Inappropriate Sinus Tachycardia (IST) is a prevalent and debilitating condition in otherwise healthy younger patients, resulting in significant loss of quality of life, lacking effective treatment options or systematic clinical evidence to support a therapy. The primary objective of this clinical trial is to evaluate the safety and effectiveness of a hybrid sinus node sparing ablation procedure for the treatment of symptomatic drug refractory or drug intolerant IST.

Inclusion Criteria:

1. Age ≥ 18 years and ≤ 75 years at time of enrollment consent
2. Subject has a diagnosis of IST
3. Documentation of refractoriness (intolerance or failure) of a drug (e.g., rate control drugs such as beta-blockers/calcium channel blockers, ivabradine), and/or AADs
4. Subject is willing and able to provide written informed consent

Exclusion Criteria:

1. Subjects on whom cardiac surgery or single lung ventilation cannot be performed
2. Subjects with indication for or existing ICDs/Pacemakers
3. Presence of channelopathies
4. Previous cardio-thoracic surgery
5. Left Ventricular Ejection Fraction (LVEF) < 50%
6. Body Mass Index (BMI) ≥ 35
7. Presence of supraventricular or ventricular tachycardia
8. Presence of Postural Orthostatic Sinus Tachycardia (POTS)
9. Presence of congenital heart disease
10. History suggestive of secondary cause of tachycardia such as pheochromocytoma, anemia, thyrotoxicosis, chronic fever of unknown origin, COPD, long-term bronchodilators use, severe asthma or carcinoid syndrome
11. Subjects who have had a previous catheter ablation in the right atrium for IST or other disorders
12. Life expectancy < 24 months
13. Pregnant or planning to become pregnant during trial
14. Subjects with substance abuse
15. Subjects with previous weight loss surgery
16. Subject is unwilling and/or unable to return for scheduled follow-up visits
17. Current participation in another clinical investigation of a medical device or a drug, or recent participation in such a trial that may interfere with trial results
18. Not competent to legally represent him or herself (e.g., requires a guardian or caretaker as a legal representative) and;
19. Presence of other anatomic or comorbid conditions, or other medical, social, or psychological conditions that, in the investigator's opinion, could limit the subject's ability to participate in the clinical investigation or to comply with follow-up requirements, or impact the scientific soundness of the clinical investigation results