ECG challenge: a Kangaroo pitfall.

An apparently irregular rhythm was observed on bedside monitoring in a 32-week preterm infant receiving high-flow nasal cannula support during kangaroo care. The single‑lead ECG tracing demonstrated alternating QRS morphologies, initially raising concern for neonatal arrhythmia. Closer inspection revealed two independent rhythms with different cycle lengths, one representing incomplete monitor detection of the infant's underlying sinus rhythm and the other representing a second rhythm with distinct morphology. After repositioning the infant and adjusting the respiratory interface, the abnormal complexes disappeared and the heart rate increased. The tracing illustrates an important pitfall in neonatal ECG interpretation, where maternal cardiac signals may be detected by neonatal monitoring electrodes during skin-to-skin contact, mimicking arrhythmia.