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Dr. Saqib Masroor - Atrial Fibrillation

In this episode of Prescribed Listening from The University of Toledo Medical Center, Cardiothoracic Surgeon Dr. Saqib Masroor discusses his speciality, cardiovascular health.








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(gentle music) - Welcome to "Prescribed Listening" from the university of Toledo Medical Center, each week, UTMC providers sharing insight into their medical specialty. This week, Dr. Saqib Masroor. - My name is Saqib Masroor. I'm the Chief of Cardiothoracic Surgery at University of Toledo Medical Center, and I'm the associate professor at the School of Medicine. Atrial fibrillation, or AFib as it is known, or some people call it AF, it's the irregular heartbeat of the upper chambers of the heart. As you may imagine, the lower chambers of the heart are the ones that pump blood out of the heart, and if they do not beat at a regular rate, then that is not compatible with life. But, the upper chambers are a conduit for blood flow to the lower chambers, and therefore, they can fibrillate, and patients can live with that rhythm. Most of people do that without any hemodynamic problems, or problems with their blood pressure. However, this rhythm can be associated with a lot of problems longterm. Many people do not know that they have atrial fibrillation. The other thing is, there's a little windsock-like cavity in the upper chamber, on the left side, called the left atrial appendage, and if the heart chambers are not squeezing blood out, blood can stagnate in that windsock, or just sit there, and when blood sits anywhere, it makes clots, and those clots can find their way down into the lower chamber, out of the heart, and can cause stroke, and clots in the legs and bowels, causing potentially fatal problems. Also, some people do not tolerate this irregular heartbeat very well, and the heart goes into rapid rates, and they feel short of breath, and they cannot do anything, they are fatigued. And thirdly, longterm, some people develop heart failure because of this irregular rhythm. So, this rhythm, while compatible with life, can be dangerous in many people. It's been associated, if you look teleologically, with the size of a human body and the size of the heart. If you look at small animals like cats and dogs, they are never in atrial fibrillation. Humans are atrial fibrillation about maybe 1% of us. Horses have atrial fibrillation, most of them have atrial fibrillation. So, the size of the heart and how much blood it has to pump out is an indication of which species will develop atrial fibrillation. High blood pressure, heart disease, coronary artery disease, valvular disease, diabetes, they're all associated with a higher incidence of atrial fibrillation, and also, obstructive sleep apnea is associated with atrial fibrillation. Asymptomatic, or ones who don't have symptoms, they really don't know atrial fibrillation until they go into the hospital for some other reason, or they develop a sudden stroke, and they find out that they have atrial fibrillation, but the ones that do develop symptoms, the most common symptoms are shortness of breath, fatigue, not being able to do as much as they used to do. There are two things when you talk

about treating atrial fibrillation: 3:17

one is treating the rhythm, making the person not stay in atrial fibrillation anymore, and the other is to prevent the complications associated with AFib. So, antiarrhythmic drugs are not very good at maintaining rhythm longterm. Part of the problem is they can have adverse effects, and patients may tolerate, so even if they work, patient gets other irregular rhythms, or they have other toxicity or adverse effects related to it, and they cannot take those drugs longterm. So, antiarrhythmic drugs are not very helpful in keeping the person in sinus rhythm. Beta blockers is a class of medicine that slows down the heart rate, so patients who have AFib associated with rapid heart rate, they can benefit by slowing down their heart rates. So, that's symptomatic treatment, that's not treating atrial fibrillation. The other complication, as I mentioned earlier, is the risk of making clots inside the heart, which can go and cause stroke. To prevent that, traditionally, for many years, the treatment has been blood thinners. So, you keep the blood thin so it doesn't clot, and traditionally that has been better than no blood thinners, in reducing the risk of stroke, although it comes at a risk of bleeding complications, but that's been how people have managed this for a long time. The history of interventions for treatment of AFib really goes back to the surgery for atrial fibrillation. Dr. Cox did a lot of research, and developed a procedure, which went through many iterations, and became the Cox maze procedure, where you would stop the heart, and cut the upper chambers into different pieces, and then sew them back again, the idea being that the scar that forms as a result of those cuts, prevents the spread of these irregular rhythms, and treats atrial fibrillation, and that has been the gold standard for the treatment of AFib since the early '90s. However, as you can imagine, it's a big operation, and for many patients who don't even know they have AFib, or they can live along with just blood thinners, there was hesitation in recommending that surgery for someone. Then, minimally invasive procedures came along, and Dr. Cox, himself, did some work using cryoenergy, meaning freezing the heart, instead of cutting and sewing, freezing the heart along the same lines, and freezing did the same thing: It killed the cells, and the dead cells were replaced by a scar. And that procedure has also been very successful. Cryomaze procedure is a minimally invasive procedure that involves creating similar lines to the Cox maze procedure, inside the heart, and then freezing the two along those lines, but also, at the same time, we occlude the left atrial appendage. The windsock that I was talking about earlier, we totally occlude that space by either putting a clip from the outside, and the clip just pinches it shut, so there's no more space for the blood to just sit and make a clot. So, combined with the cryomaze procedure, which has a success rate in excess of 90% in treating atrial fibrillation, and combining that with the clip, the risk of complication from atrial fibrillation are significantly reduced in patients who undergo this procedure. So, we've done this procedure for a number of years, and I've been involved in it for more than 15 years, and pretty much anyone who has symptoms from atrial fibrillation, and is unable to be treated with antiarrhythmic drugs or cardio versions, which cardio version is basically, you deliver a DC electrical shock that resets the heart rhythm, and many times, atrial fibrillation, in its early stages of development, can be converted into sinus rhythm. Atrial fibrillation can be treated with cryomaze in most patients, except in the very elderly and frail, and especially people who cannot take blood thinners for other reasons. I know some police officers develop atrial fibrillation, and they didn't want to take blood thinner, they would be given a desk job. Pilots... So, certain professions, even if they are low risk, they prefer to have not been sinus rhythm because that's a problem for them keeping their job. We really consider it for many patients who have symptoms of heart failure, or decreased heart function, or who are symptomatic and are not able to maintain their endurance capacities because of AFib, are candidates for this. And then, around 1995 and later on, some research was done using catheter ablations. That procedure has evolved over time; the technique and the lesion sets, the lines that they make in the cath lab by the electrophysiologist have evolved over time, and the success rate of that procedure has improved. That is, for a subset of patients who are more likely to benefit from that. Not every patient is a candidate for procedure. So, that is a catheter ablation for atrial fibrillation, using, most of the time, radiofrequency ablation. More recently, cryoballoons have been used, which are similar to the catheter ablation, except instead of using catheters to burn the tissues around, the cryoballoons freeze the tissues, and try to recreate the effect of scarring, as we did in the surgical cryomaze procedure. Catheter ablation is a safe procedure. As I mentioned, the procedure itself has undergone some iterations, and now it's very safe, but it's relatively useful in people with paroxysmal atrial fibrillation. Paroxysmals AF patients are those who have episodes of AFib, which don't last very long, and then they can convert, but during those paroxysms, they're very symptomatic. Usually, it is understood that that is an earlier stage of AFib. If it stays on over long time, they become permanent or chronic atrial fibrillation, and persistent or chronic atrial fibrillation is one that stays in atrial fibrillation, and can be treated with either catheter or surgical ablation. The third type of atrial fibrillation is permanent atrial fibrillation, which is ones who do not respond to any intervention, so that is something that we don't really know until we've done a procedure. So, permanent AF patients, we don't really know who they are until we do an intervention on them. But, of the two, paroxysmal and persistent atrial fibrillation patients, paroxysmals often have very high success rates with catheter ablation, up to 80%, or some people say more, but 70 to 80% or more success in atrial fibrillation. The persistent atrial fibrillation people, especially those with morbid obesity, or who have been in AFib for a long time, they don't have such high success rates. Their success rate with catheter ablation may be less than 50% or 40%, whereas in surgical cryomaze procedure, even those patients have very high success rates in excess of 80, 85%. So, catheter ablation is very useful, it's less invasive. It takes a longer time, but it's less invasive. You go in through a groin, whereas in cryomaze procedure, it's a little more invasive because you have to be on heart-lung machine through the groin, and you have a small incision between the ribs, on the right side, and you have to be in the hospital three to five days typically, but catheter ablation, you're in the hospital maybe a day or two. So, the idea of preventing clot formation in the left atrial appendage, and how to prevent that, one was to get blood thinners so the blood doesn't clot, but as I said, it's associated longterm with bleeding problems, so the idea was to fill that sack, and obliterate the space. So, WATCHMAN device is a little inverted umbrella, basically to obliterate the windsock deformity, but there's a foreign material sitting inside, so you have, typically the FDA guidelines say you have to take blood thinners for 45 days, until a smooth, inner lining forms on the WATCHMAN device, and the fabric of the WATCHMAN device is not exposed to blood anymore. After that, blood thinners can be stopped, and that has been shown to be equivalent to taking blood thinners. There's lower risk of bleeding after WATCHMAN device implantation, and it is, like I said, it has similar success rate in terms of longterm stroke rate, as taking blood thinners. It's approved for patients who cannot take blood thinners, or have contraindication or adverse reactions to blood thinners. While the WATCHMAN device sits inside the windsock, the left atrial appendage, and obliterates it, the atrial clip is literally just a clip that goes from outside, and pinches the atrial appendage shut, right at the base, so there's nothing sitting inside the heart, there's no foreign material inside the heart, and you don't have to take blood thinners because there's no foreign surface exposed to blood, and we can do it with a keyhole incision. Basically, it's not an incision, just three ports, and it's relatively straightforward and easily tolerated by people. Typical length of stay in the hospital is about a day or two, or at most, three days. The only problem with that procedure is people who've had previous heart surgery, they have scars around the heart, and those are not a candidate for left atrial appendage clip. The WATCHMAN device is actually a good option for those patients because you don't have to worry about the outside scar, you just go inside and deploy the WATCHMAN device. So, every device has its own strengths and weaknesses, and we can choose which one is best for which patient. And there's a rare type of patient who cannot take blood thinners at all. It's called cerebral amyloid. For those, again, WATCHMAN device would not be an option because during the procedure, you have to take blood thinners. People who have had previous heart surgery cannot have the clip, so WATCHMAN device is a good option for them. People who have had acute stroke because of atrial fibrillation, the neurology literature says that they're at high risk of having another stroke in the first four weeks after the first stroke. That is the time, again, where WATCHMAN device is a high risk because of blood thinners, whereas we can perform the clip procedure on those patients. If they're reasonably recovered, and reasonably good candidates after the first stroke, and it's not catastrophic, then we can prevent future problems by doing the clip procedure early after the stroke. So, those are some of the benefits. Plus, some people don't feel comfortable having something inside their heart. The risk of the WATCHMAN device include perforation of the heart, or the device getting dislodged and going outside, and they have to go across the septum, on the upper side, so they have to make a small hole to get to the left atrium. So, some people do not feel comfortable that is safe for them, whereas clip, we don't enter the heart, we don't stay, we don't make any holes inside the heart, so it can feel comfortable that that is a safer procedure. But, they both are very safe. Many people, they've had atrial fibrillation for a long time. Typically, the earlier you treat, the higher your success rate. People who have had atrial fibrillation for more than 10 years after a maze procedure, their results are not as good. They may be 80% or 70% success rate, but people who've developed giant left atria as a result of AFib for a long time, those people are not very good candidates for return of rhythm; they have so much substrate, so much tissue in the big, large left atrium, that you cannot make enough scar tissue, you cannot convert them into sinus rhythm. Plus, people with bad sleep apnea, they are associated with lower success rate. We don't know the exact mechanism of that, but we do know that that's the case. So, giant left atria, which is very big, upper chamber of the heart, and very longstanding atrial fibrillation, 20 years or so, their success rate is pretty minimal. We sit together, Dr. Chacko and I, the electrophysiologist and myself, and it doesn't mean literally we sit together, but we discuss patients.

Some people are clearly beneficial: 17:01

fibrillation, they're young, they're easily treated with catheter ablation, but more complex than simple patients we discuss together, and see what is the benefit of one versus the other, what do you think is the success rate, what are the complications, what technical challenges do you think you'll have if you do this approach, or what are the technical challenges if you do this approach? So, we customize every patient's disease based on their other co-morbidities and conditions, and then come up with a plan. So, sometimes I will do the cryomaze procedure, and if there's a problem later on, he can still go to the cath lab, and find a little spot, which was missed, and he can fix that spot, or he can do the catheter ablation. If it doesn't work, we haven't burned any bridges, I can come back, and do the surgical cryomaze procedure. The success of cryomaze is not affected by whether a person has failed a catheter ablation or not, it's asimilar. So, rather than one size fit all, we customize every patient's case based on their atrial fibrillation, the duration of atrial fibrillation, other health conditions, and what are the chances of success? The Holy Grail has been to find a way that'll cure 100% and have no complications. And as we know, nothing in life is for free, so we're always trying to find the best lesion set that will affect, and then there are newer blood thinners, which can reduce the risk of bleeding complications. The pharmaceutical industry has made a lot of stride in that regard, their newer blood thinners, which do not require the patient to undergo blood testing, but the success rate, and they have been associated with lower risk of stroke and less bleeding complications, some of them. But again, there are complications. There's always adverse effects of either the procedure or the drugs and medicines. Prevention is important. As I said, blood pressure, sleep apnea, weight reduction, diabetes, heart condition, those are all associated with atrial fibrillation, so if we can work on lowering the risk of these conditions in ourself. We know obesity is a big problem in our country, it's been growing, and if we can control those factors, I think we can hope to see a decrease in the incidence of AFib itself. I don't want patients to feel anxious that they have atrial fibrillation, and I don't want them to feel laissez faire, that it's not a big deal. Both of them can create problems. If they don't appreciate that they have AFib, and that they're at a high risk of having complications, then they may not be so compliant with the medications: the blood thinners or beta blockers slow down their heart, drugs that can clearly improve the outcomes. But, I don't want them to be so concerned that it's a death warrant on them, it's not. People have had it for a long number of years. As we identify each patient's medical history and chart, we can identify who are at high risk of stroke. It's something called the CHADS-VASc score. There's a lot of literature and studies being done that show which patients are at high risk of having complications, and the CHADS-VASc score depends on their other conditions, like congestive heart failure, diabetes, hypertension, previous risk of stroke, and we can identify those patients, and treat them earlier and faster. So, there are treatment options. It's not a condition that cannot be treated. We have, like I said, greater than 80, 90% freedom for atrial fibrillation, and then new technologies to reduce the risk of stroke, and even if they need blood thinners, there are better blood thinners now, so definitely we are much better off in treating atrial fibrillation now than we were 25, 30 years ago. But that, again, means that patients have to be aware of the condition and their risks, and be compliant with their medications, and follow up with their doctors. (upbeat music) - Thank you for listening to "Prescribed Listening" from the University of Toledo Medical Center. To learn more about the provider you heard on today's show, visit "Prescribed Listening" will be taking a few weeks off. Subscribe on Apple Podcasts or Spotify to get notified when we return.

Last Updated: 12/21/22