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Redo AF ablation using the Sphere-9 catheter and Affera system for recurrent paroxysmal and persistent atrial fibrillation

Conquer-AF Protocol for Redo Ablation Procedures in Recurrent Paroxysmal and Persistent Atrial Fibrillation Using the Sphere-9 Catheter and Affera Ablation System (Conquer-AF)

Not applicable Interventional Medtronic Cardiac Ablation Solutions · NCT07298473

The study will try the Sphere-9 catheter with the Affera ablation and mapping systems for adults who have symptomatic recurrent paroxysmal or persistent atrial fibrillation after one prior ablation.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment400 (estimated)
Ages18 Years and up
SexAll
SponsorMedtronic Cardiac Ablation Solutions Industry-sponsored
Locations30 sites (Birmingham, Alabama and 29 other locations)
Trial IDNCT07298473 on ClinicalTrials.gov

What this trial studies

This is a prospective, multi-center, non-randomized interventional study enrolling up to 400 adults with symptomatic recurrent paroxysmal or persistent atrial fibrillation after a single prior ablation. Each participant will undergo a redo ablation procedure using the Sphere-9 Catheter and Affera Ablation System with the Affera Mapping or Integrated Mapping System and then be followed for 12 months. Follow-up visits are scheduled at 7 days, 3 months, 6 months, and 12 months with cardiac monitoring including a 24-hour Holter at study exit. The study will collect safety and effectiveness data across up to 30 sites in the United States, Europe, and Australia.

Who should consider this trial

Good fit: Adults (≥18) with symptomatic recurrent paroxysmal or persistent AF documented after a single prior ablation procedure within the past three years and willing to comply with follow-up are the intended candidates.

Not a fit: Patients with continuous AF for 12 months or longer, left atrial size above protocol thresholds, more than one prior AF ablation, or inability to follow study procedures are unlikely to benefit from this protocol.

Why it matters

Potential benefit: If successful, this approach could reduce recurrent AF episodes and improve symptom control for patients needing a redo ablation.

How similar studies have performed: Advanced mapping and pulsed field or modern radiofrequency ablation technologies have shown promising results in prior work, but the Sphere-9 catheter used with the Affera system for redo procedures is a relatively new combination with limited prior large-scale data.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* 1\. History of a single AF ablation procedure for PAF or PsAF within 3 years prior to enrollment 2. Documented evidence of symptomatic AF, AT or AFL recurrence at least 90 days after subject's de novo ablation procedure, as demonstrated by:

  * A physicians' note indicating at least 1 symptomatic AF, AT, or AFL episode occurring within 12 months prior to the enrollment; and
  * At least 1 electrocardiographically documented episode of AF, AT, or AFL within 12 months prior to enrollment 3. Adults who are ≥18 years of age on the day of enrollment 4. Willing and able to comply with all study requirements and provide informed consent

Exclusion Criteria:

* 1\. Continuous AF lasting for 12 months or longer 2. LA anteroposterior \>55 mm (by MRI, CT, or TTE), or if LA diameter not available, non-index volume \>100 mL for PsAF subjects; OR LA anteroposterior \>50 mm (by MRI, CT, or TTE), or if LA diameter not available, non-index volume \>95 mL for PAF subjects 3. Previous left atrial percutaneous interventions including left atrial appendage occlusion and septal closure devices 4. Planned left atrial appendage (LAA) closure procedure, cardiac transplantation or implant of a permanent pacemaker, biventricular pacemaker, loop recorder/insertable cardiac monitor (ICM), or any type of implantable cardiac defibrillator (with or without biventricular pacing function) for any time during the follow-up period 5. More than 1 previous AF ablation procedure 6. Any prior surgical ablation procedure 7. Patient who is not on oral anticoagulation therapy for at least 3 weeks prior to the ablation procedure 8. Contraindication to or unwillingness to use systemic anticoagulation 9. Severe thrombocytosis, thrombocytopenia, or any bleeding or clotting disorder 10. Presence of a permanent pacemaker, biventricular pacemaker, loop recorder/insertable cardiac monitor (ICM), or any type of implantable cardiac defibrillator (with or without biventricular pacing function) 11. Presence of any pulmonary vein stents 12. Known pre-existing pulmonary vein stenosis 13. Pre-existing hemidiaphragmatic paralysis 14. Prior valvular (surgical or percutaneous) procedure including prosthetic, bioprosthetic, valve replacement, valve repair or valvuloplasty, or any prior atriotomy 15. Moderate to severe mitral valve or aortic stenosis 16. Moderate to severe mitral regurgitation (i.e., 3+ or 4+ MR) 17. Any cardiac surgery, myocardial infarction, PCI/PTCA or coronary artery stenting which occurred within the 3 months preceding the consent date 18. NYHA Class III or IV congestive heart failure 19. Documented left ventricular ejection fraction (LVEF) ≤40%, measured by acceptable cardiac testing (e.g., TTE) 20. Unstable angina 21. Severe lung disease, primary pulmonary hypertension, or any lung disease requiring supplemental oxygen 22. Rheumatic heart disease 23. Significant restrictive or obstructive pulmonary disease or chronic respiratory condition 24. Presence of left atrial thrombus on imaging 25. Active systemic infection or sepsis 26. Hypertrophic cardiomyopathy 27. Amyloid heart disease 28. Diagnosed atrial myxoma 29. Known reversible causes of AF (e.g., uncontrolled hyperthyroidism, severe untreated obstructive sleep apnea, acute alcohol toxicity or other reversible or non-cardiac cause) 30. Any cerebral ischemic event (strokes or TIAs) which occurred within the preceding 6 months of the consent date through the date of study index redo ablation procedure 31. Carotid stenting or endarterectomy 32. Thromboembolic event within the past 6 months or evidence of intracardiac thrombus at the time of the procedure 33. Body mass index \> 40 kg/m2 34. Any woman known to be pregnant or breastfeeding, or any woman of childbearing potential who is not on a reliable form of birth regulation method or abstinence\* 35. Patient with life expectancy that makes it unlikely 12 months of follow-up will be completed 36. Current or anticipated participation in any other clinical study of a drug, device or biologic during the duration of the study not pre-approved by Medtronic 37. Renal insufficiency with an estimated glomerular filtration rate (eGFR) \<30 mL/min/1.73 m2, or any history of renal failure requiring dialysis or renal transplant 38. Presence of intramural thrombus, tumor, or other abnormality that precludes vascular access, catheter introduction, or manipulation 39. Presence of an inferior vena cava (IVC) filter (e.g., Greenfield or similar) that would preclude safe transfemoral venous access, catheter passage, or sheath manipulation.

  40\. Known drug or alcohol dependency 41. Significant congenital anomaly or medical problem that would, in the opinion of the investigator, preclude enrollment, follow-up compliance, or the scientific integrity of the study

  \*Women who are of child-bearing potential must undergo a pregnancy test after consent and prior to the study index redo ablation procedure, as allowed according to local regulations

Where this trial is running

Birmingham, Alabama and 29 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Atrial FibrillationPersistent Atrial FibrillationParoxysmal Atrial FibrillationSphere-9 CatheterAffera Ablation SystemAffera Mapping SystemPulsed Field AblationRadiofrequency Ablation
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.