In England and Wales, myocardial ischaemia (also known as ischaemic heart disease) was the number one cause of death in men in 2022, with 38 730 deaths, accounting for 13.3% of all male deaths. For women, dementia and Alzheimer's was the number one cause that year, accounting for 15% of female death (Office for National Statistics (ONS), 2022). Myocardial ischaemia is also the most common cause of cardiac chest pain.
Of course, there are many causes of chest pain, including non-cardiac and cardiac causes. Non-cardiac chest pain may be caused by gastrointestinal causes such as gastro-oesophageal reflux disorder (GORD) or gallbladder disease; respiratory causes such as a pulmonary embolus (blood clot in the lungs) or a chest infection, i.e. pneumonia; or musculoskeletal causes such as an inflammation of the costochondrial muscles (i.e. costochondritis) or physical trauma or degenerative changes (Paine, 2024). Such non-cardiac causes would need to be ruled out before a confident cardiac diagnosis can be made. This can be done by considering history of chest pain; presence of cardiovascular risk factors; history of myocardial ischaemia and any prior treatment; and past investigations for chest pain (National Institute for Health and Care Excellence (NICE), 2010).
In addition to the most common cause of cardiac chest pain, cardiac pain or discomfort can also be caused by moderate-to-severe aortic stenosis, spontaneous coronary artery dissection (SCAD), pericarditis, myocarditis, aortic dissection and severe valve disease – all of which are considered atypical cardiac chest pain presentations (Paine, 2024). This article will focus on cardiac chest pain caused by myocardial ischaemia, and appropriate assessment and referral for prescribers.
Chest pain caused by myocardial ischaemia
There are two broad stages of myocardial ischaemia: the first being stable angina; and the second being acute coronary syndromes, which include unstable angina and myocardial infarction (Paine, 2024).
Stable angina
Stable angina occurs as a result of physical exertion or emotional stress (NICE, 2011). Angina is described as pain or, perhaps more commonly, discomfort, heaviness, tightness or pressure, that is constricting and that tends to occur in the front of the chest (although it may radiate to the neck, shoulders, jaws or arms) (NICE, 2011; Paine, 2024). It is the main symptom of myocardial ischaemia and results from restricted blood flow and thus oxygen delivery to the heart, caused by atherosclerotic plaque in coronary artery disease (NICE, 2011).
Risk factors associated with coronary plaque formation including smoking, high low-density lipoprotein, hypertension, genetics, diabetes and obesity (Paine, 2024).
Acute coronary syndromes
Anyone with a suspected acute coronary syndrome should be referred to hospital as an emergency as this usually points to a more severe underlying issue (NICE, 2010). Assessment for the presence of the following symptoms may indicate whether a patient has an acute coronary syndrome (NICE, 2010):
- Chest pain or pain in the arms, back or jaw lasting longer than 15 minutes
- Chest pain that is associated with nausea and vomiting, marked sweating, breathlessness or a combination of these in particular
- Chest pain associated with haemodynamic instability
- New onset chest pain or an abrupt deterioration in previously stable angina, where chest pain occurs frequently, where episodes are recurrent with little or no exertion, and where episodes last longer than 15 minutes.
Angina is described as pain or, perhaps more commonly, discomfort, heaviness, tightness or pressure, that is constricting and that tends to occur in the front of the chest
Investigations for assessment
A person's risk of angina can be assessed using the QRISK3 score, which uses personal and clinical information to estimate their 10-year-risk of cardiovascular disease (Paine, 2024). If less than two of the following features is present, a diagnosis of stable or typical angina is inappropriate (Paine, 2024):
- Constricting discomfort in the front of the chest, or in neck, shoulders, jaw or arm
- Precipitated by physical exertion
- Relieved by rest or the administration of glyceryl trinitrate (GTN) within about 5 minutes.
There are other signs that indicate that a person's chest pain is not angina. For example, if pain is worse on inspiration, palpation or eating, or if it is relieved or provoked by movement of the upper body, these features are not characteristic of stable angina (Paine, 2024). Equally, pain is not constant in angina.
Another way to methodically assess the discomfort, is with the SOCRATES (Site; Onset; Character; Radiation; Alleviation; Time; Exacerbation; Severity) mnemonic tool. While the way a person describes their discomfort can vary, there are common sites where this discomfort occurs that usually remain the same. Using the SOCRATES tool as described by Paine (2024), left-sided, bilateral or central discomfort is predictive of anginal chest pain; whereas chest pain that is unilaterally right-sided is highly unlikely to be cardiac. Onset is usually gradual and with exertion. Character is described as heavy, crushing, tight, constricting, and sometimes but less often, burning. Women tend to describe more indigestion-like symptoms, which clinicians should be aware of. The pain may radiate to the left side or down both sides, or even to left arm, jaw, lower teeth or just a tooth, and only on exertion.
Angina may also be associated with breathlessness, sweating and belching. In the case of angina, discomfort should be relieved within 15 minutes or less. If more prolonged than this, it may be worsening angina or may be a different cause of chest pain. As mentioned, constant pain is not indicative of angina. In terms of exacerbating factors, angina is provoked by exertion and worsened by continuing this level of exertion.
Effective questioning of the patient experiencing the chest pain can also not be underestimated (Paine, 2024). For example, a recent study, which highlights that chest pain misinterpretation is leading cause of prehospital delay in acute coronary syndromes, posed the following questions to patients whose primary complaint was chest pain:
- Did the chest pain occur at the left/middle chest? (right-side chest pain is highly unlikely to be of cardiac origin)
- Did the chest pain radiate to the back?
- Was the chest pain provoked by activity and relieved by rest?
- Was the chest pain provoked by food indigestion, positional changes or breathing?
The authors found these questions effective for ruling out acute coronary syndrome with high predictive value (Lukitasari et al, 2023). Use of effective questioning together with establishing vital signs (such as blood pressure, oxygen levels, heart rate, electrocardiogram) can help with decision-making and appropriate referral where myocardial ischaemia is suspected (Paine, 2024).
Red flags and appropriate onward referral
One of the reasons it is so important to determine the cause of chest pain is to establish whether the patient requires emergency help. Red flags for angina that may indicate instability include the following (NICE, 2010; Paine, 2024):
- Newly occurring at rest
- Not relieved by rest or GTN within 15 minutes
- Increasing in frequency or occurring with less provocation
- Associated with nausea and vomiting, marked sweating, cool peripheries, breathlessness, or particularly a combination of all of these.
If a patient has suspected cardiac pain, which occurs only on exertion and with no red flags, they can be referred to the local rapid access chest pain clinic (RACPC) using the local pathway, with secondary prevention considered such as asprin, lipid-lowering therapy and GTN (Paine, 2024).
If the chest pain occurs at both rest and exertion, even if prolonged and severe, but without the presence of red flags, they can be told to attend sameday emergency care (Paine, 2024). However, whether occurring at rest and on exertion, and/or if prolonged and severe, with the presence of any red flags, 999 should be contacted stating a suspected myocardial infarction (Paine, 2024).