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Probability diagnosis


Premature beats (ectopics)—atrial and ventricular

Sinus tachycardia, e.g. fever, exercise

Supraventricular tachycardia

Drugs (e.g. stimulants)

Serious disorders not to be missed

Myocardial infarction/angina


  • atrial fibrillation or flutter

  • ventricular tachycardia

  • bradycardia/heart block

  • sick sinus syndrome

  • torsade de pointes

Long QT syndrome

Wolff–Parkinson–White (WPW) syndrome

Electrolyte disturbances:

  • hypokalaemia

  • hypomagnesaemia

  • hypoglycaemia (type 1 diabetes)

Pitfalls (often missed)




Drugs (e.g. caffeine, cocaine)

Mitral valve disease

Aortic incompetence



  • tick bites (T1–5)

  • phaeochromocytoma

Masquerades checklist


Diabetes (indirect)

Drugs (see list)


Thyroid disorder, hyperthyroidism

Spinal dysfunction

Is the patient trying to tell me something?

Quite likely. Consider cardiac neurosis, anxiety.

Key history

Ask the patient to describe the onset and offset of the palpitations, the duration of each episode and any associated features. Then ask the patient to tap out on the desk the rhythm and rate of the heartbeat experienced during the ‘attack’. If the patient is unable to do this, tap out the cadence of the various arrhythmias to find a matching beat.

   An irregular tapping ‘all over the place’ suggests atrial fibrillation, while an isolated thump or jump followed by a definite pause on a background of a regular pattern indicates premature beats (ectopics), usually ventricular.

   Take a past history and family history including caffeine intake, smoking, alcohol, social drugs such as marijuana or cocaine, and prescribed drugs (β blockers, antipsychotics, antidepressants, thyroxine, digoxin, nifedipine, sympathomimetic).

Key examination

  • The ideal time to examine the patient is during the palpitations. If not, the examination is usually normal

  • The cardiovascular examination should assess the pulse rate, rhythm, volume and character

  • The general examination should investigate features suggestive of anaemia, anxiety, tremors, dyspnoea and thyroid disease

  • Look for evidence of mitral valve prolapse

Key investigations

A checklist includes:

  • FBE

  • TFTs

  • serum glucose

  • urea, electrolytes and magnesium

  • ECG

  • cardiac enzymes

  • echocardiography

  • Holter monitoring.

Diagnostic tips

  • A relatively non-specific symptom.

  • Consider hyperthyroidism as a cause of atrial fibrillation or sinus tachycardia even if the clinical manifestations are not apparent.

  • Arrhythmia of sudden onset suggests paroxysmal supraventricular tachycardia (PSVT), atrial flutter/fibrillation or ventricular tachycardia.

  • Common triggers for premature beats ...

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