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Dr. Alessandro Giardini
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This is one of the most common situations families bring to a paediatric cardiology appointment. Your child has had palpitations. Your GP or A&E doctor did an ECG. The result was normal. And yet the episodes are still happening, and you are still worried. Despite a normal ECG you may feel you do not have full reassurance because your child keeps having symptoms that something has not explained. That concern is entirely reasonable, and it reflects a genuine limitation of a single ECG that is worth understanding clearly.
An ECG records the electrical activity of the heart over a short period. In a typical clinical setting, that means somewhere between ten and thirty seconds of recording. The test captures what the heart is doing at that precise moment.
Palpitations in children and teenagers are almost always intermittent. They come and go. Most children are not having a palpitation episode during the brief window of an ECG recording, which means a normal result is entirely expected even when a real rhythm problem exists. A normal ECG during a symptom-free period tells you that the heart's electrical system is functioning normally right now. It does not confirm that an abnormal rhythm never occurs.
There are important exceptions. Some conditions leave permanent traces on a resting ECG regardless of symptoms. Wolff-Parkinson-White syndrome, long QT syndrome, and Brugada syndrome can all be identified on a resting ECG even between episodes. A normal ECG does meaningfully reduce the likelihood of these specific diagnoses. That is genuinely reassuring information. It does not, however, close the question of whether an intermittent arrhythmia is present.
The decision about whether to investigate further after a normal ECG depends heavily on the pattern and character of the palpitations, not the ECG result alone.
Episodes that start suddenly, feel very fast, and stop abruptly are more likely to reflect an underlying arrhythmia and justify further monitoring. Palpitations accompanied by dizziness, near-fainting, or an unusual need to stop activity also warrant a closer look, regardless of what the ECG showed. A relevant family history, including unexplained sudden death, known arrhythmia syndromes, or hypertrophic cardiomyopathy in a close relative, changes the calculus significantly.
In my consultations, I always want to understand the pattern before deciding what comes next. Brief, infrequent skipped beats in a teenager with excellent exercise tolerance, no associated symptoms, and no relevant family history often need nothing more than an ECG, reassurance, and a review of potential triggers. That is a different situation from a child with frequent, prolonged, symptom-rich episodes that have not been captured. Same normal ECG, very different path forward.
When palpitations need capturing, the next step is usually a Holter monitor or a longer-wear patch recording. This is where the real diagnostic value lies for intermittent rhythm problems.
A Holter monitor records every heartbeat continuously, typically over 24 to 48 hours, while the child goes about their usual day. Electrodes sit on the chest connected to a small recording device. The child keeps a diary, noting any symptoms and what they were doing at the time. Reviewing the recording alongside the symptom diary is where patterns emerge. An episode that the child felt, which corresponds to a documented abnormal rhythm on the recording, provides clear and actionable diagnostic information.
For children whose palpitations occur infrequently, perhaps once or twice a month, a 24-hour Holter is unlikely to capture an episode. A longer-wear adhesive patch monitor, worn for one to four weeks, increases the chances of recording during a symptomatic period. Modern patch monitors are small, waterproof, and tolerated well by children and teenagers. Some children find wearing a monitor actually reduces their anxiety, because they feel confident that if something happens it will be recorded.
An echocardiogram is also frequently performed alongside monitoring in children with unexplained palpitations. The heart's structure and function are relevant context for interpreting any rhythm findings.
A normal ECG is genuine good news. It reduces the probability of several serious conditions and provides a meaningful baseline. Reassurance based on that result is clinically appropriate in many situations.
Certainty is a different thing. No single test provides absolute certainty about every possible rhythm problem in every possible circumstance. The goal of assessment is not to reach certainty but to reach a level of clarity that allows the family to understand what is likely happening and what to do about it. Most of the time, that clarity is achievable and the picture is benign. Occasionally, further monitoring reveals something that needs attention. Either outcome is better than ongoing uncertainty.
As a paediatric cardiologist, I find that families cope best when they understand what the next step will tell them and what it will not, rather than expecting a single test to provide a definitive answer. That conversation, including what the normal ECG does and does not mean in their child's specific situation, is a central part of every consultation I have with families in this position.
Yes. SVT is intermittent. A standard ECG will appear completely normal between episodes. If SVT is suspected based on the pattern of palpitations, ambulatory monitoring to capture a symptomatic episode is needed for a definitive diagnosis.
Standard Holter monitoring runs for 24 to 48 hours. For children whose symptoms occur less frequently, patch monitors worn for one to four weeks substantially increase the likelihood of capturing an episode.
A normal ECG is genuinely reassuring, and in many cases no further investigation is needed. If palpitations are frequent, prolonged, accompanied by dizziness or near-fainting, or if there is a relevant family history, a paediatric cardiology opinion adds real value and may lead to ambulatory monitoring.
Not always. Long QT syndrome can sometimes be identified on a standard ECG, but the QTc interval needs careful measurement, and borderline values require specialist interpretation. Some genetic forms of long QT syndrome are not reliably detected on a resting ECG alone.
Multiple normal ECGs do provide meaningful cumulative reassurance. Whether further investigation is warranted depends on what the palpitations are like, whether they are accompanied by any concerning features, and the family history. A paediatric cardiologist can help decide whether ambulatory monitoring is likely to add useful information in your child's specific situation.