Horizon 360 Protocol for the Treatment of Paroxysmal Atrial Fibrillation With the Sphere-360™ Catheter and Affera™ Mapping and Ablation System (Horizon 360) (Horizon 360)

May 20, 2026 updated by: Medtronic Cardiac Ablation Solutions

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)

The study is a prospective, single-arm, pre-market clinical study and will enroll up to 300 subjects at up to 26 sites in the United States (US) for analysis of primary objectives. No single site may contribute more than 15% of the enrollments.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

300

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • Arkansas
      • Jonesboro, Arkansas, United States, 72401
    • Florida
      • Naples, Florida, United States, 34102
        • Recruiting
        • NCH Rooney Heart Institute
        • Principal Investigator:
          • Dinesh Sharma
        • Contact:
    • Illinois
      • Chicago, Illinois, United States, 60611
        • Recruiting
        • Northwestern University
        • Principal Investigator:
          • Bradley Knight
        • Contact:
    • Massachusetts
      • Boston, Massachusetts, United States, 02114
        • Recruiting
        • Massachusetts General Hospital
        • Principal Investigator:
          • Moussa Mansour
        • Contact:
        • Contact:
      • Fall River, Massachusetts, United States, 02720
        • Recruiting
        • Southcoast Health System
        • Contact:
        • Principal Investigator:
          • Nitesh Sood
    • New Jersey
      • Paramus, New Jersey, United States, 07652
        • Recruiting
        • The Valley Hospital
        • Contact:
        • Contact:
        • Principal Investigator:
          • Mittal Suneet
    • New York
      • New York, New York, United States, 10029
        • Recruiting
        • Icahn School of Medicine at Mount Sinai
        • Contact:
        • Principal Investigator:
          • Srinivas Dukkipati
      • New York, New York, United States, 10075
        • Recruiting
        • Northwell Health Lenox Hill Hospital
        • Principal Investigator:
          • Stavros Mountantonakis
        • Contact:
    • North Carolina
      • Winston-Salem, North Carolina, United States, 27157
        • Recruiting
        • Atrium Health Wake Forest Baptist Medical Center
        • Principal Investigator:
          • Patrick Whalen
        • Contact:
    • Ohio
      • Cincinnati, Ohio, United States, 45220
        • Recruiting
        • Bethesda North Hospital
        • Principal Investigator:
          • Gaurang Gandhi
        • Contact:
      • Columbus, Ohio, United States, 43210
        • Recruiting
        • The Ohio State University Wexner Medical Center
        • Principal Investigator:
          • John Hummel
        • Contact:
      • Columbus, Ohio, United States, 43214-3907
    • Texas
      • Austin, Texas, United States, 78705
        • Recruiting
        • Texas Cardiac Arrhythmia Research Foundation
        • Contact:
        • Principal Investigator:
          • Amin Al-Ahmad
    • Virginia
      • Falls Church, Virginia, United States, 22042
        • Recruiting
        • Inova Fairfax Hospital
        • Principal Investigator:
          • Brett Atwater
        • Contact:
        • Contact:
      • Norfolk, Virginia, United States, 23507
        • Recruiting
        • Sentara Norfolk General Hospital
        • Principal Investigator:
          • Erich Kiehl
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

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)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Pulmonary Vein Isolation Ablation
Pulmonary Vein Isolation Ablation utilizing the Sphere-360 and Affera Mapping and Ablation System
Device: Sphere-360 Pulsed Field Ablation Catheter with the Affera Mapping and Ablation System
Pulmonary Vein Isolation using the Sphere-360 Pulsed Field Ablation Catheter with the Affera Mapping and Ablation System

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Freedom from Atrial Tachyarrhythmia Recurrence Through 12 Months Post-Ablation
Time Frame: Index ablation procedure through 12 months of follow up.
Freedom from documented recurrence of atrial fibrillation, atrial tachycardia, or atrial flutter based on electrocardiographic data through 12 months (365 days) and excluding a 90-day blanking period. The study requires 24-hour Holter monitoring at 6 and 12 months in addition to weekly and symptomatic trans-telephonic monitoring (TTM) transmissions through 12 months, and 12-lead ECGs at all follow up visits. Atrial tachyarrhythmia observed via any of those instruments, as well as acute procedural failure, repeat ablation, cardioversion, an increase in anti-arrhythmic drugs, or use of amiodarone at any time during the study will constitute a failure.
Index ablation procedure through 12 months of follow up.
Incidence of Device- and Procedure-Related Serious Adverse Events Through 6 Months
Time Frame: Index ablation procedure through 6 months of follow up.

Primary safety events (device- and procedure-related serious adverse events, as adjudicated by the Clinical Events Committee) for the Sphere-360 Catheter and Affera Mapping and Ablation System:

Within 7 days: heart block, major bleeding needing transfusion, MI, permanent phrenic nerve paralysis, pulmonary edema, severe pericarditis, significant effusion/tamponade, stroke/CVA, systemic/pulmonary embolism needing intervention, TIA, vagal nerve injury causing esophageal dysmotility/gastroparesis, vascular access complications needing intervention, AKI needing dialysis or hospitalization >48h or prolonged >48h, death, any device/procedure-related CV/pulmonary event causing/prolonging hospitalization >48h (excludes recurrent AF/AT/AFL).

Within 3 months: atrioesophageal/esophago-pericardial fistula, esophageal perforation (device/procedure related; excludes TEE/nasogastric tube injury).

Within 6 months: pulmonary vein stenosis (≥70% diameter reduction).
Index ablation procedure through 6 months of follow up.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Secondary Endpoint: Quality of Life (AFEQT)
Time Frame: Index ablation procedure through 12 months of follow up.
Change in AFEQT score from baseline to 12 months. The AFEQT is an AF-specific health-related quality of life questionnaire, scored 0-100 (higher scores indicate better quality of life).
Index ablation procedure through 12 months of follow up.
Secondary Endpoint: Quality of Life (EQ-5D)
Time Frame: Index ablation procedure through 12 months follow up.
Change in EQ-5D composite score from baseline to 12 months. The EQ-5D is a standardized instrument for generic health status, with composite scores indexed to a US reference population.
Index ablation procedure through 12 months follow up.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Medtronic Cardiac Ablation Solutions

Investigators

  • Principal Investigator: Vivek Reddy, MD, Icahn School of Medicine at Mt Sinai

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 15, 2026

Primary Completion (Estimated)

November 22, 2027

Study Completion (Estimated)

November 22, 2027

Study Registration Dates

First Submitted

December 26, 2025

First Submitted That Met QC Criteria

December 26, 2025

First Posted (Actual)

December 30, 2025

Study Record Updates

Last Update Posted (Actual)

May 22, 2026

Last Update Submitted That Met QC Criteria

May 20, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Horizon 360

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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