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Atrial fibrillation (AF), the most common arrhythmia in adults, affects 1 in 25 people over the age of 60 years and 1 in 10 over the age of 80 years. 1 There is considerable morbidity, mortality and economic burden associated with AF, all of which will increase with the expanding elderly population. Until recently, pharmacologic therapy with AV nodal blocking agents, antiarrhythmics and anticoagulation were the mainstay of therapy. Although electrical cardioversion is associated with a high immediate success rate, most patients have recurrences of AF with only 23% remaining in sinus rhythm one year after cardioversion. 2 Antiarrhythmic agents have been shown to improve sinus maintenance, but these medications have variable success and are associated with many potentially serious side effects. In addition, the recently published AFFIRM trial suggests that a pharmacological rhythm control strategy has no benefit in terms of mortality or morbidity over a rate control and anticoagulation strategy. 3 Over the last few years, there has been a great deal of enthusiasm regarding catheter based ablation strategies aimed at curing AF. Percutaneous Maze ProcedureIn 1959 Moe theorized that AF resulted from multiple wavelets of reentry. With this in mind, Cox performed the surgical Maze procedure in 1991. 4 The Maze procedure alters the arrhythmogenic substrate by interrupting the macroreenterant circuits and reducing the critical mass of atria needed to sustain AF. This surgical approach currently is preformed in association with coronary bypass surgery and/or mitral valve repair and is successful in curing AF in 75-90% of cases. 5 Although the surgical procedure has been modified over time, the approach has consistently included isolation of the pulmonary veins (PV). Currently, malleable hand-held catheters are being used to create linear lesions with conventional radiofrequency energy, rather than surgical incisions.The surgical experience over the past decade has provided evidence that the left atrium plays a significant role in the maintenance of AF and that a reduction in the left atrial mass prevents maintenance of AF. Because an open chest procedure is associated with significant morbidity, attempts have been made to replicate the Maze procedure using a percutaneous, catheter-based approach. The MECA (Multiple Electrode Catheter Ablation) trial, sponsored by Boston Scientific/EP technologies, was designed to determine the safety and feasibility of specially designed catheters with multiple large electrodes used to create circular, biatrial linear Indian Pacing and Electrophysiology Journal (ISSN 0972-6292), 3(4): 210-223 (2003)

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