NCT07308847 · Medtronic Cardiac Ablation Solutions
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)
What this study is about
The study is a forward-looking, single-treatment group$1, 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.
View original scientific description
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.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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:
- a physician's note indicating at least 2 symptomatic PAF episodes occurring within 6 months prior to enrollment; and
- at least 1 electrocardiographically documented episode within 12 months prior to enrollment
- Adults who are ≥18 and ≤80 years of age on the day of enrollment.
- Willing and able to comply with all baseline and follow-up evaluations for the full length of the study.
Exclusion criteria
- 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
- AF that required three (3) or more distinct cardioversions in the preceding 12 months.
- LA anteroposterior \> 5.0 cm (by MRI, CT, or TTE)
- 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
- 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
- Patient who is not on oral anticoagulation therapy for at least 3 weeks prior to the ablation procedure
- 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)
- Presence of any pulmonary vein stents
- Known pre-existing pulmonary vein stenosis
- Pre-existing hemidiaphragmatic paralysis
- Prior valvular (surgical or percutaneous) procedure including prosthetic, bioprosthetic, valve replacement, valve repair or valvuloplasty, and any prior atriotomy
- Moderate to severe aortic or mitral valve stenosis
- Moderate to severe mitral regurgitation (i.e., 3+ or 4+ MR)
- Any cardiac surgery, myocardial infarction, PCI / PTCA or coronary artery stenting which occurred during the 3-month interval preceding the consent date
- Unstable angina
- 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)
- Severe lung disease, primary pulmonary hypertension, or any lung disease with abnormal blood gases or requiring supplemental oxygen
- Rheumatic heart disease
- Severe thrombocytosis, thrombocytopenia, or any bleeding or clotting disorder
- Contraindication to or unwillingness to use systemic anticoagulation
- Documented left atrial thrombus on imaging
- Active systemic infection or sepsis
- Hypertrophic cardiomyopathy
- Known reversible causes of AF, including but not limited to uncontrolled hyperthyroidism, severe untreated obstructive sleep apnea, and acute alcohol toxicity
- Any cerebral ischemic event (strokes or TIAs) which occurred during the 6-month interval preceding the consent date
- Carotid stenting or endarterectomy
- History of thromboembolic event within the past 6 months or evidence of intracardiac thrombus at the time of the procedure
- 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
- Patient with life expectancy that makes it unlikely 12 months of follow-up will be completed
- 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
- Known allergies or hypersensitivities to adhesives
- Body mass index \> 40 kg/m2
- Atrial myxoma
- Significant restrictive or obstructive pulmonary disease or chronic respiratory condition.
- 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
- Solid organ or hematologic transplant, or currently being evaluated for an organ transplant
- Presence of intramural thrombus, tumor, or other abnormality that precludes vascular access, catheter introduction, or manipulation
- Known drug or alcohol dependency
- 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.
- Treatment with Amiodarone within the 3 months prior to enrollment
- Amyloid heart disease (cardiac amyloidosis)
Where
- Jonesboro, Arkansas
- La Jolla, California
- Naples, Florida
- Savannah, Georgia
- Chicago, Illinois
- Boston, Massachusetts
- Fall River, Massachusetts
- Minneapolis, Minnesota
- Rochester, Minnesota
- Paramus, New Jersey
- New York, New York
- Durham, North Carolina
And 8 more locations — see the full list below.
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 12, 2026 · Source of record for eligibility and locations