Study of the maze procedure treatment for atrial fibrillation with Nd:YAG laser on canines

Objective To modify maze procedure using Nd:YAG laser thermal coagulation in stead of incision so as to simplify the operation,shorten the operation time and reduce postoperative complications.Methods Right thoractomy was performed on 8 dogs and pacing electrode was placed in the distal part of the right atrium near sinoatrial node.Single Burst pacing or Burst pacing on the basis of intravenous acetylcholine chloride infusion to establish the model of persistant atrial fibrillation was performed. It was considered successful when the criteria were met:atrial fibrillation was induced totally by 5 Burst pacing and at least ≥3 episodes of atrial fibrillation for each lasting ≥3 min. Modified laser maze procedure under cardiopulmonary bypass was performed on the 8 dogs in which atrial fibrillation has been successfully induced. The same type of stimulation was used to observe whether it can induce atrial fibrillation postoperatively.Results Persistant atrial fibrillation was successfully induced in 8 dogs in which single Burst pacing or Burst pacing with acetylcholine chloride infusion was applied. After laser maze procedure Ⅲ modified,atrial fibrillation could not be induced in the same 8 dogs. Conclusions A certain amount of laser energy can cause transmural necrosis and lose electrophysiological conduction function in the atrial myocardium. Nd:YAG laser thermal coagulation can be used to replace incision in the treatment of atrial fibrillation with maze procedure.