Blood tests ordered for palpitations
| Test | Why ordered |
|---|---|
| TSH (Thyroid) | Hyperthyroidism causes rapid heart rate and palpitations |
| Free T4 / T3 | Confirms hyperthyroidism if TSH is low |
| Haemoglobin (CBC) | Anaemia — heart beats faster to compensate for low oxygen |
| Potassium | Hypokalaemia triggers arrhythmias |
| Magnesium | Low magnesium — arrhythmia risk, especially with other electrolyte abnormalities |
| Calcium | Hypocalcaemia / hypercalcaemia — affect cardiac conduction |
| Blood glucose | Hypoglycaemia triggers adrenaline release, causing palpitations |
| Ferritin | Iron deficiency even without anaemia can cause palpitations |
When palpitations need emergency care
Red flag symptoms
Seek emergency care immediately for palpitations accompanied by: chest pain or pressure; shortness of breath; loss of consciousness or near-fainting (syncope); palpitations that are regular but very rapid (>150 beats per minute and not stopping); or palpitations in someone with known heart disease. These may indicate a serious arrhythmia (atrial fibrillation, ventricular tachycardia) requiring urgent ECG and treatment.
Common benign causes of palpitations
| Cause | Details |
|---|---|
| Ectopic beats (PAC/PVC) | Extra heartbeats — very common, usually harmless |
| Caffeine excess | Tea, coffee, energy drinks — stimulate heart |
| Anxiety and panic attacks | Adrenaline release — ECG and bloods usually normal |
| Exercise | Normal physiological response |
| Dehydration | Reduces blood volume — heart compensates |
| Alcohol | "Holiday heart syndrome" — atrial fibrillation after heavy drinking |
Questions to ask your doctor
- Should I have an ECG during the palpitations?
- Is my thyroid causing this?
- Do I need a Holter monitor (24-hour ECG)?
- Are my electrolytes normal?
Medical Disclaimer: For educational purposes only. Always consult a qualified healthcare professional for diagnosis and treatment.