Recognising Tachycardia for Student Nurses
Learn how to recognise a rising heart rate, assess the patient rather than the number alone, and understand why tachycardia can be an important early sign of physiological stress or deterioration.
What is tachycardia?
Tachycardia means that the heart rate is faster than expected. In adults, a resting heart rate above 100 beats per minute is commonly described as tachycardia, although the significance depends on the individual patient and clinical context.
How fast?
A heart rate above 100 bpm is commonly used as the adult threshold for tachycardia.
What has changed?
A pulse rising from the patient's usual level may be important even before it becomes markedly elevated.
Why is it happening?
Pain, fever, dehydration, anxiety, blood loss and acute illness can all contribute to a rising heart rate.
How to assess a fast pulse
Confirm the rate
Ensure the measurement is accurate and repeat it manually where appropriate if the reading appears unexpected.
Assess the rhythm
Consider whether the pulse feels regular or irregular and report unexpected rhythm changes appropriately.
Assess pulse quality
Note whether the peripheral pulse feels strong, normal or weak within the limits of your clinical competence.
Review other observations
Look at respiratory rate, blood pressure, oxygen saturation, temperature and consciousness.
Ask about symptoms
Consider chest discomfort, palpitations, breathlessness, dizziness, pain and how the patient feels generally.
Compare the trend
Review previous observations and identify whether the heart rate is stable, improving or progressively increasing.
Why might a patient's pulse rise?
| Possible context | Other clues | Clinical thinking |
|---|---|---|
| Pain | Patient reports pain, distress or discomfort. | Pain can increase sympathetic activity and raise heart rate. |
| Fever or infection | Raised temperature, altered observations or feeling unwell. | A rising pulse can form part of the physiological response to infection. |
| Dehydration | Poor intake, fluid losses, reduced urine output or dizziness. | Reduced circulating volume can contribute to an increasing heart rate. |
| Blood loss | Known or suspected bleeding, pallor or circulatory changes. | Tachycardia may be an early compensatory response to blood loss. |
| Respiratory compromise | Breathlessness, increased respiratory rate or altered oxygenation. | A fast pulse may accompany respiratory distress or hypoxaemia. |
| Anxiety or distress | Patient appears anxious, frightened or acutely distressed. | Anxiety can increase heart rate, but physical causes still need appropriate consideration. |
Ask “why?” rather than simply recording the number
A heart rate of 110 bpm after walking may have a very different significance from a resting heart rate that has progressively risen from 78 to 110 bpm in an acutely unwell patient.
When tachycardia becomes more concerning
- The heart rate is progressively increasing.
- Blood pressure is falling.
- Capillary refill is prolonged or the skin is cool and clammy.
- Respiratory rate is increasing.
- Oxygen saturation is falling or oxygen requirements are increasing.
- The patient has new confusion, drowsiness or reduced responsiveness.
- Urine output is falling.
- There is known or suspected bleeding.
- The patient has signs of significant infection or acute illness.
The direction of travel matters
One observation provides a snapshot. Repeated observations can reveal whether the patient's physiology is moving towards recovery or deterioration.
Pulse 82 bpm
Patient comfortable with observations close to their usual baseline.
Pulse 98 bpm
Still within or near commonly encountered ranges, but noticeably higher than the patient's earlier value.
Pulse 116 bpm
The continuing upward trend should trigger assessment of the patient and the wider observation pattern.
Small changes can become important trends
Clinical deterioration does not always begin with one dramatically abnormal observation. Progressive change across several observation sets may provide the earlier warning.
Putting the observations together
Example
A patient's pulse was 84 bpm earlier in the shift. It is now 118 bpm while they are resting in bed.
They appear pale and clammy. Their blood pressure has fallen and capillary refill is prolonged.
You also learn that they have had repeated diarrhoea and poor oral intake.
The important finding is not simply the pulse of 118 bpm. It is the combined pattern of tachycardia, fluid loss and worsening circulation.
As a student nurse, recognise the deterioration, obtain accurate observations and communicate the findings promptly to the appropriate registered practitioner.
Tachycardia assessment errors to avoid
- Recording the pulse without asking why it is high. Assess the clinical context.
- Looking only at the threshold. A rising trend from baseline can matter.
- Assuming anxiety explains everything. Consider physical causes appropriately.
- Ignoring rhythm. An unexpectedly irregular pulse should be communicated.
- Ignoring other observations. Pulse becomes more meaningful when combined with BP, respiratory rate and perfusion.
- Waiting for extreme tachycardia. Earlier physiological change may already warrant assessment.
Recognise → assess → communicate → escalate
Notice the rise
Identify tachycardia or a significant increase from the patient's previous heart rate.
Look for the cause
Review symptoms, blood pressure, respiration, temperature, perfusion, fluid status and the wider clinical picture.
Describe the trend
Report the current heart rate, previous values and associated clinical changes clearly.
Recognising Hypotension for Student Nurses
Learn how to recognise low and falling blood pressure, assess associated symptoms and understand why hypotension can indicate impaired circulation and patient deterioration.
Continue to Recognising Hypotension →