[Inappropriate sinus tachycardia - non-contact mapping and ablation]

Area of Science:

• Cardiology
• Electrophysiology
• Medical Devices

Background:

• Inappropriate sinus tachycardia (IST) can be refractory to conventional pharmacotherapy, necessitating alternative treatment strategies.
• Sinus node modification/ablation is an option for managing complex IST cases.
• Non-contact mapping systems, such as EnSite Array, aid in precise ablation targeting.

Observation:

• Two female patients (28 and 45 years old) with pharmacotherapy-refractory IST underwent sinus node modification using non-contact mapping.
• Ablation proximity to the phrenic nerve required constant monitoring via superior vena cava pacing.
• One patient had a successful single ablation session.

Findings:

• The second patient experienced recurrence of IST two days post-cryoablation and again three weeks post-irrigated radiofrequency ablation.
• Phrenic nerve function monitoring was crucial during ablation procedures due to proximity.
• Non-contact mapping facilitated the sinus node modification procedure in both cases.

Implications:

• Sinus node modification can be effective for IST, but recurrence is possible.
• Careful monitoring of adjacent structures like the phrenic nerve is essential during ablation.
• Further research may explore optimal ablation strategies to minimize recurrence in complex IST cases.