CARDIAC ARRHYTHMIASGeneral Medical Emergencies 612 Exclude myocardial ischaemia from ACS as a priority (see p. 44).
3 Consider other underlying precipitating factors for the arrhythmia such as
hypoxia from any cause, hypovolaemia from blood or f luid loss, electrolyte
disturbances particularly hyperkalaemia, thyroid disease, drug, alcohol or
noxious gas toxicity whether inadvertent or deliberate, septicaemia,
hy pot hermia, electrocution, or simple pain and fear.
4 Ask the patient about palpitations, ‘missed beats’, breathlessness, chest pain,
light-headedness and fatigue.
5 Measure the temperature and vital signs and attach a cardiac monitor and
pulse oximeter to the patient.
(i) Abnormal vital signs including hypotension, confusion or
associated features such as chest pain and breathlessness
necessitate urgent management.
6 Send blood for FBC, ELFTs, cardiac biomarkers, coagulation profile, thyroid
f unction and toxicolog y screen as indicated. Measure t he ABGs if in respira-
tory distress.
7 Perform an ECG. Look systematica lly at t he following:
(i) Rate: fast or slow; paroxysmal or continuous?
(ii) Rhythm: regular, regularly irregular or irregularly irregular?
(iii) P waves: present, absent and relationship to QRS complexes?
(iv) PR interval: shortened <120 ms or prolonged over 200 ms?
(v) QRS complexes: narrow or widened >120 ms?
(vi) QTc interval (corrected for rate): normal or longer than 450 ms
(470 ms in females)?
(vii) ST segment and T waves: elevated, depressed or inverted?
8 Request a CXR and look for cardiomegaly or evidence of acute pulmonary
oedema. See page 75.
MANAGEMENT
This depends on the arrhythmia, cardiovascular stability and the presence of
associated chest pain, breathlessness or confusion.
1 Give high-dose 40–60% oxygen unless there is a prior history of obstructive
airways disease, in which case give 28% oxygen. Aim for an oxygen satura-
tion over 94%.
2 Give aspirin 150–300 mg orally if there is possible or probable ACS, unless
contraindicated by known hypersensitivity.
Tip: call the senior ED doctor immediately if the patient is hypotensive
with a systolic BP <90 mmHg, is breathless, is confused or has chest
✓ pain.