Supraventricular Arrhythmias: An Electrophysiology Primer

Carol Chen-Scarabelli, MSN, APRN, BC, CCRN

Disclosures

Prog Cardiovasc Nurs. 2005;20(1):24-31. 

In This Article

Diagnosis

A history of symptoms related to the arrhythmia is essential and should include the presence and pattern of palpitations (regular or irregular), and whether the arrhythmia has a gradual or abrupt onset and termination.[14] The diagnosis is aided by the history, and whether or not the arrhythmia can be terminated by vagal maneuvers. Regular, paroxysmal palpitations with sudden onset and offset, with termination by vagal maneuvers, may be due to AVRT or AVNRT, whereas irregular palpitations may be due to AF or multifocal atrial tachycardia.[14]

Diagnosis of many of these arrhythmias can be made by documentation on a 12-lead electrocardiogram (ECG) ( Table IV ). A resting 12-lead ECG with evidence of preexcitation and a history of regular paroxysmal palpitations is suggestive of AVRT, whereas preexcitation with a history of irregular paroxysmal palpitations is more likely to be AF.[14] This latter group of patients require immediate evaluation by an electrophysiologist since they are at increased risk of sudden death as a result of atrial fibrillation with rapid ventricular response (caused by an accessory pathway with rapid repetitive conduction to the ventricles) deteriorating into ventricular fibrillation.[14] In addition, narrow QRS-complex tachycardia should be differentiated from wide QRS-complex tachycardia on ECG for diagnostic and treatment purposes.[14]

Since many of these arrhythmias are paroxysmal in nature, with a quick onset and offset, event monitors such as loop recorders may be needed to capture brief and/or infrequent episodes. Twenty-four-hour Holter monitors may be used if the episodes are frequent. Laboratory tests are done to rule out electrolyte imbalances, drug toxicity, and thyroid disorders as possible causes.

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