A Prospective, Single Arm Study of the Hansen System for Introducing and Positioning the Thermocool Catheter in Patients With Paroxysmal Atrial Fibrillation


Rochester, Minn.

Trial status:

Open for Enrollment

Why is this study being done?

Atrial fibrillation (AF) is the most common sustained cardiac rhythm disturbance, increasing in prevalence with age. AF is often associated with structural heart disease, although a substantial proportion of patients with AF have no detectable heart disease. Hemodynamic impairment and thromboembolic events related to AF result in significant morbidity, mortality, and cost. Catheter ablation therapy is widely recognized as a useful modality for patients with fibrillation that are refractory to medical and ICD treatment, and is increasingly used earlier in treatment. Physicians specializing in Interventional Cardiology (IC) and/or Electrophysiology (EP) are often confronted by the need to precisely place and control a variety of therapeutic and non-therapeutic catheters in the cardiovascular space. A variety of shapeable and steerable sheaths and guide catheters have been developed to meet this need. These manually controlled catheters traditionally rely upon the ability of the experienced physician to apply varying amounts of curvature via pull wires of a steerable catheter. This tip curvature is then used in combination with insertion and torque to manipulate the distal tip of the catheter in a desired fashion. The manual control over the fine movements of the catheter's distal tip typically has limitations for performing complex mapping, ablation and other therapeutic procedures. Maintaining stable tissue contact at the point of ablation is important in achieving efficient heat transfer to tissues without increasing the power requirement, but micro-movement can be difficult to assess. Therefore, stable tissue contact relies on operator skill to exert forces at cardiac tissue that is constantly shifting due to cardio-respiratory movement. Robotic catheter manipulation may be one way to overcome or improve the issue of catheter stability. In minimally invasive surgery, robotic-assisted control of the surgical instruments has helped physicians perform difficult dexterous surgical tasks safely and efficaciously. Robotic remote control of catheters has recently been introduced to assist physicians in the safe, accurate placement of the distal catheter tip during percutaneous cardiac procedures. In ablative procedures it is not known whether improving catheter tip stability has a significant effect on lesion quality compared to the manual approach, but some recent publications of both animal and human studies comparing the Hansen Sensei Robotic System and Artisan guide catheter to manual delivery of the ablation catheter suggest that contact pressure conferred by the robotic system results in improved lesion delivery compared to a manual approach and that the use of robotic manipulation during ablation procedures has a event rate similar to manual manipulation. It has been the convention to deliver energy for up to 60 seconds for slow pathway modification and accessory pathways to produce irreversible tissue necrosis. One study suggested that by 30 seconds, robotic ablation appears to exceed the manual ablation signal attenuation at 60 seconds. The study confirmed that transmural lesions were produced at 30 seconds of robotic ablation. Therefore, it may be possible to use shorter ablation times or lower power settings for robotic approaches. This may in turn reduce the likelihood of complications for example, the risk of damage to contiguous structures and the risk of steam pop which is most likely to occur after 30 seconds at temperatures greater than 752 F (400 C). Subjects who satisfy the inclusion and exclusion criteria will be treated with the ThermoCool Catheter with one of the Artisan guide catheters controlled by the Sensei X Robotic Catheter System. Subjects will be treated according to the following schedule. Procedural/Post-Procedural Testing: - Echocardiogram prior to the introduction of the ThermoCool Catheter, for example, TEE, TTE, ICE, or IVUS. - Echocardiogram 5 minutes after removal of the ThermoCool Catheter, for example, TEE, TTE, ICE, or IVUS. - 12-Lead ECG prior to leaving the EP lab. Per the physician's discretion, the following may be performed: - Venogram or ICE to determine location, morphology, and dimensions of each pulmonary vein. - Routine EP study. - Cardioversion. - Phrenic nerve pacing. - Esophageal temperature probe. Pre-Discharge Testing/Medications: - 12-Lead ECG. - Serum creatinine, BUN, CBC. - Discharge medications to include antiarrhythmic, antiplatelet, and anticoagulants only. Follow-Up Procedures: After the index procedure (ablation), subjects will receive follow-up monitoring as follows. 7 Day: • A phone call will be made to the subject to inquire regarding any adverse events occurring with the first 7 days post-discharge. 30 day: Subjects will be asked to return for a follow-up visit at 30 days to evaluate/record: - NYHA classification. - Changes in medications (anti-arrhythmic, anti-platelet or anti-coagulants). - Occurrence of adverse events. - Physical examination, and - 12-Lead ECG. 90 day: Subjects will be asked to return for a follow-up visit at 90 days. - Subjects will undergo the same evaluation as at 30 days. - An event recorder for transtelephonic monitoring (TTM) will be issued to the patient to be used through day 365 (1 year) to document symptomatic recurrence of AF. As of the 90-day visit, TTM is required weekly for 8 weeks. In addition, the subject should do the TTM for any symptomatic recurrence of AF. After the weekly TTM for 8 weeks, TTM is required once a month and during any symptomatic recurrence of AF until the end of the study (365-days post-procedure). 180 day: Subjects will be asked to return for a follow-up visit at 180 days. - Subjects will undergo the same evaluation as at 30 days. - A 24-hour Holter monitor recording will be conducted. - Cardiac CT or MRI scan will be done to evaluate any pulmonary vein stenosis. TTM is required once a month and during any symptomatic recurrence of AF until the end of the study (365 days post-procedure). 365 day: Subjects will be asked to return for a follow-up visit at 365 days. - Subjects will undergo the same evaluation as at 30 days. - A 24-hour Holter monitor recording will be done, and - Possibly a cardiac CT or MRI scan will be obtained (if a subject had more than 50% narrowing of the a pulmonary vein at the 180-day follow up).

Who is eligible to participate?

Inclusion Criteria: 1. Subjects with paroxysmal atrial fibrillation who have had two or more spontaneously terminating episodes of atrial fibrillation, that last longer than 30 seconds and shorter than 7 days, in the nine months prior to enrollment. At least one episode must be documented with EKG, TTM, Holter monitor, or telemetry. 2. Failure of at least one Class I - IV anti-arrhythmic drug (AAD) for PAF as evidenced by recurrent symptomatic PAF, or intolerable side effects due to AADs. AADs are defined in Appendix B. 3. Signed informed consent. 4. Age 18 years or older 5. Able and willing to comply with all pre-, post-, and follow-up testing and requirements. Exclusion Criteria: 1. Atrial fibrillation secondary to electrolyte imbalance, thyroid disease, or reversible or non-cardiac cause. 2. Previous ablation for atrial fibrillation. 3. Atrial fibrillation episodes that last less than 7 days and are terminated by cardioversion. 4. Previous valvular cardiac surgery procedure. 5. Cardiac artery bypass graft procedure within the previous 180 days. 6. Previous septal defect repair. 7. Expecting cardiac transplantation or other cardiac surgery within the next 180 days. 8. Coronary PTCA/stenting within the previous 180 days. 9. Documented left atrial thrombus on ultrasound imaging (TEE). 10. Documented history of a thrombo-embolic event within the previous 365 days. 11. Diagnosed atrial myxoma. 12. Presence of an implanted ICD. 13. Presence of permanent pacing leads. 14. Significant restrictive, constrictive, or chronic obstructive pulmonary disease or any other disease or malfunction of the lungs or respiratory system with chronic symptoms. 15. Significant congenital anomaly or medical problem that in the opinion of the investigator would preclude enrollment in this study. 16. Women who are pregnant. 17. Acute illness or active infection at time of index procedure documented by either pain, fever, drainage, positive culture and/or leukocytosis (WBC > 11,000 mm3) for which antibiotics have been or will be prescribed. 18. Creatinine > 2.5 mg/dl (or > 221 µmol/L). 19. Unstable angina. 20. Myocardial infarction within the previous 60 days. 21. Left ventricular ejection fraction less than 40% 22. History of blood clotting or bleeding abnormalities. 23. Contraindication to anticoagulation medications. 24. Contraindication to computed tomography or magnetic resonance imaging procedures. 25. Life expectancy less than 1 year. 26. Enrollment in another investigational study. 27. Uncontrolled heart failure (NYHA class III or IV heart failure). 28. Presence of an intramural thrombus, tumor, or other abnormality that precludes catheter introduction or positioning. 29. Presence of a condition that precludes vascular access. 30. Left atrial size ≥ 50mm. 31. INR greater than 3.0 within 24 hours of procedure.

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