Overview
Palpation of the rate and rhythm of the radial pulse is a useful screening tool for the presence of cardiac arrhythmias.
Heart Rate
The heart rate is an invaluable vital sign that is commonly used as part of the assessment of a patient's haemodynamic state.
Normal Range
- 60 - 100bpm
How to Measure
- Count the number of beats over 15, 30 or 60 seconds and multiply to estimate beats per minute.
Causes of Tachycardia
Sinus Tachycardia
- Stress - physical exertion, anxiety, emotional stress, trauma, pain
- Fever
- Haemodynamic insufficiency - hypovolaemia, shock
- Anaemia
- Cardiovascular - pulmonary embolism, coronary ischaemia / infarction
- Endocrine - hypoglycaemia, thyrotoxicosis, phaeochromocytoma
- Drugs - beta agonists, anticholinergics, theophylline, caffeine, amphetamine, cocaine, alcohol
Other Rhythms
- Atrial - atrial fibrillation, atrial flutter, focal atrial tachycardia, multifocal atrial tachycardia
- Junctional - AV nodal reentrant tachycardia, AV reentrant tachycardia
- Ventricular tachycardia
Causes of Bradycardia
Sinus Bradycardia
- Sinus node disease - idiopathic degeneration, myocardial infarction, infiltration, connective tissue disease, cardiac surgery, Lyme disease, endocarditis
- Physiological - high cardiac fitness
- Autonomic - neurocardiogenic syncope, carotid sinus hypersensitivity
- Drugs - beta blockers, calcium channel blockers, digoxin, adenosine, ivabradine, clonidine, acetylcholinesterase inhibitors
- Hypothyroidism
- Hypothermia
- Hyperkalaemia
- Obstructive sleep apnoea
- Raised intracranial pressure
Other Rhythms
- Sinus node - sinus arrhythmia, sinus arrest, second or third degree sinoatrial exit block
- Atrial - atrial fibrillation with slow ventricular response, atrial flutter with variable block, trial escape rhythm
- AV node - second or third degree atrioventricular block, junctional escape rhythm
- Ventricular escape rhythm
Pulse Rhythm
How to Assess
- Feel the pulse for at least thirty seconds and determine whether the beats fall in time or are irregular.
Interpretation
- Regular: sinus rhythm
- Sinus arrhythmia: rhythmic variations in vagal tone with respiration
- Regularly irregular: regular heart rate with occasional missed or extra beatsSecond degree heart block, premature ventricular contractions
- Irregularly irregular: no clear patternAtrial fibrillation
Causes of Irregular Pulse
- Sinus arrhythmia
- Sinus arrest
- Second or third degree sinoatrial exit block
- Atrial fibrillation
- Atrial flutter with variable block
- Multifocal atrial tachycardia
- Second or third degree atrioventricular block
- Premature ventricular contractions
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