Supraventricular Tachycardia: Where to Ablate?

A 60-year-old woman with diabetes, hypertension, and hypothyroidism experienced palpitations for 7 years. Her palpitations were acute in onset and associated with rapid rates. She was seen initially in an emergency room where she was found to have a narrow complex tachycardia with a heart rate of approximately 200 beats per minute. Intravenous adenosine and b-blockers had no effect. Direct current cardioversion was performed to terminate tachycardia. She was subsequently able to terminate her palpitations with vagal maneuvers. She underwent an electrophysiology study during which no arrhythmias could be provoked, although there was evidence of dual atrioventricular (AV) nodal function. She was referred for repeat electrophysiology study with possible ablation.