What are the take home messages from ISMICS for the surgeon interested in surgical control of ablation?

1. What are the take home messages from ISMICS for the surgeon interested in surgical control of ablation? • That adhering to the concepts of isolation of the probable ectopic triggers, as well as ablation of the macro re-entry circuit pathways is essential to get good results • That goals can be achieved through incision or through all energy sources • Cryo is the safest energy source from an endocardial perspective

2. What are the major strengths and limitations of cryo? • It has been proven to be as efficacious as the “cut and sew” Maze procedure. • Simple to use, fast, very little likelihood of collateral injury • Its utility in an epicardial fashion is in question, many want an off-pump beating heart platform with which they can obtain efficacy that rivals the Cox Maze. Whether that’s possible at all remains to be seen. • With cryothermia there is a heat sink effect from the blood moving past the endocardium, creating uncertainty in the epicardial approach • With the Frostbite device, we can clamp the tissue within the jaws and temporarily interrupt that flow of blood, may allow this technology to be applied epicardially

3. Is there an ideal lesion pattern? • There are as many modifications of the Maze procedure as there are surgeons • The one lesion pattern that we know works for all forms of supraventricular arrhythmias is the Cox-Maze III lesion set • It is difficult to say which modified lesion sets work and in what instances, Maze III is probably not needed for all cases • There is no standard nomenclatureand everyone has to describe their lesion set clearly • The more lesion lines you make the more likelihood of success, both for atrial fibrillation and for preventing recurring atrial flutter • Different energy sources have inherent limitations, cryo is the safest • Many of the operative procedures seem to be modified to fit the technology rather than the principles espoused by Doctor Cox

4. What is the next major question that needs to be answered in the field? • A large, standardized, prospective study of lesion sets • Must determine what the characteristics are that may require larger lesion sets • For instance, paroxysmal atrial fibrillation may be able to be treated solely with pulmonary vein isolation and ablation of the left atrial appendage • No clear answer yet

5. Why aren’t more atrial fibrillation surgeries being done? • Many surgeons feel atrial fibrillation is only a nuisance that can be adequately treated with Coumadin • The Maze procedure is daunting, they don’t know that other energy sources are equally effective • Many surgeons are reluctant to extend the length of the operating time by adding this procedure to a very sick patient • Surgeons may change their mind when the long-term consequences in morbidity and mortality from the presence of atrial fibrillation are made clear