived at hospital 155 and 9630 minutes after symptom onset.

Time to arrive at hospital correlated inversely with the degree of initial anxiety (r=-0.29, p=0.003, Spearman rank correlation) and correlated positively with age (r=0.26, p=0.009, Spearman rank correlation) but did not differ according to gender, belief that the problem was cardiac related, previous MI, or previous angina.

When asked why they chose to contact a health professional, 34 said it was because they were not getting better, 4 because they were getting worse, and10 because they had had similar episodes previously. For 22 patients, someone else had made the decision to contact a health professional; in 14 of these patients, a member of the immediate family made contact.

Fifty-seven patients said that they hesitated before contacting the health professional of their choice. When asked why they hesitated, 17 said they did not want to bother the health services, 15 thought their condition was not serious enough, 15 thought their symptoms would go away, and 7 reported a dislike for hospitals.

When asked why they chose to contact a specific health professional, those who contacted the ambulance (39) cited past medical history (12), previous education (11) and seriousness of their condition (8).

Those who contacted the hospital (12) cited seriousness of their condition (6), and those who contacted a GP (47) did not believe their condition was serious (27) or thought that the ambulance and hospital system was too busy (6).

Four patients telephoned a hospital, and all were told to call an ambulance immediately. Fourteen patients phoned a GP initially, and 5 of these were told to call an ambulance. Seven patients were told to come to see the GP immediately, one was told to ‘wait an hour and call back if symptoms had not improved’, and one was told to ‘get a blood test the following morning, and then see the GP’.

Forty-two patients presented to a GP prior to admission to hospital; 31 were referred to hospital following an examination, a median time of 31 minutes (range 4-180 minutes) after initially being seen by the GP. Eleven patients were sent for blood tests (1 prior to seeing the GP, 10 following a GP visit) and were only referred to hospital following a positive troponin-T test.

The 10 patients sent for blood tests following a GP visit were advised to go to hospital a median time of 450 minutes (range 60-1480 minutes) after initially seeing the GP. Nine of the 11 patients sent for blood tests had typical ACS symptoms, 2 had a history of a previous MI, and 2 had previous angina. Two of these patients had STEMI events, and they arrived at hospital 376 and 1137 minutes after initially being seen by their GP.

When asked “what should you do when having a heart attack?”, 80 said ‘one should take an ambulance to hospital’. However, only 17 of the 46 patients who thought they were having a heart attack within 5 minutes of symptom-onset, took an ambulance to hospital.

Twenty-nine patients reported that the symptoms which lead to their hospital presentation were not preceded by any similar episodes, but 71 patients reported that they had experienced similar symptoms ranging from 2 days to 6 months prior to that which lead to hospital admission. These previous episodes appeared to resolve spontaneously and did not lead to the patient to present to a health professional.

Discussion

In the current study, we have found significant problems associated with two of the early links in the chain of survival, “early recognition” and “early access to EMS”. Patients are slow to recognise symptoms associated with ACS, and are reluctant to rapidly access emergency medical services.

We found that only 46 of 100 patients in the study believed that they were having a heart attack within 5 minutes of symptom-onset. When asked where they thought their symptoms were coming from, 62 replied from the heart. This belief did not result in any difference in subsequent behaviour.

Patients in the current study did not gain rapid access to the security of the hospital or emergency medical services. The median arrival time at hospital was 3 hours 41 minutes, with only 25% of patients arriving within 2 hours.

Previous studies in the UK, Australia, and USA have reported median times of 2 hours from symptom onset to hospital presentation.11–14 We found that patients who had higher levels of initial anxiety, and were younger, presented to hospital faster—but choosing to contact a GP resulted in marked delays in arrival to hospital. The delay caused by choosing to contact a GP was unrelated to the delay in initial contact since these patients made initial contact more rapidly than those who chose to activate the EMS.

Several previous studies have found that choosing to visit a doctor outside of hospital introduces significant delays in the time taken to present to hospital.12,13 Although there are many factors that could cause delay at a general practitioner’s office, these were outside the scope of the current study.

Several patients chose to see a GP initially because they were concerned that the hospital and ambulance services were overworked. Over half of the GPs contacted by telephone did not suggest that the patient with chest pain should call an ambulance and be transported to hospital immediately. The GP’s decision to send 11 of 41 patients for blood tests prior to referral to hospital suggests a failure to understand the risks of delay in treatment for patients with AMI.

Nine of these 11 patients had typical symptoms of an acute MI and (in two patients) a previous history of acute MI. The median delay to hospital admission, associated with the request for a blood test, was 9 hours 30 minutes. These results suggest that clear guidelines for EMS activation by GPs (and for situations in which the use of troponin-T assay for out-of-hospital identification of AMI in patients with chest pain may be inappropriate) are needed.

There are several limitations to our present study. We have relied upon recall of symptoms and times by patients and, in doing so, will have introduced an undetermined degree of unavoidable error. It is also possible that the information given to GPs by patients in the study was not the same as they subsequently reported to us, and GP management of some patients may have been significantly influenced by this.

By limiting the study to those patients who have been admitted to a Cardiac Care Unit, we have also introduced a selection bias in favour of patients most likely to have had genuine acute coronary events. If all individuals presenting to any medical service with ACS symptoms were studied, then it is probable that a higher proportion would have a final diagnosis of a non-cardiac condition. It is unclear whether patients with similar ACS symptoms (but who are not admitted to a CCU) act in any way differently from the patients studied here.

Results from this current study suggest that the problems of early access and early recognition are not related entirely to inadequate patient eduction; the majority knew that they should call an ambulance if having a heart attack, and most were able to describe heart attack symptoms. Despite this knowledge, however, patients were unwilling to admit that they could be having a heart attack, and even if they believed this, were unwilling to activate ambulance transport.

The psychological barriers that prevent patients from acknowledging that they could be having a heart attack (and are sufficiently unwell to warrant calling for an ambulance) may be considerable. Media publicity of overworked emergency departments, overstretched ambulance services, and the psychological image of the ambulance service as a “lights and sirens, Rescue 111” service are unlikely to help matters.

Our results suggest that although patients find a call to a general practitioner less threatening than a call to ambulance, the delays associated with contacting a GP are often considerable.

Our results suggest that overall it would substantially reduce the hospital admission delay if ambulatory patients with unrelieved chest pain were simply transported to hospital by a bystander or relative. However the safety of such a proposal could be questioned and it is unlikely that this strategy would find favour with any of the present health professional groups involved with transport and care of these patients.

Alternative strategies to overcome the barriers of recognition and access are therefore needed. These could include:

General practitioners recognising that their primary role in the management of chest pain of possible cardiac origin is to refer the patient on to the emergency services.
Encourage patients (who are unwilling to access the 111 system) to telephone a general practitioner or (if unavailable) the hospital emergency department, Both of these sources should then activate the emergency services if the symptomatology is appropriate.
Promoting a national chest pain telephone line which may be far less threatening to a patient than a 111 call, but could still result in a rapid activation of emergency medical services where described symptoms are at all suggestive of ACS.
Promoting an ambulance-based mobile assessment system whereby an appropriately trained health professional could assess a patient’s symptomatology and ECG in their home or workplace and then decide whether formal ambulance transport on-site thrombolysis is warranted.
Laboratories could justifiably query out-of-hospital requests for acute troponin-T assays.
Ongoing audit, by coronary care units, of the symptom onset to hospital arrival times.

In summary, considerable delays in the arrival of patients with acute MI to hospital are occurring. These delays are multifactorial, but the psychological intimidation of the 111 telephone system and delays incurred by inappropriate use of troponin-T as a diagnostic tool for out-of-hospital chest pain are probably significant.

It is likely that these delays contribute to arrhythmic mortality from AMI and infarct size through delays in defibrillation, angioplasty, and thrombolysis. Given that chain of survival in a community is only as strong as its weakest link, we may well need to look at ways of promoting early recognition and early access to emergency medical services as being every bit as important as early CPR and early defibrillation.

Author information: Helen Tanner, House Surgeon, Wellington Hospital; Peter D Larsen, Senior Lecturer, Department of Surgery and Anaesthesia, Wellington School of Medicine, University of Otago; Nigel A Lever, Senior Lecturer, Department of Medicine, University of Auckland, Auckland; Duncan C Galletly, Associate Professor, Department of Surgery and Anaesthesia, Wellington School of Medicine, University of Otago; Wellington

Acknowledgement: This study was supported by the Wellington Surgical Research Trust.

Correspondence: Peter Larsen, Department of Surgery and Anaesthesia, Wellington School of Medicine and Health Sciences, PO Box 7343, Wellington. Fax (04) 389 5318; email: peter.larsen@otago.ac.nz

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