Differentials
Unstable angina
SIGNS / SYMPTOMS
Unstable angina presents as new onset of severe angina, angina at rest or minimal activity, or recent increase in frequency or intensity of chronic angina.
INVESTIGATIONS
ECG typically shows ST depression and/or T-wave inversion for unstable angina, but can also be normal. Troponin levels should be normal.
ST-elevation myocardial infarction (STEMI)
SIGNS / SYMPTOMS
Acute MI may present as new onset of severe angina, angina at rest or minimal activity, or recent increase in frequency or intensity of chronic angina.
In a minority of people with diabetes, MI may present without symptoms.
INVESTIGATIONS
ECG changes for STEMI include ST-segment elevation, T-wave inversion, and Q-wave formation. Troponin levels are elevated in STEMI.
Non-ST-elevation myocardial infarction (NSTEMI)
SIGNS / SYMPTOMS
Acute MI may present as new onset of severe angina, angina at rest or minimal activity, or recent increase in frequency or intensity of chronic angina.
In a minority of people with diabetes, MI may present without symptoms.
INVESTIGATIONS
ECG typically shows ST depression and/or T-wave inversion for NSTEMI, but can also be normal. Troponin levels are elevated in NSTEMI.
Chronic stable angina
SIGNS / SYMPTOMS
Patients typically present with exertional chest pain relieved by rest.
INVESTIGATIONS
ECG is usually normal between episodes, but during angina episodes ST depression and/or T-wave inversion may be present. Cardiac enzymes are usually not elevated.
Congestive heart failure
SIGNS / SYMPTOMS
Symptoms of cough, shortness of breath, orthopnoea, paroxysmal nocturnal dyspnoea, or peripheral oedema.
Findings of jugular venous distension, pulmonary congestion, and S3 gallop.
INVESTIGATIONS
Diagnosis can be made clinically, but several studies may assist if diagnosis is not clear.
Chest x-ray may reveal cardiomegaly, pulmonary oedema, and cephalisation of pulmonary vasculature.
Serum brain natriuretic peptide is usually elevated.
Echo provides information about left ventricular function, differentiates systolic from diastolic dysfunction, and identifies underlying valvular or structural heart disease.
Heart failure with preserved ejection fraction
SIGNS / SYMPTOMS
Clinical syndrome of heart failure, with symptoms of pulmonary and peripheral congestion.
INVESTIGATIONS
Normal left-ventricular systolic function and increased diastolic filling pressures on echo.
Transient ischaemic attack (TIA)
SIGNS / SYMPTOMS
Sudden onset of neurological deficit. Most TIAs last between 5 and 15 minutes.
INVESTIGATIONS
Diagnosis is made by complete resolution of symptoms in <24 hours and no acute ischaemic findings on brain imaging. Acutely, non-contrast CT of the head is used to exclude intracerebral haemorrhage.
Ischaemic stroke
SIGNS / SYMPTOMS
Sudden onset of neurological deficit. Symptoms lasting ≥24 hours are classified as a stroke.
INVESTIGATIONS
CT or MRI will show ischaemic stroke. Acutely, non-contrast CT of the head is used to exclude intracerebral haemorrhage.
Haemorrhagic stroke
SIGNS / SYMPTOMS
Sudden onset of neurological deficit. Symptoms lasting ≥24 hours are classified as a stroke.
INVESTIGATIONS
Acutely, non-contrast CT of the head can show intracerebral haemorrhage.
Peripheral artery disease (PAD)
SIGNS / SYMPTOMS
Intermittent claudication: pain, ache, cramp, burning, fatigue, weakness, or numbness in the leg muscles that develops predictably with exercise, increases with progressive exercise intensity, and is relieved by rest (usually within 10 minutes).[29] Pain in buttocks and thighs suggest aorto-iliac disease, while calf muscle pain suggests femoral or popliteal artery disease. Patients with more severe disease may present with rest pain (often affecting the forefoot) or non-healing/slow-healing leg ulcers. Erectile dysfunction is also a symptom in some patients.[29]
INVESTIGATIONS
Joint American Heart Association and American College of Cardiology guidelines recommend that all patients with history or physical examination findings suggestive of PAD should have a resting ankle-brachial index (ABI), with or without ankle pulse volume recordings and/or Doppler waveforms.[29] Screening with resting ABI is also considered reasonable in patients with the following characteristics: age ≥65 years or older; age 50 to 64 years with risk factors for atherosclerosis (e.g., diabetes, smoking history, dyslipidaemia, hypertension), chronic kidney disease, or family history of PAD; age <50 years with diabetes and one additional risk factor for atherosclerosis; patients with known atherosclerotic disease in another vascular bed (e.g., coronary, carotid, subclavian, renal, mesenteric artery stenosis, or abdominal aortic aneurysm).[29] The American Diabetes Association recommends screening for PAD using ABI in asymptomatic people with diabetes who have any of the following characteristics: age ≥50 years; diabetes with duration ≥10 years; comorbid microvascular disease; clinical evidence of foot complications; or any end-organ damage from diabetes.[30] ABI results: 1.0 to 1.4 is normal; 0.91 to 0.99 is borderline; ≤0.9 is abnormal.[29]
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