[Electrophysiologic study in arrhythmia surgery]

The traditional paradigm in surgery for cardiac arrhythmias has been the electrophysiological assessment of the arrhythmia followed by the determination of a specific lesion set for the ablation or a definitive procedure based on the results of the analysis in each patient. The maze procedure was developed as a definitive procedure for atrial fibrillation (AF) and was not guided by electrophysiologic findings in individual patients. The rationale behind the maze procedure is to create a line of conduction block to prevent the propagation of repetitive activations from the pulmonary veins toward the left atrium and to block the reentrant activations occurring on the atrial wall. The cut-and-sew technique is the most reliable method to accomplish conduction block. However, it extends the cardiac arrest and cardiopulmonary times and increases the risk of bleeding. During the past decade, a number of ablation devices have been developed and tested in animals and humans for their ability to create complete conduction block. The use of ablation devices enables less invasive AF surgery. However, the non-transmural or non-contiguous necrosis caused by an incomplete ablation can permit conduction across the ablation line and impair the efficacy of the surgery. Intraoperative verification of conduction block is mandatory to assure the transmurality and contiguity of the lesions created by the ablation devices.