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A fit, well, asymptomatic 6-year-old girl was referred to clinic for a murmur. Her ECG is shown in figure 1.
Using the ECG checklist, which categories highlight possible concerns?
Rate, rhythm and PR interval
The median heart rate for a 6-year-old girl is 89 bpm (range 68–115 bpm (2nd–98th centile)).1 Here, the ventricular rate is 5–6 large squares (50-60 bpm), signifying bradycardia. The atrial rate is faster (three large squares, 100 bpm). Some P waves are obscured within T waves or QRS complexes. The P waves are not related in the normal way to the QRS complexes. Therefore, the PR interval cannot be calculated.
What does the ECG show?
Complete heart block (CHB)
The atrial and ventricular rates are different, with a complete lack of relationship (dissociation) between atrial and ventricular depolarisation. In this case, the escape rhythm originates from the His Bundle resulting in …
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
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