An electrocardiogram (ECG, EKG) that records the electrical activity in the heart may be used to check for heart rhythm abnormalities, such as long QT syndrome, in children who have had a pallid breath holding spell.
Infants frequently have an abnormal electrocardiogram (ECG) that indicates that the right or both ventricles are enlarged, while in older children the ECG may be normal or show that the left ventricle is enlarged.
A chest x ray, electrocardiogram (ECG, EKG), echocardiogram (echo), or magnetic resonance imaging MRI) can confirm the presence of an atrial septal defect.
Examples include lumbar puncture (spinal tap), urine collection, magnetic resonance imaging (MRI), additional blood tests, or electrocardiogram (ECG).
Long QT syndrome has a medical test that can be done with ECG, but it's unclear how science plans to use this information to prevent SIDS.