Contemporary Management of Paroxysmal Supraventricular Tachycardia
Case History: A 15-year-old female high school student developed rapid palpitations with dizziness while playing soccer. A rescue squad obtained a rhythm strip showing a regular narrow complex tachycardia at 220 bpm. The tachycardia stops abruptly during an attempt to start an intravenous line. Her past medical history is unremarkable. Her physical exam and ECG in sinus rhythm are now normal. She is referred to an electrophysiologist to discuss therapy.
Paroxysmal supraventricular tachy- cardia (PSVT) is a common arrhythmia occurring with an incidence of 2.5 per 1000 adults.1 PSVT in the absence of structural heart disease can present at any age but most commonly first presents between ages 12 and 30. Most patients with PSVT due to atrioventricular nodal reentrant tachycardia (AVNRT) or atrioventricular reentrant tachycardia (AVRT) do not have associated structural heart disease, although exceptions (e.g., Epstein’s anomaly, familial preexcitation) do exist. Atrial tachycardias are more commonly associated with structural heart disease. In patients without structural heart disease, the physical exam during PSVT is significant mainly for rapid heart rate. Prominent jugular venous pulsations due to atrial contraction against closed AV valves may be a clue to AVNRT. History, physical exam, and an ECG constitute an appropriate initial evaluation. Further diagnostic studies are indicated only if there are signs or symptoms that suggest structural heart disease.
A 12-lead ECG during tachycardia is helpful for defining the mechanism of PSVT. In patients with brief, self-terminating episodes, an event recorder is the most effective way to obtain ECG documentation.2 Patients with panic disorder report symptoms similar to those of PSVT, and an ECG during palpitations aids in diagnosis.
Mechanisms of PSVT
Figure 1 illustrates schematically the common forms of PSVT. The AV node sits in the triangle of Koch in the floor of the right atrium. Separate pathways, characterized by their conduction …