Adenosine Plasma levels, adenosine triphosphate<unk><unk>  and lab values related to potential reversible causes of AV block such as a thyroid profile, electrolyte values,etc are important<unk>  investigations.
Adenosine plasma levels (APL) and Adneosine Triphosphate (ATP)stimulation<unk>  are<unk>  of value in extrinsic idiopathic<unk>  AV Block.
As previously discussed, APL levels are innately low in patients with EI AVB and therefore, on injection of ATP, AV blocks maybe reproduced.
Other lab investigations such as arterial blood gas analysis, hemoglobin, troponin or D- dimer may help with the diagnoses in appropriate clinical situations. "ESC Guidelines on Syncope (Diagnosis and Management of)".
As previously discussed, APL levels are innately low in patients with EI AVB and therefore, on injection of ATP, AV blocks maybe reproduced.
for a potential underlying cause are reasonable (Level of Evidence: C-LD) "
Paroxysmal AV block Laboratory Findings and Stimulation tests
Atrial fibrillation physical examination
Atrial flutter physical examination
First degree AV block physical examination
Paroxysmal AV block Electrophysiologic studies
Second degree AV block physical examination
Third degree AV block physical examination
Ventricular fibrillation physical examination