The patient:  This ECG was obtained from a two-month-old girl who was a patient in the Emergency Department.  She had a fever due to a respiratory infection and was dehydrated. She was alert, active, and irritable.

The ECG:  There is a narrow-complex tachycardia at a rate of 194 bpm.  This is faster than the normal range for a two-month-old, which is about 80-160 bpm.  The intervals are all within normal range.  The frontal plane axis, at 145 degrees, is rightward, which is normal for this age. There are prominent, narrow Q waves in the inferior wall leads (II, III, and aVF) and in the left lateral leads (V4, V5, and V6).  There are no Q waves in the high lateral leads (I and aVL).  This is a normal pattern for this age group.   www.sciencedirect.com/science/article/pii/B9781416037743100280

The evaluation of this ECG must be preceded by a thorough evaluation of the patient.  SINUS TACHYCARDIA would be expected in the setting of fever, dehydration, hypoxia, pain or other discomfort. Should the rate fail to gradually return to a normal range after treatment, we would have to consider a reentrant supraventricular tachycardia. Reentrant tachycardias have a SUDDEN ONSET and SUDDEN TERMINATION.

Unfortunately, we do not have follow up on the patient.