'Hibernating' accessory pathway

Area of Science:

• Cardiology
• Electrophysiology
• Pediatric Cardiology

Background:

• Recurrent narrow QRS tachycardia can be caused by accessory pathways.
• Accessory pathways facilitate atrioventricular re-entry tachycardia.
• Successful ablation typically resolves tachycardia, but complex cases exist.

Observation:

• A 13-year-old boy with recurrent tachycardia initially showed a left lateral accessory pathway.
• Following ablation, a new right-sided accessory pathway emerged, causing recurrent tachycardia.
• The newly identified pathway exhibited specific refractory periods and inducible orthodromic atrioventricular re-entry tachycardia.

Findings:

• A concealed left lateral accessory pathway was initially identified and ablated.
• Post-ablation, a 'hibernating' right anterolateral accessory pathway became symptomatic.
• Electrophysiology confirmed the new pathway's characteristics and inducibility of tachycardia.
• Successful ablation of the second accessory pathway resolved the patient's symptoms.

Implications:

• This case highlights the potential for 'hibernating' accessory pathways to emerge and become symptomatic after ablation of another pathway.
• It underscores the importance of comprehensive electrophysiological evaluation in complex tachycardia cases.
• The findings contribute to understanding accessory pathway behavior and management strategies in adolescents.