Investigating palpitations

Palpitations are a common presenting symptom.

Possible causes include

• arrhythmias
• stress
• increased awareness of normal heart beat / extrasystoles

First-line investigations include:

• 12-lead ECG: this will only capture the heart rhythm for a few seconds and hence is likely to miss episodic arrhythmias. However, other abnormalities linked to the underlying arrhythmia (for example a prolonged QT interval or PR interval, or changes suggesting recent myocardial ischaemia) may be seen.
• thyroid function tests: thyrotoxicosis may precipitate atrial fibrillation and other arrhythmias
• urea and electrolytes: looking for disturbances such as a low potassium
• full blood count

Capturing episodic arrhythmias

First-line investigations are often normal in patients complaining of palpitations. The next step is to exclude an episode arrhythmia.

The most common investigation is Holter monitoring

• portable battery operated device
• continuously records ECG from 2-3 leads
• usually done for 24 hours but may be used for longer if symptoms are less than daily
• patients are asked to keep a diary to record any symptomatic palpitations. This can later be compared to the rhythm strip at the time of the symptoms
• at the end of the monitoring a report is generated summarising a number of parameters including heart rate, arrhythmias and changes in ECG waveform

If no abnormality is found on the Holter monitor, and symptoms continue, other options include: