Each year, approximately 6 million patients present to emergency departments (EDs) in the United States with complaints of chest pain. Approximately half of these patients are hospitalized for further evaluation. Of those patients who are discharged home, about 11,000 will have had an acute MI (AMI) that was overlooked by their health care provider, accounting for 2% to 8% of all patients with a diagnosis of AMI. Compared with patients who are admitted to the hospital, the mortality rate for discharged patients is nearly double.1,2 Delays in diagnosing AMI are of grave concern to PAs and other clinicians who are tasked with performing initial evaluation of patients presenting with chest pain.
Researchers have found that health care practitioners have an inherent tendency to focus on the classic presentation of AMI when evaluating chest pain. Studies have shown that providers can overlook important considerations in the patient's presentation when the symptoms do not match what they are expecting. This may result in failure to recognize atypical presentations and lead to diagnostic delays.3 Long intervals between symptom onset and treatment of AMI have been associated with serious adverse consequences, including larger infarct size, irreversible cardiac damage, and death.4 While considering other life-threatening conditions that present with acute chest pain, including pulmonary embolism, aortic dissection, and esophageal rupture, providers may miss the diagnosis of AMI altogether.2
Some populations are at greater risk for missed or delayed diagnosis of AMI than others. Such groups include women; elderly patients; and people belonging to certain races, ethnic backgrounds, and cultural groups.1,3,5–19 Patients with comorbid disease, such as diabetes and congestive heart failure (CHF), are at risk for delay in diagnosis due to atypical presentations.4,5,20 Provider overfamiliarity, which can occur with “frequent flyers,” ie, patients who present repeatedly to the clinic or ED, has been shown to result in undue delays in diagnosing AMI. PAs and other providers must remain vigilant in their suspicion and awareness of circumstances that could delay the diagnosis of AMI.20–24
The purpose of this review is to increase awareness among PAs and other providers of factors that have been shown to contribute to delays in the diagnosis of AMI in the ED or clinical setting. The factors examined in this article are commonly associated with atypical presentations, which can lead to errors in diagnostic reasoning on the part of the practitioner. Heightened awareness of atypical presentations will contribute to increased diagnostic acumen and lead to lives saved or potential improvement of patients’ quality of life after diagnosis. Distinguishing between atypical presentation of AMI and other noncardiac causes of chest pain is crucial when deciding whether the patient can be safely discharged or needs further evaluation and testing.
Coronary artery disease (CAD), in conjunction with MI, is the leading cause of death in the United States.25,26 AMI results from cardiac cell death following an interruption in blood supply.25,27,28 Most of the symptoms associated with AMI begin when the cardiac muscle lacks adequate perfusion and the myocardial cells do not receive sufficient oxygenation.25,28 Decreased perfusion may result from an accumulation of cholesterol and plaque in a coronary artery and subsequent reduction in blood flow to tissues beyond the obstruction. Sudden reductions in perfusion can result in thrombosis in a coronary artery and emboli that can lodge in a partially occluded coronary artery. Both events lead to impediment of blood flow and cellular damage. When restricted blood flow persists for 3 to 4 hours or perfusion is absent for 20 minutes, the cardiac muscle becomes ischemic. If the situation is not corrected, cell necrosis and death occur.27,28
When a patient first presents with symptoms of AMI, most clinicians begin by considering the patient's risk factors for CAD and AMI.29 History-taking typically focuses on determining the onset and duration of symptoms, with extra consideration given to those symptoms commonly associated with AMI. The patient's risk for AMI is an important consideration and helps in determining the extent of the physical examination and testing to follow. Risks for AMI tend to be higher in patients who are female or older or who use tobacco products, drink excessive amounts of alcohol, consume a high-fat diet, do not exercise regularly, or have a sedentary lifestyle. Patients with a personal or family history of CAD or MI or who have other concurrent disease, such as diabetes mellitus, hypertension, or hypercholesterolemia, are at risk for AMI. As the number and duration of such factors increases, so does the patient's risk.29
Most often, during the evaluation of these patients, laboratory and imaging tests are obtained after a brief physical examination.27 Three tests are commonly used. An ECG is used to look for abnormal electrical patterns associated with AMI or evidence of cardiac ischemia. Cardiac biomarkers, ie, enzymes released from necrotic heart cells, can be measured by analyzing blood samples. Over time, these enzymes have the potential to reveal evidence of myocardial cell death. Later, radionuclide ventriculography scanning may prove to be helpful in confirming the diagnosis of AMI by demonstrating cardiac abnormalities associated with reduction in coronary perfusion.27
The typical symptoms of AMI include chest pain, which is often described as an uncomfortable pressure, heaviness, or squeezing in the chest. This pain has been classically described as radiating to the neck, jaw, left shoulder, or left arm. Other symptoms that can provide clues to a diagnosis of AMI include shortness of breath, diaphoresis, and nausea.29
ATYPICAL PRESENTATIONS OF AMI
Not all patients experiencing an AMI will have the classic symptoms.29 In addition, some patients experience these symptoms in a different fashion or express discomfort associated with AMI in unexpected ways. Atypical AMI can be more narrowly defined as the presentation of AMI in the absence of chest pain or in the presence of localized pain in the neck, back, jaw, or head. Other atypical AMI symptom manifestations include isolated weakness, diaphoresis, nausea, dyspnea, or cough.30
Patients who present with atypical symptom complexes are more likely to be discharged home without a correct diagnosis and to experience a delay in diagnosis of AMI. Researchers have found that elderly patients, women, patients with comorbid conditions, and patients from certain cultural/ethnic backgrounds are more likely to present with atypical symptoms and more likely to suffer from misdiagnosis.3,5–19 Variations in presentation patterns, especially those that fail to mimic classic patterns or meet the usual expectations, can result in failure to appreciate the significance or origin of the patient's complaints. However, when practitioners are aware of atypical symptom possibilities and relationships associated with certain patient groups, they are more likely to make the cognitive associations needed to reach a correct diagnosis of AMI in a timely fashion.3
Elderly patients Many older patients experience a delayed or missed diagnosis of AMI because they present with atypical symptoms and they are at higher risk for experiencing AMI without pain.5,7,9,15,17 The Rotterdam Study, a prospective population-based cohort investigation conducted in 2006, found the number of missed or delayed diagnoses of AMI was higher in patients aged 74 to 80 years. Researchers were able to demonstrate that as patient age increased, so did the percentage of unrecognized AMIs; this held true until patients reached about 80 years of age.9
One study found that elderly patients experiencing AMI and presenting without chest pain tended to be about 7 years older (74.2 vs 66.9 years old) than others who presented with chest pain.5 A prospective cross-sectional study assessing nearly 2,000 patients found that elderly patients having an AMI were more likely to present without pain. On the other hand, these patients were more likely to experience dyspnea or faintness when having an AMI.7 Similarly, data collected by the Global Registry of Acute Coronary Events (GRACE) between 1999 and 2004 showed that elderly patients tended to present without pain. According to GRACE, as AMI patients increased in age, they were less likely to present with chest pain. Forty percent of AMI patients older than 85 years presented with chest pain versus 77% of AMI patients younger than 65 years. Elderly patients were also more likely to present with dyspnea, diaphoresis, nausea and vomiting, and syncope.15 A summary of symptoms commonly reported by elderly patients experiencing AMI appears in Table 1.
Gender Women are more likely to present with atypical symptoms while experiencing an AMI.1,5,8–11,16 A 2000 prospective clinical trial involving nearly 900 AMI patients showed that women were more likely than men to be discharged home from the ED with a missed diagnosis of AMI.1 The Rotterdam Study found that 54% of women having an AMI were at risk for misdiagnosis compared to only 33% of men.9 Additionally, a large prospective study consisting of more than 400,000 AMI patients found that women were more likely to present with atypical symptoms, particularly lacking symptoms of chest pain, when compared with men.5 A retrospective cohort study consisting of almost 800,000 AMI patients reported that women were less likely to present with chest pain but more likely to present with tachycardia and hypotension.16 Two other studies found that women were more likely to report pain in the arm, neck, back, or jaw; headache; nausea/vomiting; dyspnea; and cough when experiencing AMI.7,10 Patients who are both older and female have even higher levels of missed or delayed diagnoses.9Table 2 summarizes commonly reported symptoms in female patients experiencing AMI.
Cultural/ethnic backgrounds Some patient groups from different cultural/ethnic backgrounds are more likely to present with atypical complaints while experiencing AMI.6,8,12,14,17–19 A study comparing white patients with others of Hispanic, African American, and Asian backgrounds revealed that on the whole, nonwhite patients were at greater risk for delayed diagnosis resulting from atypical presentations. Hispanic patients were least likely to present without chest pain.8 Compared with those who were of Chinese, South Asian, Southeast Asian, and North American Indian descent, white patients with AMI were more likely to have classic midsternal chest pain with pressure. These patients also had a greater probability of associated shoulder/arm pain and diaphoresis. Asians and North American Indians were more likely to present with atypical symptoms, Southeast Asians were more likely to present with confusion, and North American Indians were more likely to present with confusion and syncope.17 A prospective study evaluated nearly 8,000 patients of Southeast Asian and white descent for differences in presentation. This study showed that Southeast Asian patients were more likely to present with atypical chest pain associated with coronary outcomes compared with white patients (59.9% vs 52.5%).18 Another study indicated that white patients are more likely than their African American counterparts to complain of shoulder, neck, and jaw pain. African American patients in this study were twice as likely to complain of dyspnea and fatigue.12
Hispanic patients also have a greater tendency to present with atypical symptoms of AMI. A randomized community trial conducted in 2000 found that Latino men were more likely to describe a “burning sensation in the center of their chest” or a “cramping sensation on the left side” when experiencing AMI.6 A retrospective community-based study of 589 patients revealed that Hispanic Mexican Americans were more likely to report chest pain associated with palpitations and upper back pain when having an AMI and less likely to report arm or jaw pain.14 An additional retrospective survey in 2010 looked at the symptom presentation of AMI patients among African American, Hispanic, and white women. African American women were more likely to present with feeling hot and flushed and complain of indigestion. Hispanic women were more likely to complain of discomfort, including pain in the upper central chest and in the legs; jaw; and arms, particularly the left arm. White women were more likely to present with generalized chest discomfort and back and arm pain than African American patients but less likely to report such complaints than Hispanic patients.19
Atypical symptoms among persons from different cultural/ethnic backgrounds may be partially responsible for delays in diagnosis of AMI because patients describe their symptoms differently. Table 3 summarizes some of the differences that emerged from a review of these studies.
Comorbid conditions Concurrent medical conditions can affect the symptoms patients experience when having an AMI. For example, patients with diabetes mellitus and CHF are particularly vulnerable. Diabetic patients have a greater tendency to present with a “silent MI,” ie, they present without any symptoms of chest pain.5,20 This risk can be compounded when combined with cultural/ethnic concerns. A very large prospective cross-sectional study of more than 400,000 patients found that one-third of patients with a diagnosis of AMI did not have chest pain as a manifestation of their disease. Interestingly, approximately one-third of those patients who were without chest pain had diabetes.5
Researchers in England discovered that black patients from the Caribbean tended to have a higher incidence of diabetes and were more likely to complain of atypical symptoms, including musculoskeletal pain or no pain at all.3 Another study demonstrated that patients with diabetes are more likely than nondiabetic patients to present without symptoms of chest pain when experiencing AMI.11 Similarly, patients with CHF are more likely to present without chest pain. One study showed that about 50% of patients with a history of CHF are prone to atypical presentation of AMI, in which they do not experience any chest pain.11
- Some populations, including women; elderly patients; people belonging to certain races, ethnic backgrounds, and cultural groups; and patients with comorbid disease, such as diabetes and congestive heart failure, are at risk for delay in diagnosis of acute MI (AMI) because of atypical presentations.
- Atypical AMI can be more narrowly defined as the presentation of AMI in the absence of chest pain or in the presence of localized pain in the neck, back, jaw, or head. Other atypical AMI symptom manifestations include isolated weakness, diaphoresis, nausea, dyspnea, or cough. Patients who present with atypical symptom complexes are more likely to be discharged home without a correct diagnosis and to experience a delay in diagnosis of AMI.
- Atypical symptoms among persons from different cultural backgrounds may be partially responsible for delays in diagnosis of AMI because patients describe their symptoms differently.
PRACTITIONER FAMILIARITY WITH THE PATIENT
Being familiar with the patient has led practitioners to underestimate his or her risk for AMI. Studies have shown that the frequency of a patient's visits to an ED can negatively affect interpretation of his or her symptom acuity. In fact, frequent visitors to the ED tend to have a higher level of acuity, are more complex, and have more problems than infrequent users.21–24 When practitioners misjudge the severity of complaints in these patients, the clinicians risk missing clues that can lead promptly to the correct diagnosis of AMI. Some researchers have shown that patients who make frequent use of the ED can become “disliked” by their providers, which can lead to their having a negative impression of the patient. A negative stigma can inadvertently and unknowingly cause the practitioner to be less attentive to the patient's history. This can further increase the risk of missing important clues that can lead to a correct diagnosis of AMI, particularly when the patient presents in an atypical fashion.21,23
PAs and other health care providers must be aware of patients who are prone to presenting with AMI in an atypical fashion. Patients from certain groups who tend to have symptom complexes falling outside the classic textbook description are at greater risk for a delayed or missed diagnosis of AMI. Because PAs are the first health care providers to see or evaluate these patients in the primary care or ED setting, they must maintain a heightened index of suspicion for those patients who fall outside the normal range and beyond the typical or “classic” algorithm.
Patients more likely to present in an atypical fashion while experiencing an AMI include individuals from different cultural/ethnic backgrounds; patients who have concurrent diseases, such as diabetes and CHF; and elderly patients. Some patient groups in particular are more likely to experience AMI without symptoms of chest pain. Communication and close attention to the patient's story play a critical role in identifying information pointing to an accurate diagnosis. Consideration must be given to the patient's age and cultural background to increase the likelihood of appropriate management, especially when AMI is among the diagnostic possibilities. Recognizing the influence of gender and the concerns associated with frequent visits can raise diagnostic acuity in the ED.
Practitioners should work to eliminate barriers to appropriate care by improving their culturally accurate communication skills and by forming effective relationships with patients even in the emergent settings where AMI is being considered. Actively listening to patients, asking openended questions, and treating each patient as an individual can lead to improved outcomes and patient trust. When the focus is on diagnosing AMI and identifying patients who need appropriate diagnostic evaluation, such actions can save lives.
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EARN CATEGORY I CME CREDIT by reading this article and the article beginning on page 40 and successfully completing the posttest on page 45. Successful completion is defined as a cumulative score of at least 70% correct. This material has been reviewed and is approved for 1 hour of clinical Category I (Preapproved) CME credit by the AAPA. The term of approval is for 1 year from the publication date of April 2013.