When a patient comes to the emergency department with chest pain, it could be anything from a life-threatening heart attack to something not serious at all like heart burn or gastritis. But neither the doctor nor patient can tell which it is until careful examination and testing is completed.
There are many different causes of chest pain including cardiac, pulmonary, vascular, gastrointestinal, and orthopedic.
Cardiac causes include ST elevation myocardial infarction, non-ST elevation myocardial infarction, and unstable angina.
When a person comes in to the ER with chest pain, he immediately receives an electrocardiogram as well as a number of blood tests and the doctor takes a history as these other procedures are going on.
The ECG is the critical step in diagnosis. If the ECG shows ST elevation in two or more contiguous leads, then the doctor diagnoses ST elevation myocardial infarction and alerts the interventional cardiologist and the cath lab for a probable emergency angioplasty/stent.
If the ECG shows other abnormalities such as ST segment depression or T wave inversion or if the ECG is completely normal, the patient may have a non-ST elevation myocardial infarction or unstable angina.
A non-ST segment elevation myocardial infarction means that the patient has suffered heart muscle damage as indicated by an elevated troponin blood test. These persons generally need to be evaluated with a coronary angiogram to see if they need to have a stent or a coronary artery bypass graft surgery.
Pts with unstable angina have no elevation of the troponin blood test and so have no evidence of permanent heart damage.
Pts with a normal ECG and normal blood tests could have unstable angina or they could have another cause of chest pain.
Other cardiac causes of chest pain include myocarditis (inflammation of the heart muscle), pericarditis (inflammation of the lining of the heart), cardiomyopathy (heart muscle damage from non-infectious causes of heart dmage).
An echocardiogram, an ultrasound heart scan, is recommended for everyone with chest pain by the European Society of Cardiology 2011 Unstable Angina guidelines.*
The echocardiogram can determine if some of the other causes of chest pain mentioned above are present. In addition, the echocardiogram can determine the pumping ability of the heart (the left ventricular ejection fraction [LVEF]. Whether the LVEF is normal or low is very important in deciding whether a patient with unstable angina who appears to be at low risk needs to have a coronary angiogram.
There is a blood test that the ECS also recommends for evaulating heart function called brain naturetic peptide (BNP). The BNP is elevated in hearts with below normal pumping function.
Pulmonary causes of chest pain in the ER include blood clot in the lung (pulmonary embolus), collapsed lung (pneumothorax), and pneumonia.
Pulmonary embolus is diagnosed by a CT lung scan for pulmonary embolus and is suggested by an elevated d-dimer blood test.
Pneumothorax and pneumonia are diagnosed by a chest x-ray.
Emergency physicians can now rapidly diagnose pneumothorax with an ultrasound scan in the emergency department.
The chest pain caused by vascular disease is aortic dissection, a life-threatening emergecy. It is diagnosed by chest CT scan. It can be suggested by an emergency department heart ultrasound that shows an ascending aortic aneurysm.
Gastrointestinal causes of chest pain include esophageal spasm, esophagitis, peptic ulcer disease, cholecystitis, and pancreatitis.
Orthopaedic causes of chest pain include muscle strain, and rib fracture.
But if the evidence points toward unstable angina then the doctor needs to decide what the next step is.
High risk unstable angina requires a coronary angiogram to see if the pt would benefit from revascularization (an angioplasty/stent or coronary artery bypass graft).
Low risk unstable angina may need a less invasive strategy like an exercise stress test.
*ESC NSTEMI-ACS guidelines available at http://www.escardio.org/guidelines-surveys/esc-guidelines/GuidelinesDocuments/Guidelines-NSTE-ACS-FT.pdf.