Outcomes and predictors of success of a radiofrequency- or cryothermy-simplified left-sided maze procedure in patients undergoing mitral valve surgery.

BACKGROUND AND AIM OF THE STUDY: Restoration of sinus rhythm with a maze procedure after concomitant mitral valve (MV) surgery has been shown to reduce the rate of stroke and improve cardiac function and quality of life compared to MV surgery alone. Unlike the classical Cox-Maze III operation, a simplified left-sided maze procedure can be performed without any significant increase in operative complexity.

METHODS: Outcomes were compared retrospectively between radiofrequency (RF) and cryothermy as an energy source and analyzed predictors of outcome in 73 consecutive patients undergoing MV surgery with a concomitant simplified left-sided maze procedure. Clinical characteristics as well as rhythm and complication rate at follow up were assessed by review of medical records and patient and physician interview.

RESULTS: There were no complications associated directly with the maze procedure. At an average follow up of 342 days, 69% of patients were in normal sinus rhythm. Of the remainder, 30% had recurrent atrial fibrillation (AF) and 1% atrial flutter. In addition, 7% of patients required cardioversion and 14% required anti-arrhythmic therapy to maintain sinus rhythm. Patients with recurrent AF were more likely to have an enlarged right atrium or Carpentier Type IIIa mitral regurgitation on preoperative echocardiography, and more likely to have undergone concomitant aortic or tricuspid valve surgery. There was no difference in outcome between RF and cryothermy as an energy source in unadjusted or adjusted analyses.

CONCLUSION: The results of the study helped to establish RF- or cryothermy-simplified left-sided maze procedure as being efficacious and without associated complications in patients having MV surgery and a history of AF. Further investigations are warranted to better define the clinical predictors of recurrent AF to improve patient selection and potentially to modify current maze techniques.