They said her blood work was normal and so the electrolytes I presume were also normal. It appears it is going into the fainting differential diagnosis as other possibilities were ruled out in the ER.
"The initial evaluation may diagnose up to 50% of patients and allows immediate short-term risk stratification. Laboratory testing and neuroimaging have a low diagnostic yield and should be ordered only if clinically indicated. Several comparable clinical decision rules can be used to assess the short-term risk of death and the need for hospital admission. Low-risk patients with a single episode of syncope can often be reassured with no further investigation. High-risk patients with cardiovascular or structural heart disease, history concerning for arrhythmia, abnormal electrocardiographic findings, or severe comorbidities should be admitted to the hospital for further evaluation. In cases of unexplained syncope, provocative testing and prolonged electrocardiographic monitoring strategies can be diagnostic. The treatment of neurally mediated and orthostatic hypotension syncope is largely supportive, although severe cases may require pharmacotherapy. Cardiac syncope may require cardiac device placement or ablation."
https://www.aafp.org/pubs/afp/issues...t%20evaluation.
The referral to the cardiologist was made.