Coronary artery disease is the leading cause of death in developed countries. When a patient complains of ‘chest pain’, a cardiac cause such as angina or acute myocardial infarction (MI) is considered first. There are, however, several other equally serious causes of chest pain that may go undiagnosed if they are not specifically looked for. The history is the most important aspect in the diagnosis of chest pain
“Chest radiating to left arm” – AMI pain is more likely to go to both arms or right arm contrary to traditional teaching. Swap CJ, Nagurney JT: Value and limitations of chest pain history in the evaluation of patients with suspected acute coronary syndromes. JAMA 2005; 294:2623. [Reference]
Acute Coronary Syndrome
- ACS—more likely in the presence of previous ischaemic heart disease, increasing age, diabetes, hypertension, smoking or a family history of premature ischaemic heart disease.
- Many patients have atypical pain, especially diabetics, renal patients, non-white race/ culture and the elderly and females. ACS may also present with dyspnoea, lethargy, sleep disturbance, arrhythmias or delirium (in the elderly) rather than chest pain.
- Connective tissue diseases (es SLE, but also rheumatoid arthritis) have much higher rates of ACS – the forgotten risk factor (prob best to treat similar to diabetic or renal patients)
- Reference Links: Acute Coronary Syndromes (Part I, Part II, Part III); MJA article;
- Causes of Pericarditis
- Post-viral (coxsackie, influenza, echovirus, mumps, herpes), associated with MI, cardiac surgery, radiation therapy, aortic dissection, uraemia, malignancy, TB, connective tissue disorder (SLE, RA, scleroderma or PAN).
- Post-MI pericarditis may be early or late (the latter is also known as Dressler’s syndrome)
- <20% have an identifiable cause.
- Distinguishing pericarditis from STEMI is crucial, because thrombolysis is contra-indicated in pericarditis due to the risk of hemorrhagic transformation
- The pain is sharp, retrosternal, may radiate to the back, be exacerbated by inspiration, swallowing or lying back, and is relieved by sitting up.
- A pericardial rub is best heard along the left sternal edge in expiration with the patient sitting, but may be transient. Pericarditis related to tuberculosis, uraemia or neoplastic disease is usually more insidious and pain is often mild or absent.
- ECG changes
- Commonly sinus tachycardia, widespread concave ST elevation, or PR-segment depression
- Late in the course T waves may flatten or become symmetrically inverted, sometimes permanently.
- Concomitant dysrhythmias are rare and suggest other diagnoses such as MI or myocarditis.
- Decreased voltages are suggestive of pericardial effusion and electrical alternans is a rare finding in pericardial tamponade
- CXR: Request a CXR, which is usually normal even if a pericardial effusion is present. Apparent cardiomegaly only occurs once 250 mL of pericardial fluid has accumulated
- Most patients recover within a few weeks, some go onto develop recurrent or chronic pericarditis
- Uremic pericarditis is an indication for dialysis.
- Pericardial tamponade is managed with volume loading and urgent therapeutic pericardiocentesis
- Quiz Questions: (Quiz 1)
- An inflammatory form of dilated cardiomyopathy with a high mortality rate (20% at 1 year, 50% at 5 years).
- Causes pf myocarditis:
- Chagas disease (a leading cause worldwide), viruses (enteroviruses like cox-sackie B, adenovirues, influenza A and B, mononucleosis, parainfluenza, mumps, cytomegalovirus, rubeola, rubella, rabies, lymphocytic choriomeningitis virus, hepatitis A and B, and varicella zoster), bacteria (Streptococcus, Chlamydia, Mycoplasma, Legionella, spirochaetes like Lyme disease), AIDS-related myocarditis (generally do to opportunistic infections) drugs (e.g. clozapine, cocaine, doxorubicin), immune-mediated (e.g. post-infectious, Kawasaki’s)
- Pattern: Usually flu-like illness characterised by out-of-proportion tachycardia. Chest pain, dysrhythmias or cardiac failure may or may not be present.
- ECG – tachycardia, conduction abnormalities, dysrhythmias, may mimic pericarditis or ACS.
- WBC and ESR are nonspecific.
- Viral serology
- Echocardiogrpahy – reduced left ventricular ejection fraction, global hypokinesis, and regional wall motion abnormalities
- Cardiac enzymes elevated. Normal coronary angiography.
- endocardial biopsy is the gold standard.
- Treat or remove underlying cause, provide symptomatic and supportive care, treat dysrhythmias and cardiac failure, consider extracorporeal support and cardiac assist devices pending cardiac transplantation.
- Frequently a complication of chronic hypertension, but is also associated with Marfan’s syndrome, bicuspid aortic valve or coarctation.
- There is often a strong family history despite the absence of these factors. The aorta need not be aneurysmal for dissection to occur.
- Reference Links: Aortic Dissection
- ‘Broken heart’ syndrome or stress-induce cardiomyopathy.
- More common in post-menopausal women and precipitated by severe emotional stress.
- ECG findings mimic ACS, but coronary angiography is normal and echocardiography shows ‘apical ballooning’ due to apical hypokinesis.
- May fully resolve with supportive therapy
- Reference links: What is Tako-tsubo, ECG of Tako-tsubo,
- ECG analysis (ECG Library)
- Regarding ST elevation/ depression. The ECG baseline is generally considered to be the TP segment, however some clinicians prefer to use the terminal point of the PR segment. In practice it is probably best to use the most definable, constant baseline seen on the ECG.
- Cardiac Enzymes