AV Nodal Reentrant Tachycardia - Diagnosis

Diagnosis

If the symptoms are present while the patient is attending medical care (e.g. emergency department), an electrocardiogram (ECG/EKG) may show typical changes that confirm the diagnosis. If the palpitations are recurrent, a doctor may request a Holter monitor (24 hour or longer portable ECG) recording. Again, this will show the diagnosis if the recorder is attached at the time of the symptoms. Rarely, disabling but infrequent episodes of palpitations may require the insertion of a small microchip-based device (e.g. Reveal Plus) under the skin that continuously record heart activity, and can be read through the skin after an episode. All these ECG-based technologies also enable the distinction between AVNRT and other tachycardias such as atrial fibrillation, atrial flutter, sinus tachycardia, ventricular tachycardia and tachyarrhythmias related to Wolff-Parkinson-White syndrome, all of which may have symptoms that are similar to AVNRT.

Blood tests commonly performed in people with palpitations are:

• thyroid function tests (TFTs) - an overactive thyroid increases the risk of AVNRT
• electrolytes - disturbances in potassium, calcium and magnesium may predispose to AVNRT
• 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