aMAZE Study for Atrial Fibrillation (aMAZE)

Between 400 and 600 subjects with symptomatic persistent or longstanding persistent Atrial
Fibrillation (AF) will be randomized to the LARIAT system in addition to Pulmonary Vein
Isolation (PVI) catheter ablation Treatment Group or the Control group, using Pulmonary Vein
Isolation (PVI) catheter ablation using contact force sensing and irrigated radio frequency
catheter approved by the FDA for the treatment of Atrial Fibrillation.

This study will be conducted in two stages:

- Limited Early Stage (Stage 1): up to 175 subjects at up to 15 sites

- Pivotal Stage (Stage 2): up to 600 subjects at up to 50 sites All patients from both
stages will be included in the primary analysis.

Inclusion Criteria:

- Documented diagnosis of symptomatic persistent or longstanding persistent
non-valvular atrial fibrillation

- Failed at least one Class I or III Antiarrythmic Drug (AAD)

- Life expectancy ≥ 1 year;

- Willing and able to return to and comply with scheduled follow-up visits and tests;
and

- Willing and able to provide written informed consent

Exclusion Criteria:

- Prior procedure involving opening of the pericardium or entering the pericardial
space (e.g., coronary artery bypass graft, heart transplantation, valve surgery)
where adhesions are suspected;

- Prior epicardial or endocardial atrial fibrillation ablation procedure;

- LA diameter > 6 cm as measured by computerized tomography;

- Documented embolic stroke, transient ischemic attachor suspected neurologic event
within 3 months prior to the planned intervention;

- Currently exhibits New York Heart Association Class IV heart failure symptoms;

- Documented history of right heart failure specifically when right ventricle exceeds
the left ventricular size;

- Documented history of myocardial infarction (MI) within 3 months prior to the planned
study intervention;

- Documented history of unstable angina within 3 months prior to the planned study
intervention;

- Documented symptomatic carotid disease, defined as > 70% stenosis or > 50% stenosis
with symptoms;

- End Stage Renal Disease (ESRD) or documented history of renal replacement / dialysis;

- Current documented history of clinically significant liver disease which predisposes
the subject to significant bleeding risk (clinically defined by the treating
physician);

- Any history of thoracic radiation with the exception of localized radiation treatment
for breast cancer;

- Current documented use of long-term treatment with corticoid steroids, not including
use of inhaled steroids for respiratory diseases;

- Active pericarditis;

- Active endocarditis;

- Any documented history or autoimmune disease associated with pericarditis;

- Evidence of Pectus Excavatum (documented and clinically defined by the treating
physician);

- Untreated severe scoliosis (documented and clinically defined by treating physician);

- Documented Left Ventricular Ejection Fraction (LVEF) < 30% within 30 days prior to
planned intervention;

- Documented presence of implanted congenital defect closure devices, (e.g., atrial
septal defect, patent foramen ovale or ventricular septal defect device);

- Previously attempted occlusion of the left atrial appendage (by any surgical or
percutaneous method);

- Body Mass Index (BMI) > 40;

- Evidence of active Graves disease;

Additional Exclusion Criteria: Based on Screening / Pre-procedure Imaging

Subjects will also be excluded if they meet any of the following:

Based on screening computed tomography angiography performed within 90 days prior to study
intervention as confirmed by the core lab:

Left atrial appendage morphology: Superior-posterior oriented left atrial appendage (i.e.
superior C shape), that has:

- Left atrial appendage LARIAT-approach width ≥ 40 mm; or

- Left atrial appendage distal apex extending posterior to the ostium of the appendage.

- Left atrial appendage positioned behind the pulmonary artery; or

- All other left atrial morphology: Left atrial appendage LARIAT approach width > 45
mm.

- Based on a peri-procedural imaging (transesophageal echocardiography) at time of
LARIAT or catheter ablation) and confirmed by institution's designated LARIAT
echocardiographer:

- Intracardiac thrombus; or

- Significant mitral valve stenosis (i.e., mitral valve stenosis < 1.5cm2