Paroxysmal AV block Laboratory Findings and Stimulation tests

Overview

Adenosine Plasma levels, adenosine triphosphate stimulation tests and lab values related to potential reversible causes of AV block such as a thyroid profile, electrolyte values,etc are important laboratory investigations.

Laboratory Investigations and stimulation tests

• Adenosine plasma levels (APL) and Adneosine Triphosphate (ATP)stimulation tests are tests of value in extrinsic idiopathic paroxysmal 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)".

2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: Recommendation for Laboratory Testing

Recommendation for Laboratory Testing

"1. In patients with bradycardia, laboratory tests (eg, thyroid function tests, Lyme titer, potassium, pH) based on clinical suspicion for a potential underlying cause are reasonable (Level of Evidence: C-LD) "