Vital Signs
 

Heart Rate

 
 
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Overview

  • 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.

Tachycardia

  • Heart rate greater than 100 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

Bradycardia

  • Heart rate less than 60 beats per minute.
    • 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

Postural Tachycardia

    • How To Elicit

    • Measure the heart rate with the patient lying down, and then remeasure it after the patient has been standing for one minute.
    • Interpretation

    • Postural tachycardia is present if there is a rise of >20bpm following standing.
    • Causes of Postural Tachycardia

    • Reduced intravascular volume - dehydration, haemorrhage
    • Cardiac - congestive cardiac failure, cardiomyopathy, myocarditis, constrictive pericarditis, aortic stenosis
    • Drugs - nitrates, anticholinergics, antidepressants, antihypertensives, levodopa
    • Prolonged bed rest
    • Alcohol
 
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Mathias CJ, Kimber JR. Postural Hypotension: Causes, Clinical Features, Investigation and Management. Annual Review of Medicine. 1999; 50: 317-336.
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Raj SR. Postural tachycardia syndrome (POTS). Circulation. 2013;127:2336-2342.
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