Surgical Ablation Versus No Surgical Ablation for Patients With Atrial Fibrillation Undergoing Mitral Valve Surgery

The purpose of the research is to determine whether treating atrial fibrillation with surgical ablation during scheduled mitral valve surgery is better than mitral valve surgery by itself without the surgical ablation. Surgical ablation of atrial fibrillation is a technique used by surgeons to deaden atrial heart tissue and block electrical signals that may be causing your heart to beat irregularly. There are no new procedures being tested in this study; both mitral valve surgery and surgical ablation are used regularly in patients who have mitral valve problems and atrial fibrillation, although no surgical ablation devices have been approved by the Food and Drug Administration for the treatment of atrial fibrillation. What is not known with certainty, is whether patients with atrial fibrillation who are having planned mitral valve surgery would do better if they also had surgical ablation rather than medication alone to treat their atrial fibrillation.

The purpose of this study is to determine whether the addition of surgical ablation to planned mitral valve surgery for patients with persistent or longstanding persistent AF (within 6 months prior to randomization) reduces the incidence of postoperative heart arrhythmia compared to mitral valve repair with medication therapy alone. This is a randomized, multi-center trial which will enroll 260 subjects who will be randomized in a 1:1 fashion to: (a) mitral valve surgery plus surgical ablation or (b) mitral valve surgery without ablation (control group). All patients will undergo ligation or excision of the left atrial appendage. Patients assigned to the ablation group will be further randomized (1:1) to one of two lesion sets: (1) pulmonary vein isolation only or (2) biatrial Maze lesions. The target population for this trial consists of adult patients with mitral valve disease requiring surgical intervention and persistent or longstanding persistent atrial fibrillation. All patients who meet the eligibility criteria may be included in the study regardless of gender, race or ethnicity. The primary efficacy endpoint is freedom from AF, which will be measured by 3-day continuous monitoring at 6 months and 12 months post-ablation. The primary safety endpoint is a composite of death, stroke, serious cardiac events (heart failure, myocardial infarction), cardiac re-hospitalizations, transient ischemic attack, pulmonary embolism, peripheral embolism, excessive bleeding, deep sternal wound infection/mediastinitis, damage to specialized conduction system requiring permanent pacemaker, damage to peripheral structures, such as the esophagus, within 30 days post-procedure or hospital discharge (whichever is later).

Eligibility Criteria:
Inclusion Criteria:

* Able to sign Informed Consent and Release of Medical Information forms
* Age ≥ 18 years
* Clinical indications for mitral valve surgery for the following:

  1. Organic mitral valve disease; or
  2. Functional non-ischemic mitral regurgitation; or
  3. Ischemic mitral regurgitation with evidence of concomitant structural mitral valve disease

Note: May include need for surgical management of functional tricuspid regurgitation or patent foramen ovale. May also include concomitant CABG, aortic arch or aortic valve procedure. Surgical intervention may be performed via sternotomy or minimally invasive procedure.

* a) Persistent AF within 6 months prior to randomization, defined as non self-terminating AF lasting greater than 7 days but no more than one year, or lasting less than 7 days but necessitating pharmacologic or electrical cardioversion.

  * Duration of AF must be documented by medical history and
  * Presence of AF must be documented by a direct electrocardiographic assessment within 6 months prior to randomization.
* b) Longstanding persistent AF is defined as continuous AF of greater than one year duration.

  * Duration of AF must be documented by medical history and
  * Presence of AF must be documented by a direct electrocardiographic assessment upon arrival in the OR.
* Able to use heart rhythm monitor

Exclusion Criteria:

* 1. AF without indication for mitral valve surgery 2. AF is paroxysmal 3. Evidence of left atrial thrombus by intra-operative TEE 4. Evidence of active infection 5. Mental impairment or other conditions that may not allow subject to understand the nature, significance, and scope of study 6. Surgical management of hypertrophic obstructive cardiomyopathy 7. Previous catheter ablation for AF 8. Life expectancy of less than one year 9. Absolute contraindications for anticoagulation therapy 10. Enrollment in concomitant drug or device trials 11. Uncontrolled hypo- or hyperthyroidism 12. FEV1 \< 30% of predicted value and/or need for home oxygen therapy 13. Women who are pregnant as evidenced by positive pregnancy test 14. Women of childbearing age who do not agree to be on adequate birth control throughout the period of the trial.