<P> Blood tests commonly performed in people with palpitations are: </P> <Ul> <Li> thyroid function tests (TFTs) - an overactive thyroid increases the risk of AVNRT </Li> <Li> electrolytes - disturbances in potassium, calcium and magnesium may predispose to AVNRT </Li> <Li> cardiac markers - if there is a concern that myocardial infarction (heart attack) has occurred either as a cause or as a result of the AVNRT; this is usually only the case if the patient has experienced chest pain </Li> </Ul> <Li> thyroid function tests (TFTs) - an overactive thyroid increases the risk of AVNRT </Li> <Li> electrolytes - disturbances in potassium, calcium and magnesium may predispose to AVNRT </Li>

In av node reentry (avnrt) a short circuit around the av node will often result in