Supraventricular tachycardia (SVT) is defined as an abnormally rapid heart rhythm originating above the ventricles. It usually has narrow QRS complexes (narrow complex tachycardia) but this is not always the case. Conventionally, atrial flutter and fibrillation are excluded from this group.
This is a companion discussion topic for the original article at https://patient.info/doctor/paediatric-supraventricular-tachycardia