Chest pain - ACEM Fellowship Notes

see also: [[HEART score]], [[PE clinical prediction scores]] # Rapidly fatal causes of chest pain in ED - [[ACS]] - [[Pulmonary Embolism]] - [[Aortic dissection]] - Tamponade - Oesophageal rupture - [[Trauma/pneumothorax]] # ACS exclusion in ED > AKA the "Troponin Shuffle" > - Note that the Australian clinical [ACS guidelines](https://www.heartfoundation.org.au/for-professionals/acs-guideline) have been updated in 2025 (prev updated 2016) **Assessment in suspected ACS should:** 1. Identify people wiht acute coronary occlusion myocardial infarction (ACOMI) -- [[STEMI ECG patterns|STEMI]] and [[STEMI equivalents]] 2. Identify people with NSTEMI 3. Identify people with [[Unstable angina]] at high risk for 30-day MACE 4. Identify people with underlying CAD in whom ACS is not confirmed ![[Pasted image 20250512114446.png]] > [!caption] Probability of cardiac ischaemia based on commonly used descriptors of chest pain ## Determining risk - overall goal is to determine if patient is: - high risk (30-day MACE >50%) - intermediate risk (30-day MACE 2-22%) - negative trop likely can have outpatient follow up - low risk (30-day MACE <1%) ### History - See image above regarding history descriptors of chest pain ### ECG see: [[STEMI ECG patterns]] and [[STEMI equivalents]] Journal club summary for 2021 OMI paper: [[OMI vs STEMI journal club.pdf]] ***STEMI and STEMI-equivalents:*** ![[Pasted image 20250513094646.png]] > [!caption] ECG findings consistent with acute coronary occlusion myocardial infarction (ACOMI) from [2025 guidelines](https://www.heartfoundation.org.au/for-professionals/acs-guideline?tab=2#Initial%20ECG%20assessment) | Cardiac region | Leads with STE | Reciprocal STD | | ----------------- | ---------------------------- | -------------- | | Anterolateral | I, aVL, V3–V6 | II, III, aVF | | Anteroseptal | V1–V4 | None | | Septal | V1, V2 | None | | Inferior | II, III, aVF | I, aVL | | Right ventricular | Right-sided chest leads V3–6 | | | Posterior | Posterior leads V7–9 | V1–V3 | | Lateral | I, aVL, V5, V6 | II, III, aVF | | High lateral | I, aVL (V2) | III (II, aVF) | ***High risk ECG findings for ACS:*** > Certain ECG patterns are associated with potential progression to ACOMI. They require prompt and continuous ECG monitoring ![[Pasted image 20250513094924.png]] > [!caption] High-risk ECG findings for ACS and findings suggestive of cardiac ischaemia, from [2025 guidelines](https://www.heartfoundation.org.au/for-professionals/acs-guideline?tab=2#Initial%20ECG%20assessment) ### Special demographics | Demographic | Issues | | ---------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Women | - Often misdiagnosed with non-ischaemic CP | | Older adults | - Use uniform hs-cTn cut-offs for clinical assessment, recognising that trop concentrations ↑ with age in health individuals - This may result in fewer older adults being classified as low risk for MI - In people >65 years with comorbidities such as renal impairment, specificity of high sensitivity trop for MI is reduced | | First Nations | - Investigate all First Nations adults with suspected ACS for underlying CAD, given ↑ risk of future cardiac events - HEART score has not been well-validated in First Nations populations | | Renal impairment | - Common to have elevated trop, ∴ fewer will be classified as low risk | ## High-sensitivity troponin-based clinical decision pathways - Used in the context where the ECG is not a STEMI or [[STEMI equivalents|STEMI equivalent]] - See [[Troponin#Troponin assay cutoffs|Troponin assay cutoffs]] for the convoluted table included in the current guidelines; just use your hospital's local policy on troponin cutoffs | Option | Indication | MACE risk | | ------------------------ | ------------------------------------------------------------------------------------------------------------------------------------ | ---------------------------------- | | Single hs-cTn trop | - symptoms onset ≥ 2 hours - non-ischaemic ECG | <1% short- and long-term follow up | | 0/1 or 0/2 hour strategy | - symptom onset ≤ 2 hours - low or intermediate risk - very assay dependent; for the most part need to use a *2 hour* strategy | ≤ 2% 30 day MACE | ### HEART see [[HEART score]] ### High-STEACS ![[Pasted image 20250512064727.png]] > [!caption] High-STEACS algorithm ## Discharge planning - People with suspected ACS who do not require admission for further assessment or management can be discharged - *Low risk* people can be given advice that they have been assessed against an evidence-based approach and AMI and unstable angina are unlikely, although coronary artery disease has not been excluded and follow up with GP in accordance with the [Australian guideline for assessing and managing cardiovascular disease risk](https://www.cvdcheck.org.au/) is recommended. Give info about what to do if they have recurrent symptoms, give education on primary prevention and education services. - if low risk and symptom-free, further cardiac testing for CAD is not routinely required. assess and manage cardiovascular risk factors. - *Intermediate risk* patients should have clarity about follow up - if troponin is not elevated, "consider" outpatient investigations with non-invasive testing [guideline reference](https://www.heartfoundation.org.au/for-professionals/acs-guideline?tab=2#Further%20diagnostic%20testing%20for%20people%20with%20suspected%20ACS) > [!quote] > For people at intermediate risk, invasive angiography or non-invasive cardiac testing is recommended to refine risk stratification, identify alternative causes of chest pain and assess future risk of ACS beyond 30 days. Inpatients with elevated hs-cTn levels above the 99th percentile should undergo testing due to a 30-day cardiac event rate of 2–22%, while those with hs-cTn ≤99th percentile may consider outpatient testing within 30 days, as their event rate is <2% [16]. Non-invasive testing is not routinely recommended for low-risk individuals, as their likelihood of cardiac events over two years is minimal. General practitioner follow-up is advised for symptom resolution, treatment and assessment of long-term cardiovascular risk using Australian guidelines ([cvdcheck.org.au](https://www.cvdcheck.org.au/)) > Note here that *intermediate* risk can potentially go home (i.e. Cardiology will not want to admit them if they are trop negative). However, [[Unstable angina]] is by definition High Risk and included in the definition of ACS and in my view should certainly be admitted to hospital under cardiology in most cases besides specific patients with chronic ischaemic chest pain who frequently present. ## Non-invasive testing | Test | Overview | indication | | ---------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Anatomical testing (CTCA) | - normal CTCA (no obstructive or non-obstructive plaque) reliably excludes ACS and indicates extremely low risk of ACS for 4-5 years - identifying non-obstructive plaques can help guide preventative therapies eg statins - do NOT rely on coronary artery calcium score alone in ACS evaluation unless combined with CTCA | - no previously known CAD presenting with intermediate risk ACS | | Functional testing | - eg stress cardiac MRI, stress photon-emission CT (SPECT), exercise ECG - stress cardiac MRI and ECHO can evaluate LV function, RWMA, and valve function, and exclude myopericardits and Takotsubo | - known CAD, prior stents, or extensive coronary calcification, where CTCA interpretation may be more challenging - functional testing can help identify whether symptoms are caused by obstructive plaque and assess ischaemic burden and short-term prognosis. | | Test | Strengths | Weaknesses | Considerations for use | | ------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Exercise Stress ECG | - Cheap - available - assessment of exercise symptoms - no radiation | - ↓ accuracy compared with anatomical and stress-imaging tests - need to be able to exercise - ↑ false positive rate in females | - rarely recommended as stand-alone test in people with known CAD, inability to exercise, or significant arrhythmias - contraindicated in severe symptomatic [[Aortic stenosis]] or severe HTN | | Stress ECHO | - available - high specificity - assessment of ventricular and valve function | - ↓ sensitivity compared with CTCA and other stress-imaging tests - needs good images - needs dobutamine in people who can't exercise | - good for people with good image quality and ability to exercise - known moderate or severe valvular disease | | Stress / rest SPECT | - available - relatively high sensitivity - can assess ventricular function | - artifacts can cause non-diagnostic results and decrease accuracy compared with stress/rest PET - radiation exposure | - known CAD or high coronary artery calcification burden on chest CT - preferred over stress ECHO in people who cannot exercise or have significant exercise-induced bronchospasm | | Stress / rest PET | - high diagnostic accuracy - measures myocardial blood flow and flow reserve - assessment of ventricular function - lower radiation than SPECT | - less availability - expensive - does NOT assess exercise | - known CAD or high coronary artery calcification burden on chest CT - preferred over SPECT due to higher diagnostic accuracy and lower rate of nondiagnostic test results | | Stress cardiac MRI | - high diagnostic accuracy - accurate assessment of chamber size, ventricular and valvular f(x) - see prior infarcts and scars - measure myocardial blood flow nd flow reserve is ossible | - limited availability - expensive - no exercise assessment - take a long time to perform - often not available to pts with PPMs or ICDs - contraindicated if significant renal impairment | - known CAD and/or cardiomyopathy - elevated troponin not thought to be secondary to ACS - known moderate or severe valve disease - no significant renal dysfunction | | CTCA | - high diagnostic accuracy - does not require exercise - identifies non-obstructive coronary artery disease | - no exercise assessment - blooming artifacts from significant coronary calcificaiton present - AF and other arrhythmias may cause issue - may need beta blockers - incidentalomas | - no known CAD - absence of severe coronary calcification - prior normal, mildly abnormal, or inconclusive stress test results - no contrast allergy - low likelihood of high-quality stress testing or cannot access |