Diagnosis of AV Nodal Blocks

Diagnosing an atrioventricular block and identifying its degree is quite simple by using ECG and cardiac monitoring. However, the most important part is to find out the underlying cause. Therefore the following series of tests should be made:

• Serum electrolytes, magnesium, and calcium levels should be evaluated to exclude or confirm metabolic imbalance.
• Hyperkalemia can be the cause of renal insufficiency.
• If the patient is taking digoxin, then digoxin levels should be obtained. Similarly, if the patient is taking any other drugs which can result in AV block, their concentration within the bloodstream should be identified.
• If there is a suspicion that the patient has myocardial ischemia, then cardiac biomarker testing should be performed.
• If myocarditis is suspected, Lyme titers, enterovirus PCR, adenovirus PCR, HIV serologies, and Chagas titers should be identified.
• Thyroid function should be studied in order to exclude problems with thyroid gland.

Imaging techniques, including transthoracic echocardiography, can be used to diagnose valvular disease or cardiomyopathy which can be behind AV block. This technique can also be used to evaluate ventricular function. This information can then be used to decide whether the person should be implanted with a pacemaker or a defibrillator.