Heart Palpitations in London: When to Get an ECG and When It Is Urgent
A flutter, skipped beat or sudden racing heart can feel alarming. Many palpitations are harmless, but the useful question is not simply whether you can feel your heartbeat. It is whether the symptom comes with fainting, chest pain or breathlessness, and whether a recording can show the rhythm while it happens. A GP can take the history, examine you and arrange an ECG when indicated.
When should I seek urgent help?
Call 999 if palpitations come with chest pain, severe breathlessness or fainting. If the symptoms have stopped but you fainted, felt close to fainting or had chest discomfort, seek urgent same-day medical advice rather than waiting for a routine appointment. New symptoms during exercise, a known heart condition or a family history of sudden cardiac death also need prompt assessment. These are not symptoms to diagnose from a smartwatch alone.
What can cause a racing or irregular heartbeat?
Stress, poor sleep, caffeine, alcohol, nicotine and some medicines can trigger palpitations. They can also reflect an irregular rhythm, an overactive thyroid, anaemia or another condition. Describe whether the heartbeat feels fast, irregular or like an occasional extra beat, how long it lasts, what you were doing, and whether you felt dizzy or short of breath. Bring a list of medicines and supplements, including decongestants. The pattern helps a doctor choose the right next test; it does not replace one.
Do I need an ECG?
A 12-lead ECG records the electrical activity of your heart for a few seconds and may show an abnormal rhythm or clues to another heart problem. A normal tracing between episodes does not prove that nothing happened. If episodes are intermittent, the clinician may arrange an ambulatory monitor that records over a longer period, chosen according to how often symptoms occur. Blood tests may be useful when the history points to thyroid disease, anaemia or an electrolyte problem. An echocardiogram or cardiology assessment is not automatic for every palpitation; it depends on the findings.
What should I do before the appointment?
Note the start and finish time, pulse if you can measure it, any wearable recording, associated symptoms and possible triggers. Do not stop a prescribed medicine on your own. Cut back on obvious triggers if safe, but do not let a change in caffeine intake delay assessment of warning signs. If the symptoms are happening now and you feel unwell, seek urgent help rather than trying to collect more data.
A practical route in London
At The Online GP, a doctor can assess new or recurring palpitations and decide whether an ECG, blood tests, rhythm monitoring or specialist care is appropriate. A private GP consultation is advertised from £59; tests and follow-up can cost extra, so ask for the total before booking. This is not a substitute for emergency care. To discuss a non-emergency appointment, call +44 20 3951 3429 or email team@thewellnesslondon.com. See the clinic's broader heart-screening guide at https://www.theonlinegp.com/blog/heart-health-screening-london-2026-ecg-echocardiogram-and-cardiac-mot-complete-guide.
Frequently asked questions
Can anxiety cause palpitations? Yes, but a new symptom should not be labelled anxiety without considering the history and warning signs.
Will a normal ECG rule out an irregular rhythm? Not if the episode was absent during the recording. Ask whether longer monitoring fits the pattern.
Should I use an Apple Watch reading? Bring it if you have one. It may help document timing or rhythm, but a clinician still needs to interpret it in context.
Sources: NHS, Heart palpitations, https://www.nhs.uk/conditions/heart-palpitations/ ; NICE Clinical Knowledge Summary, Palpitations: assessment, https://cks.nice.org.uk/topics/palpitations/diagnosis/assessment/ . This article is general information, not a diagnosis. Written and reviewed by the clinical team at The Wellness.