Thalassaemia (particularly if MCV is disproportionately low compared to Hb)
Anaemia of chronic disease
Chronic renal failure
Acquired sideroblastic anaemia
Antifolate drugs (phenytoin)
Patients with chronic anaemia are particularly susceptible to heart failure following transfusion. Check for existing heart conditions, such as LV ejection fraction; discuss with your seniors first and transfuse them as slowly as possible. In those with heart failure or at risk of fluid overload, it may be necessary to give furosemide orally or IV with each unit. 20–40 mg per unit will usually suffice.
Be alert to mild anaemia when checking routine blood results. Slight Hb deficits are easy to miss and can be an early sign of serious disease.
Leukoerythroblastic anaemia means there are primitive red and white cells in the peripheral circulation. The patient may need a bone marrow biopsy and investigation for occult malignancy.
Consider intra- or retroperitoneal bleeding in acute anaemia and no external evidence of haemorrhage. Look for bruising in the flanks or around the umbilicus.
Whilst abnormalities in the heart rate and rhythm are relatively common and seldom life-threatening, never be afraid to call the crash team before the patient arrests! You are not expected to diagnose and manage arrhythmias without senior advice.
When answering your bleep
Ask nursing staff for pulse, BP and temp. Give O2 if the patient is unwell, and if BP is dangerously low, consider IV fluids verbally.
ARRHYTHMIAS WHEN THE PULSE IS IRREGULAR WITH A NORMAL RATE
Atrial fibrillation (normal rate)
Wandering atrial pacemaker
Variable AV block
Measure and document both peripheral pulse rate and apex rate.
AF is associated with MI, IHD, mitral valve disease, thyroid disease, hypertension, pericarditis and other causes of a dilated atrium. Rarely, it is associated with atrial myxoma, infiltration, endocarditis and rheumatic fever. It is common following cardiac surgery, when it is usually temporary but may require short-term treatment with an anti arrhythmic like amiodarone. AF is common in patients with concurrent sepsis or electrolyte abnormalities and is more likely to resolve when these are corrected.
New-onset AF should usually be treated with anticoagulation. This may not be suitable in long-standing AF or in those with a high risk of falls, but it should always be considered, particularly in hospital where treatment-dose low molecular weight heparin (LMWH) (e.g. 1.5 mg/kg of enoxaparin) can easily be administered. To aid with decisions on anticoagulation, perform CHADSVASC and HASBLED scores on patient.
BRADYARRHYTHMIAS (ARRHYTHMIAS WITH A SLOW RATE)
Sudden stress, severe pain, post-systemic infection
Inferior MI: commonly results in first-degree AV block
AV heart block
Second-degree heart block: intermittent block with (Mobitz type 1) or without (Mobitz type 2) an elongated PR interval
Third-degree heart block: complete heart block
Drugs: amiodarone, beta blockers and calcium channel blockers, digoxin
Faulty sinus node: sick sinus syndrome, infiltration, significant inferior MI
Hypothyroidism and hypothermia
Raised intracranial pressure (ICP)
A fourth heart sound with bradycardia is common following inferior MI.
TACHYARRHYTHMIAS (ARRHYTHMIAS WITH A FAST RATE)
Sinus tachycardia (regular rhythm, normal waveform)
Hypermetabolic states, for example, fever, anxiety, hyperthyroidism, anaemia, pain
Drugs, for example, digoxin, nitrates, nicotine, sympathomimetics, theophylline, salbutamol
Shock, sepsis or hypovolaemia of any cause
Atrial fibrillation with fast ventricular response (fast AF) (rhythm will be irregular)
Atrial flutter (has regular rhythm; often 300 atrial beats per minute, with a ventricular response at 150 bpm, that is, 1:2 conduction)
Atrial tachycardia (has regular rhythm)
WPW syndrome (rhythm is regular unless AF supervenes)
Nodal (junctional) (rhythm is regular)
Broad rule of thumb in discriminating between SVT and VT:
– SVTs have narrow complexes (<120 ms) and are not necessarily associated with serious underlying heart disease.
– VTs have broad complexes (>120 ms) and indicate serious underlying heart disease.
Carotid sinus massage can cause sinus arrest or strokes, especially in the elderly, or if the patient has had a recent MI or is digitalized. Use only if urgent action is required. Vagal manoeuvres are much better (Valsalva manoeuvre).
Atrial tachycardia with heart block is commonly associated with digoxin toxicity.
Discriminating VT from SVT with bundle branch block is not easy, and you should seek senior help. If the patient is compromised, treat as VT.
Whether the patient has a VT or SVT, you need to identify and treat the underlying cause, in addition to treating the arrhythmia (Tables 8.2a and 8.2b).
Table 8.2a Managing supraventricular tachycardias. If the patient has SVT and signs of compromise (hypotension, heart failure, impaired consciousness, or a heart rate of >200 bpm), get help fast. The patient may require 100–200 J of synchronized direct current (DC) cardioversion.
Irregularly irregular pulse and no P waves on ECG
If the patient has SVT that is not AF, they may need immediate treatment, but discuss with your senior first
Regular rhythm narrow complex tachycardia
Most common type of SVT
Most SVTs respond to IV adenosine. Ensure that the patient is on a cardiac monitor and that a resus trolley is close to hand. Inject 6 mg adenosine with a flush rapidly into a large peripheral or central vein. If there is no response after 1–2 minutes, give 12 mg and then a further 12 mg if necessary. Expect facial flushing, nausea and transient breathlessness. Warn the patient of transient chest pain when you inject the adenosine
First-line treatments of acute fast AF are rate control (with metoprolol or digoxin) or rhythm control (with amiodarone or synchronized cardioversion)
Adenosine cannot be given to patients with asthma. In this case, use verapamil
Metoprolol controls the ventricular rate, but does not resolve the fibrillation. Amiodarone can restore the rhythm but requires large-vessel IV access (central line). Amiodarone requires a loading dose. Amiodarone cannot be given peripherally
Record a rhythm strip before, during and after each dose of adenosine
Once the underlying rhythm is elicited, treat accordingly
If the patient becomes compromised in anyway, shock with DC cardioversion, and then load with amiodarone
Table 8.2b Management of ventricular tachycardias.
Treat pulseless VT in the same way that you would VF – commence CPR
Sustained VT usually precipitates shock unless treated with monophasic DC cardioversion (200–360 J), so seek urgent senior help
If haemodynamically unstable, treat with synchronized DC shock, and then load with IV amiodarone
If haemodynamically stable, correct low K and Mg, and load with amiodarone.
Avoid amiodarone in patients with long QT syndrome
Investigations to consider:
U&E for K, Ca, Mg, troponin, FBC if acutely unwell
Consider in the future the need for ICDs and long-term oral amiodarone
Most labs report total serum Ca2+, of which about half is bound to albumin. If the albumin levels are low, the lab result will underestimate total Ca2+.
To calculate the corrected calcium, use the following formula:
Alternatively, ask for an ionized Ca level which need not be adjusted for albumin (a special tube is required).
On the wards, this is often spurious and an incidental finding. However, true hypercalcaemia needs to be corrected. Rarely, it requires urgent treatment.
Spurious: tourniquet left on too long or blood taken from the drip arm
Hyperparathyroidism (primary and tertiary)
Malignancy: bony metastases, myeloma and paraneoplastic syndrome
Drugs: thiazide diuretics, excessive ingestion of Ca2+-containing antacids and excessive vitamin D intake
Rarer causes: granulomatous diseases (e.g. sarcoid, TB) and endocrinopathies
Like hypercalcaemia, hypocalcaemia can be spurious and may be caused by acute hyperventilation. Hypocalcaemia is rarely an emergency, unless Ca2+ is <1.5 mmol/l (risking laryngospasm).
Spurious (low albumin as in malnutrition or chronic malabsorption, blood taken from drip arm)
Hypoparathyroidism – thyroid surgery or neck irradiation
On TPN without adequate Ca2+
Vitamin D deficiency – malabsorption, renal disease, phenytoin or phenobarbitone
Excessive ingestion of phosphate
Chest pain always requires urgent attention. Whilst angina, oesophagitis, oesophageal spasm, and musculoskeletal pain are the most common causes of chest pain, never forget pulmonary embolus in the hospital setting.
When answering your bleep
Ask the ward staff to:
Perform an ECG.
Repeat the vital signs.
If the patient has a history of IHD, prescribe sublingual glyceryl trinitrate (GTN) two puffs over the phone. Aim for sats >94%, but take care in patients with chronic obstructive pulmonary disease (COPD).
Differential diagnoses (*do not miss these!)
Angina (IHD, LVH/HOCM)
Pericarditis or myocarditis, including post-MI Dressler’s syndrome
Pancreatitis, cholecystitis and peptic ulcer disease/perforation
Rib or vertebral collapse
Pain radiating to either arm, neck or jaw suggests cardiac ischaemia. Pain radiating to the back could be a dissection. Check BP in both arms.
Sublingual GTN will often provide immediate relief of angina and is a useful diagnostic aid. It also relieves oesophageal spasm, but over a few minutes.
Oesophageal spasm or severe anxiety sometimes causes ischaemia-like changes on the ECG. Seek advice if unsure.
A tachycardic patient may also show rate-related ischaemic changes but these do not normally occur with a simple sinus tachycardia. Slowing the rate should reverse the changes.
Beware of unexpected confusion in patients. In particular, hypoxia is common but easily missed in the elderly. Never assume disorientation or dementia without first excluding serious medical causes and ascertaining the patient’s usual mental state.
When answering your bleep
Ask for a ward capillary blood glucose test (‘BM stick’ – this stands for Boehringer Mannheim, the old name for Roche Diagnostics).
Temp, BP, pulse and urine dipstick.
Pulse oximetry if available.
‘DIM TOP’ (Mike’s South African acronym!):
Drugs (especially sedatives and analgesics like opiates, anticonvulsants)
Infection (anywhere, commonly UTI and pneumonia)
Metabolic (hypoglycaemia, Na, K, Ca, liver failure, uraemia)
Nurse the patient in a moderately lit room and minimize noise. Give repeated reassurance to the patient. A well-loved family member or a familiar nurse caring for the patient is invaluable.
Consider nursing the patient on a mattress on the floor. Some hospitals have special ‘soft-walled’ beds. Bed rails and ‘hand ties’ are regarded by most nursing staff as unnecessary and potentially dangerous. Physical restraint is rarely used in the United Kingdom.
Soft music, surrounding the patient with pictures of family.
Secure NG tubes and IV lines with bandages. It is occasionally necessary to put mittens on the patient’s hands.
If you have excluded serious causes, consider short-term sedation with a benzodiazepine (lorazepam 0.5–1 mg IM, repeated after 4 hours if necessary). Use with caution in the elderly.
– Haloperidol 5–10 mg IM or PO. (Avoid in elderly patients. Haloperidol is useful in the more acute setting. Have a resus trolley to hand. You may need to wait 10–20 minutes for the drug to take effect.)
– In alcoholic patients, consider clomethiazole instead.
– ALWAYS DISCUSS WITH A SENIOR PRIOR TO USING SEDATION
You may not find any cause for the patient’s confusion. Patients may simply be disoriented from a change in environment; but make sure you exclude serious medical causes first. Clear, repeated explanation about where the patient is and why can be helpful, as is a small map showing where the toilets are and how to call for nursing assistance.
Constipation is common in hospital due to immobility, drugs and having to use a bedpan. Remember that it is a symptom and not a diagnosis. It is better to treat the cause than to blindly prescribe laxatives. Constipation is more common in the elderly and often missed. Always be alert to obstruction. Post-op ileus is common, usually resolves by itself and should never be treated with laxatives!
Poor (low roughage) diet and dehydration
Ca2+-based drugs (e.g. antacids, and calcium channel blockers)
Obstruction (acute and subacute) from any cause especially tumours, strictures, diverticulosis
Endocrine – hypothyroidism, hypercalcaemia or hypokalaemia
Spinal cord compression/lesions/trauma
By far the most common cause in hospitals is drugs (antibiotics and laxatives), but infection should always be excluded. Less common but important to consider is constipation with overflow. In all cases, the patient may need to be rehydrated.
Drugs: laxatives, broad-spectrum antibiotics, or antacids containing Mg sulphate and also cimetidine, colchicine, cytotoxic agents, digoxin or thiazide diuretics
Intestinal obstruction with overflow (neoplasm)
Faecal impaction with overflow, especially in elderly patients
Infection: Clostridium difficile or Norovirus
IBD, other causes of intra-abdominal inflammation, ischaemia, etc.
Barrier nursing is advisable until infection is ruled out.
Wash your hands with water and soap between patients.
Be wary of diarrhoea in patients on steroids. Their abdomens may be ‘silent’ despite serious intra-abdominal mischief.
If no cause is found, then consider referral to a gastroenterology specialist. There are numerous rarer causes of diarrhoea including carcinoid syndrome, VIPoma, amyloidosis, Addison’s disease, laxative abuse, lactose intolerance and tropical sprue that may need to be excluded.
Do not get too worried about interpreting ECGs during your first job. Whilst the range of potential anomalies is bewildering at first, practice really does make perfect and junior doctors are only expected to diagnose a handful of important conditions. For a more complete guide, consult Hampton’s ECG Made Easy and ECG in Practice. Whatever the ECG diagnosis, remember to treat the patient, not the ECG!
Common ECG diagnoses
Atrial fibrillation (no P waves, rate can be fast or normal)
Recent or past MI
Third-degree heart block (no relationship between P waves and QRS complexes)
Basic ECG parameters to consider
Rate: 60–90 bpm (lower in athletes).
Rhythm: irregular or regular.
Axis: normal, from −30° (aVL) to +120° (III) (some use from 0° to 90°).
P waves: present/absent before each QRS complex?
PR interval (start of P wave to start of QRS): constant? Normal interval is 120–200 ms (3–5 small squares).
QRS interval: up to 120 ms (three small squares) is ‘narrow complex’ and represents normal conduction system. If greater than this or ‘wide complex’, then the origin of the rhythm is likely to be ventricular unless there is bundle branch block. Check height of the R waves. Are Q waves present?
ST segment: isoelectric (i.e. on segment, baseline is the line between the T wave and the P wave) – raised if ST elevation (STEMI) and depressed if ST depression (ischaemia, digoxin toxicity).
T waves: upright or inverted/flipped (ischaemia) – tented in hyperkalaemia and flattened in hypokalaemia.
If the ECG is abnormal, consider each parameter systematically: