So we're going to switch gears. I talked about catheter ablation, and next we're going to talk about surgical ablation for patients with atrial fibrillation. This is a little more time, but it's still a case-based presentation. This is a 72-year-old man who has asymptomatic severe mitral regurgitation with normal LV function. And it actually, I thought about this case when David Haynes presented the 50-year-old with asymptomatic atrial fibrillation. When do we pull the trigger? Traditionally, with AFib, we pull the trigger when patients have symptoms. In patients with mitral regurgitation, if they're asymptomatic, we tend to follow their ejection fraction. And maybe we should have ideas like this for AFib, is if someone's truly asymptomatic, but their EF falls, that's an indication to treat. But typically, for mitral valve disease, you treat this when patients either develop symptoms, ventricular dysfunction or ventricular enlargement, or atrial fibrillation. That continues to be an indication to proceed with surgery, suggesting that the atrial fibrillation is a sign of stress on the left atrium from the mitral regurgitation. So last summer, he developed nuanced atrial fibrillation. In October, he underwent a minithoracotomy mitral valve repair with an aneuplasty ring with a COX-3 maze procedure with cryoablation, this is just verbatim from the medical records, with Atricure, with a left atrial appendage closure with internal ligation, not amputation or a clip, and then closure of a PFO. So that's a reasonable description. It's often hard to even get that much from the op note. In November, the next month, he saw one of my colleagues. I just saw this patient last week. He saw my colleague, and in November of 2019, had this EKG, and I don't know how many electrocardiographers we have in the room, but this is an irregular rhythm, and you can look in the lead that's of most value, and we're looking at atrial activity, which is V1, which is sitting over the right atrium, and you can see regular atrial activity, and you can see a perfectly regular organized flutter wave, so it's not atrial fibrillation, but it's atrial flutter. It's not evident well on other leads, but the ventricular response has grouped beating, suggesting that the atrial rhythm is organized, and it's not just coarse atrial fibrillation. So this is atypical atrial flutter. This is in a patient after a maze procedure, almost always due to the left atrial ablation, either reconnection of some critical structure, like the pulmonary veins that were isolated, a gap in the line of the linear lines that they make, or just another source that's not protected from the maze procedure. In November, that was when he developed atrial flutter. He was put on anticoagulation. He came in for a cardioversion, and this is the story. I wasn't there that day, but he came in. His INR was 1.8. We can debate whether that's good enough. Usually what should have happened is he was given either a dose of Lominox or switched to a NOAC. I don't know why he was on Coumadin to begin with, and a TEE could be done. When you ask some patients if they want a TEE or have had one in the past, they're not too excited usually about that. And then the patient went home, and they never followed up. He came back to the ER after he fell, and it's still a little unclear because he has some retrograde amnesia, whether he had syncope or fell. We did an echo that shows his mitral valve that they operated on looks fine. His LV function is still normal. The likelihood he had some valve-related cause for syncope or a ventricular arrhythmia is pretty low with those findings. So the question is, could he have had syncope from the atrial flutter? He was still on atrial flutter, so he hadn't converted. And I saw him last week, and he's still on atrial flutter. EKG looks pretty much the same. So just to take a step back, should a maze surgery, since that's kind of the topic here, keep this in mind. Should that have been done when he had his mitral valve repair? He had intermittent atrial fibrillation, and he was undergoing cardiac surgery. And then when you hear the term maze or Cox 3 or Cox 4 maze procedure, what does that really mean? And Jim Cox is no longer operating, but he's on faculty here. I should have had him here to explain the following. And he will tell you that there's data that in patients who undergo mitral valve disease who have atrial fibrillation, if they undergo ablation or ablation surgery and remain in sinus rhythm, that they have better outcomes. There's other data that if you treat the atrial fibrillation at the time of surgery versus not treat it, that your survival is comparable to patients who don't have atrial fibrillations from Rick Lee, who used to be here on faculty in the Journal of Thoracic Cardiovascular Surgery. And so this is translated into the guidelines for the surgeons, and we all are familiar with our own guidelines and the Heart Rhythm Society guidelines, for example. But I think it's important to appreciate what our peers' guidelines also reflect. And if you are having concomitant AF surgery, as opposed to the language they use is standalone versus concomitant. If you're undergoing mitral valve surgery and you have atrial fibrillation, it's a class one level A recommendation to have AFib surgery. And still, despite this, across the country, it's often not performed. And I think the reason is the surgeon's not trained to do this, not comfortable doing it. There's a perception that it's going to add a significant amount of time. It may add a significant amount of cost to the supplies of the procedure. If patients are having bypass AVR or both, it's also a class one recommendation with a level of evidence B. There's evidence. Interestingly, this was put as a class recommendation, but there is no evidence that it increases operative mortality and that also does not affect operative morbidity. And that's called a class one A recommendation. So the point is that in the surgical world, if someone has mitral valve disease and atrial fibrillation, they should do something when they're in the OR. The question is, you know, what is something and what is a Cox-Mays procedure? Well, Jim Cox came up with this notion when he was at Wash U of how can we surgically interrupt atrial fibrillation, which was largely understood at the time as multiple wavelets of reentry in both the right and left atrium. And if we can section up the atrium to create a maze, then we will maintain intact conduction during sinus rhythm. We can't just chop up the atrium or we'll end up with intra-atrial block or heart block. But in sinus rhythm, if the sinus node can make it to the AV node and over the hysperkinesis system, but if there's atrial fibrillation, it runs into roadblocks and it's in a maze, then that should eliminate atrial fibrillation. And there were different versions. There's the Cox-1-Mays procedure that involved pulmonary vein isolation using a roof line, removal of the left atrial appendage, removal of the right atrial appendage, a lesion from the pulmonary vein to the left atrial appendage, a lesion from what's called the mitral isthmus in the left atrium, including a lesion of the coronary sinus. And then right atrial lesions in a way that didn't damage the sinus node and would not result in sinus arrest post-op. They modified these procedures. You can see this line here is across the inter-atrial connection or Bachman's bundle. They eliminated that lesion to maintain conduction from right atrium to left atrium. So you don't see that line here anymore. And they kind of moved this down closer away from the roof, but completed a line to the IVC. The one place, interestingly, that the surgeons can't get to, which still kind of fascinates me, is the cavo-tricuspid isthmus that's probably the most accessible thing for us to ablate for typical flutter, but they can't easily ablate the tissue between the tricuspid valve and the inferior vena cava without opening the right atrium. Again, this was modified slightly for the MAZE 3 procedure, a Cox MAZE procedure, by changing some of the right atrial lines. And then what's called the Cox IV procedure, which is kind of a redundant way, and this is often, I think, what's done in patients who have mitral valve surgery. They go through the right chest, and they get to the right atrium, and they go underneath it into the space between right and left atrium and enter what they call Watterson's groove. They get into the left atrium, and then they want to isolate the pulmonary veins to create a box lesion, so they'll put a clamp from the intra-atrial septum to here, and another one here, but because they don't touch, you're kind of left with two arc-like lesions. To connect these, they'll make a circle around the left pulmonary vein pairs, and then they'll also isolate the right pulmonary vein. So in many patients who have had a MAZE procedure, really that's all that's done. For a full Cox MAZE 4 procedure, these additional ablation lines are done, including removing left atrial appendage and ablating down by the mitral isthmus, and so Dr. Cox is quick to point out that these are other things that people do in the OR, but none of these is a MAZE procedure, and I'm sure people in this room that are in that industry recognize that surgery for atrial fibrillation can mean a lot of different things, and for us to even bring a patient to the EP lab without the operative notes, very difficult. You can map the atrium and try to estimate where the scar is from the prior lesions, but it's very useful to know where they made those lesions so that you can be quick about your goals, and for example, we've had patients that come back, and they've had this box lesion made after mitral valve surgery, and when you map, the veins are reconnected, and the whole posterior left atrium is activated, and so it's not really clear what they had done before, so you start isolating the veins, and you'll reach a certain point, and boom, you'll isolate the whole posterior wall, when if you could have found that spot at the beginning, it may have been that one little gap here was responsible for the whole reconnection of the posterior wall, and if you could identify that, you could be limited in your ablation, and we kind of tend to start from scratch and isolate the entire pulmonary vein system again, so that's some nomenclature, but I think there's some true appreciation that some of these lesion sets are not complete enough to eliminate particularly persistent atrial fibrillation, so there are other ways to do this, you know, the hope was to talk about one case, but just to be complete, there's concomitant AF surgery, and there's standalone AF surgery, so we occasionally will take patients who have had catheter ablation, don't have an indication for cardiac surgery, don't need mitral valve surgery, for example, but have had a couple ablation procedures, and unlike the patient I just presented, where they have atrial flutter in the septum, they've got a dilated atrium, it's not really clear what more should be done, that's an ongoing debate in EP, probably the biggest one is what do you do for persistent AFib beyond isolating the pulmonary veins, and the surgeons can go in and do a more extensive procedure, they will do this often in a minimally invasive way or perform what they call a TT maze, and they're able to perform these hybrid procedures with a limited thoracotomy, this is not a patient of mine, Jim Cox got this from another surgeon and showed that with two ports and a scope, they were able to perform a hybrid surgical procedure for atrial fibrillation off pump. There are a whole host of other approaches, many of you may be familiar with what's called a convergent procedure, which is a procedure that really is a surgical technique to ablate the entire posterior wall with the hope of isolating as much as possible the pulmonary veins, but usually doesn't result in complete PVI, and so it's often a staged procedure, either during the same hospitalization or to bring the patients back to fill in any gaps and the pericardial reflections don't allow them to kind of get up around the top of these veins, so it often requires, if the goal is isolation, to either have done that to the veins before this part or after, and this has also evolved from making a box to, well, let's not rely so much on these lines, it can just get a gap, let's just ablate the whole posterior wall, it's also evolving from a trans-diaphragmatic approach from the starting in the abdomen to an intrapericardial approach to put this catheter up behind the left atrium. So when I saw this patient in clinic last week, I read those records, I thought about this case, and I had a lot of questions that was internally ligated, there's plenty of data that when surgeons close a left atrium with a stitch, it doesn't always stay shut, he's going to need to be cardioverted, is coumadin enough to rule out a clot in a half-closed appendage, and so even though he's now therapeutic on his coumadin, I convinced him to have another TEE. Where's this flutter coming from? All bets are off when someone's had surgery, we just had a patient who had had a previous ablation somewhere else, it sounded fairly extensive, they came in with flutter, it didn't look like typical flutter, and sure enough, it was coming from the cavo-tricuspid isthmus, because the morphology of the flutter waves can be altered in patients who have had prior procedures. So then, do we just cardiovert them, do we bring them back to do another ablation, do we go back and look at the pulmonary veins to see if they're isolated, you know, what's the next step? And so I think I'll save that for the discussion. Thank you.

surgical ablation

atrial fibrillation

minithoracotomy mitral valve repair

Cox-3 maze procedure

cryoablation