BoxX-NoAF Clinical Trial

Inclusion Criteria:

• Planned and clinically indicated for cardiac surgical procedure requiring cardiacbypass and opening of the pericardium

• Age ≥ 65 years and CHA2DS2-VASc ≥ 3

Exclusion Criteria:

• Documented history of atrial fibrillation or atrial flutter anytime prior to thecardiac surgery

• Prior procedure involving opening the pericardium or entering the pericardial space

• Patients undergoing off-pump surgery

• Prior LAA occlusion, exclusion, or removal (surgical or percutaneous)

• Presence of a permanent pacemaker

• Infiltrative cardiomyopathies (i.e. amyloidosis)

• Planned cardiac surgical procedure using non-sternotomy approaches

• Patients whose planned procedure is a heart transplant or implantation of anylong-term ventricular assist devices

• Presence of ventricular arrhythmia

• Active endocarditis

• NYHA Class IV heart failure symptoms

• Preoperative need for an intra-aortic ballon pump or intravenous inotropes

• Active systemic infection at the time of cardiac surgery requiring antibiotics

• Known allergy to Nitinol or nickel sensitivity

• Known medical condition with expected survival of less than 1 year

• Other comorbidities that in the Investigator's opinion make the subject unsuitablecandidate to complete the protocol required intervention or visits

• Current enrollment in an investigation or trial or an investigational devices orinvestigational drug that would interfere with this trial

• Mental impairment or other psychiatric conditions which may not allow the patient tounderstand the nature, significance, and scope of the trial.

• Pregnancy

• Known severe symptomatic carotid disease