Sphere-360 and Affera system for treating paroxysmal atrial fibrillation

Horizon 360 Protocol for the Treatment of Paroxysmal Atrial Fibrillation With the Prospective, Single Arm, Unblinded Pre-market Clinical Study to Evaluate the Safety and Effectiveness of the Sphere-360 Catheter and Affera Mapping and Ablation System for Treating Paroxysmal Atrial Fibrillation (PAF)

This trial tests the Sphere-360 pulsed field ablation catheter with the Affera mapping and ablation system in adults with recurrent symptomatic paroxysmal atrial fibrillation to see if it safely isolates the pulmonary veins and reduces AF episodes.

Quick facts

• Phase: NA
• Study type: Interventional
• Enrollment: 300 (estimated)
• Ages: 18 Years to 80 Years
• Sex: All
• Sponsor: Medtronic Cardiac Ablation Solutions (industry)
• Locations: 12 sites (Jonesboro, Arkansas and 11 other locations)
• Trial ID: NCT07308847 on ClinicalTrials.gov

What this trial studies

This is a prospective, single-arm, pre-market study enrolling up to 300 adults with recurrent symptomatic paroxysmal AF at up to 26 U.S. sites. Participants will undergo pulmonary vein isolation using the Sphere-360 pulsed field ablation catheter guided by the Affera mapping and ablation system, with predefined safety and performance endpoints tracked during follow-up. No single site may enroll more than 15% of subjects, and eligibility excludes persistent AF, very large left atrial size, and other standard contraindications. The study will characterize acute procedural success, complications, and arrhythmia recurrence rates.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18–80 with recurrent symptomatic paroxysmal AF (at least two symptomatic episodes in the prior six months and one ECG-documented episode in the prior 12 months) who can complete baseline and follow-up visits.

Not a fit: Patients with persistent AF (continuous episodes >7 days), a left atrial diameter >5.0 cm, or those who had three or more cardioversions in the past year are unlikely to benefit from participation.

Why it matters

Potential benefit: If successful, the device could offer a more selective, faster ablation option that reduces collateral tissue injury and lowers AF recurrence.

How similar studies have performed: Pulsed field ablation has shown promising pulmonary vein isolation results and favorable safety profiles in recent studies, but clinical data specific to the Sphere-360/Affera system remain limited.

Eligibility criteria

Inclusion Criteria:

1. A diagnosis of recurrent symptomatic PAF, which is defined as continuous AF episode lasting longer than 30 seconds but terminates spontaneously or with intervention within 7 days of onset, documented by the following:

   1. a physician's note indicating at least 2 symptomatic PAF episodes occurring within 6 months prior to enrollment; and
   2. at least 1 electrocardiographically documented episode within 12 months prior to enrollment
2. Adults who are ≥18 and ≤80 years of age on the day of enrollment.
3. Willing and able to comply with all baseline and follow-up evaluations for the full length of the study.

Exclusion Criteria:

1. Continuous AF lasting more than 7 days. This includes persistent atrial fibrillation (PsAF) (both early or long-standing) by diagnosis or continuous duration \> 7 days
2. AF that required three (3) or more distinct cardioversions in the preceding 12 months.
3. LA anteroposterior \> 5.0 cm (by MRI, CT, or TTE)
4. Any of the following procedures, implants, or conditions at baseline: prior left atrial catheter or surgical ablation, prior left atrial percutaneous interventions including left atrial appendage occlusion, and septal closure devices
5. Planned LAA closure procedure 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
6. Patient who is not on oral anticoagulation therapy for at least 3 weeks prior to the ablation procedure
7. 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)
8. Presence of any pulmonary vein stents
9. Known pre-existing pulmonary vein stenosis
10. Pre-existing hemidiaphragmatic paralysis
11. Prior valvular (surgical or percutaneous) procedure including prosthetic, bioprosthetic, valve replacement, valve repair or valvuloplasty, and any prior atriotomy
12. Moderate to severe aortic or mitral valve stenosis
13. Moderate to severe mitral regurgitation (i.e., 3+ or 4+ MR)
14. Any cardiac surgery, myocardial infarction, PCI / PTCA or coronary artery stenting which occurred during the 3-month interval preceding the consent date
15. Unstable angina
16. NYHA Class III or IV congestive heart failure or documented left ventricular ejection fraction (LVEF) less than or equal to 40% measure by acceptable cardiac testing (e.g. TTE), or planned transplant or left ventricular assist device (LVAD)
17. Severe lung disease, primary pulmonary hypertension, or any lung disease with abnormal blood gases or requiring supplemental oxygen
18. Rheumatic heart disease
19. Severe thrombocytosis, thrombocytopenia, or any bleeding or clotting disorder
20. Contraindication to or unwillingness to use systemic anticoagulation
21. Documented left atrial thrombus on imaging
22. Active systemic infection or sepsis
23. Hypertrophic cardiomyopathy
24. Known reversible causes of AF, including but not limited to uncontrolled hyperthyroidism, severe untreated obstructive sleep apnea, and acute alcohol toxicity
25. Any cerebral ischemic event (strokes or TIAs) which occurred during the 6-month interval preceding the consent date
26. Carotid stenting or endarterectomy
27. History of thromboembolic event within the past 6 months or evidence of intracardiac thrombus at the time of the procedure
28. 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
29. Patient with life expectancy that makes it unlikely 12 months of follow-up will be completed
30. Current or anticipated participation in any other clinical trial of a drug, device or biologic during the duration of the study not pre-approved by Medtronic
31. Known allergies or hypersensitivities to adhesives
32. Body mass index \> 40 kg/m2
33. Atrial myxoma
34. Significant restrictive or obstructive pulmonary disease or chronic respiratory condition.
35. 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
36. Solid organ or hematologic transplant, or currently being evaluated for an organ transplant
37. Presence of intramural thrombus, tumor, or other abnormality that precludes vascular access, catheter introduction, or manipulation
38. Known drug or alcohol dependency
39. Significant congenital anomaly or medical problem that, in the opinion of the investigator, would preclude enrollment in this study or compliance with follow-up requirements or would impact the scientific soundness of the clinical trial results.
40. Treatment with Amiodarone within the 3 months prior to enrollment
41. Amyloid heart disease (cardiac amyloidosis)

Where this trial is running

Jonesboro, Arkansas and 11 other locations

• Arrhythmia Research Group — Jonesboro, Arkansas, United States (RECRUITING)
• Northwestern University — Chicago, Illinois, United States (RECRUITING)
• Massachusetts General Hospital — Boston, Massachusetts, United States (RECRUITING)
• Southcoast Health System — Fall River, Massachusetts, United States (RECRUITING)
• The Valley Hospital — Paramus, New Jersey, United States (RECRUITING)
• Icahn School of Medicine at Mount Sinai — New York, New York, United States (RECRUITING)
• Northwell Health Lenox Hill Hospital — New York, New York, United States (RECRUITING)
• Atrium Health Wake Forest Baptist Medical Center — Winston-Salem, North Carolina, United States (RECRUITING)
• Bethesda North Hospital — Cincinnati, Ohio, United States (RECRUITING)
• The Ohio State University Wexner Medical Center — Columbus, Ohio, United States (RECRUITING)
• Texas Cardiac Arrhythmia Research Foundation — Austin, Texas, United States (RECRUITING)
• Inova Fairfax Hospital — Falls Church, Virginia, United States (RECRUITING)

Study contacts

• Principal investigator: Vivek Reddy, MD — Icahn School of Medicine at Mt Sinai
• Study coordinator: Leah Crocker

Conditions: Paroxysmal AF, Paroxysmal Atrial Fibrillation, Atrial Fibrillation, Pulsed Field Ablation