So welcome back, everyone, to part two of our programming basics. We've covered sensitivity, output, our pacing modes, and now we're going to dive into lower and upper rate programming. There are a few considerations here that we want to keep in mind. The first are our patient's underlying medical conditions. So let's think about this for a second. If a patient has, let's say, HOCUM, where we might not want them to pace at high rates because we could cause symptoms. That's something that we would need to keep in mind. If a patient has cardiomyopathy, or if a patient has any other condition that might affect their ability to tolerate faster pacing rates, we also want to keep that in mind. There are also other things that we want to consider. So for example, if a patient has sinus bradycardia, we don't want to set their pacing rate so low that they're not getting the pacing support that they need. That also plays into our reason for implant and understanding why the device was implanted and what our goals were for our backup pacing support. Activity level is very important to keep in mind our patient's age. And then we talked about briefly in interrogation basics, sleep mode, which is where if you have a patient, they need that backup pacing support, say, at 60 beats per minute because that's where they feel best during the day. But at night, they feel like their heart rate is just a little bit too fast and they can't sleep. You do have the option of turning on a sleep mode in most devices where you can lower their heart rate during sleeping hours so they don't have that faster heart rate in the evenings. Another feature that we haven't talked about before is one called rate drop response. This is a feature that is available in most manufacturers. And what it's designed to do is to let the patient's own intrinsic heart rate come in as much as possible. But what it's looking for are sudden drops in heart rate. So if you have a patient who is going along at 70 or 80 beats per minute, and all of a sudden their heart rate drops to 40, what this feature does is it paces them at a much faster rate for a short period of time to hopefully not only augment their heart rate, but also help augment their blood pressure through that faster heart rate, and then decreases that rate slowly over time. The most common instance for using that type of pacing mode is in our neurocardiogenic syncope patients where they're on their own for the most part, but sometimes have those sudden rate drops and they need that backup pacing support. Now that we've covered lower and upper rate, I want to touch on intervals for just a couple of seconds. I know that Dr. Allred spoke about these a lot, talked about PVARP, and AV delays, and TARP, and all of those good things. For this discussion, we're going to limit our talk to just AV delays. So there are two types of pacing intervals. There's a paced AV delay, and then there's a sensed AV delay. And I want you to think about these a little bit differently. So AV delays in a normal heart would be representative of your PR interval on a surface electrocardiogram. What we're trying to do with our pacing programming is mimic the normal heart's conduction as much as possible. So the reason that you have a paced AV delay and a sensed AV delay, and they might be different from each other. If you can imagine a sensed AV delay, it's going to more naturally mimic the heart's intrinsic conduction. So a P wave comes in intrinsically. We're wanting the device to time off that intrinsic P wave and then provide ventricular pacing support if it's needed once that interval times out. If we're artificially creating that P wave through atrial pacing, it takes longer to depolarize the right and the left atrium than it does for an intrinsic P wave. And for that reason, your paced AV delays are often a little bit longer than your sensed AV delays. So our normal programming out of the box for most devices would be, for example, a paced AV delay of 180 milliseconds and a sensed AV delay of 160 milliseconds or something very similar to that. Whenever you think about programming your AV delays, a few things I want you to keep in mind. The first is, does the patient have underlying normal conduction? And by that, I mean, is their AV node functioning appropriately? So if a patient only needs atrial pacing support, we want to make sure that we're limiting RV pacing for all the reasons that we've said before. We know that RV pacing can be detrimental because it causes increased atrial fibrillation burden and also can cause a patient to develop a cardiomyopathy. And so if you have a patient and you're convinced that they have normal AV conduction, you might program their AV delays to be a little bit longer. Or you might utilize a pacing mode that's specifically designed to limit RV pacing. Some more considerations are the type of device that's implanted. We've spoken briefly on his bundle pacing and left bundle pacing. We also have CRT devices or devices that are programmed to either maximize pacing support or minimize pacing support. So the type of device that you have implanted will also impact what your AV delays are that you choose to program on, device indication, and then our goals of pacing. So for every patient that sits in front of you, I want you to think about, does the patient need pacing support first and foremost? The answer may be no. If they do need pacing support, then are we primarily trying to support their atrium or their ventricle? And then based off of that answer, I want you to think about programming your AV delays to most naturally mimic a normal cardiac cycle. So what we're trying to do is make sure that we have adequate atrial filling, both passive and active, before ventricular contraction. And in order to do that, we need to make sure that our AV delays are programmed in a way that most likely mimics what the patient's normal conduction would be outside of any conduction system abnormalities. CRT patients are a unique group that require special attention and intentional programming. I want you to think about your CRT patients a little bit differently than your other patients that might have single or dual chamber pacing systems. Our CRT patients are those that we know have cardiomyopathies. And oftentimes, these devices were implanted with the sole intention of improving their symptoms of heart failure. So that's really important that as we speak with our patients, especially those who have CRT devices, we're investigating how they feel. How are they able to move around? Are they able to achieve their goals with activities of daily living or even exercise? I want you to look at your pacing percentages at every in-office or remote evaluation. And we've talked about how to do those a lot in our interrogation module. I also want you to look at intrinsic rhythm and AV delays at every in-clinic evaluation. As you're doing your sensing test and as you're doing your threshold test, I want you to evaluate what is this patient's normal conduction right now today because it changes over time. I also want you to keep in mind that just because a patient sitting in front of you has this conduction right now in this moment, it could very well change whenever they get up and walk down the hallway. So there's no one perfect way to program our CRT patients. But we do have ways that can indicate to us what is going to be most successful for this patient. And in order for our patients to receive benefit from their CRT therapy, it's our responsibility to make sure they're programmed optimally. And that's why I'm really hitting on this point right now hard. It's because these patients, like all of our device patients, are unique and special and we care about them all so much. But these patients specifically have come to us with symptoms. They haven't been able to do what they wanted to do because of shortness of breath or just limiting their activity because they can't move the way that they want to move. And we have a really, really powerful tool at our hands with this CRT therapy. And so I want you to just pay very close attention to what the patient is telling you, how they're programmed, and then evaluating might there be an opportunity to optimize this patient's programming so they receive full benefit from this therapy. One of the issues that we see in our CRT patients is suboptimal AV timing. There's been a lot of research done looking at CRT responders and CRT non-responders. So our CRT responders are patients that either improve a functional class with CRT therapy, they're able to improve their six-minute whole walk times with CRT therapy, or their EF improves with CRT therapy. That's the ultimate goal. Our CRT non-responders are patients where those things don't happen. They don't feel better. They can't walk any longer than they could before. And their EF doesn't improve with CRT therapy. One of the main reasons that patients don't respond to CRT therapy is this suboptimal AV timing. So either we have their AV delays programmed too long, or their intrinsic beats are coming in, and their own heart is beating out the device, or they're programmed too short, which doesn't allow for optimal filling time to optimize ventricular contraction. And so as we think about this, we want to make sure that we're optimizing our patients' AV timing as much as possible. A lot of devices now do have algorithms built in to do this automatically for us. I'm not going to speak to them all today, because each manufacturer is different in the algorithms that they have to promote CRT pacing. But I do want to encourage you to meet with your industry representatives, understand what those algorithms are for their devices. I also want you to understand who those algorithms would not apply to. So for example, if a patient has complete heart block, oftentimes a lot of the algorithms today aren't going to apply to those patients, because they're deciding timing based off of intrinsic RV signals. And so if a patient doesn't have intrinsic conduction, the device isn't able to use that information to decide optimal LV pacing timing. The other thing that we need to keep in mind is that AV timing changes over time. And so our patient's hearts change, our patient's conduction system changes. And interestingly, what often can happen is that with CRT, a patient is a responder or even a super responder, their heart physiologically changes. So instead of that kind of soccer ball shape, we get more of a heart. With our CRT pacing, which can affect our AV delays. And so just because a patient's EF has improved, I don't want you to take that for granted that everything's OK. For every patient that sits in front of you every single time with a CRT device, I want you to evaluate what their intrinsic AV conduction is, look at their programming, and then think about, should I change this based off the information that I have today? OK, so let's talk about CRT. There are different types of sensors located within the devices. There are several different types of sensors depending on device manufacturer or device type implanted. So the first is an accelerometer, where the device is able to sense motion within the chest cavity. So what it's mostly looking back is forward and back motion. So for example, if a patient is walking or running, an accelerometer is able to sense the movement of the chest cavity. So if a patient is walking or running, an accelerometer is going to be very well equipped to pick up that type of motion. But it may not be able to pick up motion when a patient is riding a stationary bike, for example, because there isn't really that forward and back motion with riding a stationary bike. Another type of sensor that devices can use is one where it can monitor the heart's contractility and can augment rate response based off of the heart rate compared to squeezing. That type of sensor is going to be much more accurate when it comes to activities like stationary bikes or even swimming, for example. Whenever you think about rate response and if you should program rate response on a patient, there are a few things to think about. The first is what is their histogram distribution like today? So if you remember, we talked about histograms and wanting to have that nice bell curve. So if you have a patient who has adequate heart rate excursion, there's probably really no need to turn on rate response for that patient. However, if you have a patient and their histograms are very flat or they're blunted, that may be the patient where you want to consider turning rate response on. When you think about turning rate response on, it's also important to keep in mind the patient's age, their activity level, and their underlying medical conditions, just like every other programming thing that we've mentioned today. The devices are very, very good at augmenting heart rate based off the information that they're given. There are those some patients who aren't adequately supported with out-of-the-box programming. And so for each manufacturer, you can change how sensitive the rate response is based off of their activity level. You can also change how fast their heart rate responds based off of their activity level. I'm not gonna go into those specific examples right now, because again, they are manufacturer-specific, but I do want you to know it's not just turning that rate response on. It's also evaluating a patient's response to that programming and seeing if they're adequately supported at that time from a heart rate standpoint. So a really good best practice is if you turn rate response on, have a patient do a few laps around the office and have them come back into your device exam room, throw the wand on them, see what their heart rate is and ask them how they feel. You can do that more than once. And hopefully you're gonna be able to walk out that day with a patient who feels confident that you've spent the time to get their programming adequate for them and that their device is able to provide adequate heart rate response to their activity level. A good encouragement for patients is to say, look, we're turning rate response on today. Sometimes it takes the device a little while to learn you and for you to learn how your body's gonna respond to that faster heart rate with activity. Give it a couple of weeks and call me and let me know how you're feeling. And then that way it gives the patients some realistic expectations that just a couple of laps around the office is probably not representative of their day-to-day life, but that you are committed to making further programming changes should they be symptomatic or not have the heart rate response that they were looking for when rate response was turned on. Okay, now that we've talked about sensing thresholds, our pacing modes, rates, intervals, and rate response, it's time to spend a little bit of time thinking through how we're going to tell our devices to detect and respond to atrial arrhythmias and ventricular arrhythmias. This is different from all the programming that we've talked about before because it's not actually going to affect how the device necessarily behaves, but it is going to affect how the device sees events and what it does with that information. So let's start with our atrial arrhythmias. So we know that we have our big buckets of atrial arrhythmias. We've got our atrial fibrillation, which is our most common atrial arrhythmia. We have atrial flutter. We have SVTs, and we also have sinus tigercardias that often can fall into these detections. So as we think about where we want to program these devices to sense and then what response we want these devices to have to that information, a few things to keep in mind. The first is does the patient have a history of atrial fibrillation or atrial flutter? If they do, then you might want to consider turning something like atrial therapies on where the device can actually initiate therapy, often in the form of faster pacing, to try to help terminate those atrial fibrillation or atrial flutter episodes. If a patient doesn't have a history of atrial fibrillation or atrial flutter, you may not want to turn those therapies on because you want to get that information, evaluate how long those episodes were going to last in the absence of intervention. That's a very physician-specific programming consideration and so one that I would encourage you to talk to your physicians about before making any changes to either therapy or detection. Another consideration is what is the patient's CHADS VASc score? This is very important, especially as we think about device recording and device alerting for these atrial arrhythmia episodes. So, for example, if a patient has a CHADS VASc score of 6, which is pretty high, we know that if atrial fibrillation was detected, their stroke risk would also be significantly affected because of their high CHADS VASc score. So, for those patients, I probably am going to have a much more aggressive atrial fibrillation detection window because I want to know about those episodes much faster. On the other hand, if a patient has a CHADS VASc score of 1 or even 2, guidelines would say we have some latitude there on whether or not those patients even need to be on anticoagulation and so you might choose to not have those episodes detected or especially alerted until those episodes meet a much longer duration. So, for example, if a patient has a very high CHADS VASc score, I would probably set their AFib detection at 30 minutes. If a patient has a lower CHADS VASc score, I might take that AFib detection out to 6, 12, or even 24 hours depending on physician preference and what they're going to do with that information. Another question to consider is, is the patient on oral anticoagulation or have they had a left atrial appendage occluder device placed? And the most important question is, what duration of episode would be considered actionable by your physicians? So, what I want you to keep in mind is that programming a device to detect an episode is important information for you because that determines how many episodes you need to review whenever a patient comes back into clinic for follow-up. So, if you have a patient with known AFib who has been on anticoagulation and is appropriately cared for, if you tell that device, I want you to record every AFib episode that's 30 minutes or more, you're going to have a lot of information to review when that patient comes into clinic or when you receive that remote transmission. On the other hand, if that patient is appropriately anticoagulated, has a known history of AFib, a more reasonable approach might be to say, okay, I only want to know about episodes that are at least 24 hours in duration because that might indicate a change in a patient's pattern of atrial fibrillation which might necessitate action. So again, these are really important conversations for you to have with your physicians because you want to get the information that you need, but you also don't want to get the information that you don't need that is not going to have any impact at all on a patient's care or their outcome. So, let's switch over to ventricular arrhythmia detection and ventricular arrhythmia therapy. A couple of comments here. Ventricular arrhythmia detection is going to occur for both Brady and Tachy devices, so your pacemakers and your ICDs are going to be able to detect ventricular arrhythmias. Only your ICDs are going to deliver a ventricular arrhythmia therapy, which makes sense to us. I think sometimes that we forget that our pacemakers are also looking for these arrhythmias and we have control over what we're seeing here and how much information we want to receive. So, same type of concept. If you have a pacemaker patient, and we're going to park here on pacemakers for just a second, those same considerations for atrial arrhythmia detection apply to ventricular arrhythmia detection. I want you to think about what arrhythmia am I going to take action on, or is my physician going to take action on? Out-of-the-box programming for pacemakers, in particular, are very, very, very aggressive for ventricular arrhythmia detection. Oftentimes, they can be set at 150 beats per minute for four beats. There are very few physicians and very few patients for which that would be an actionable event that you would need to take clinical action on for that patient. So, my encouragement to you is to speak with your physicians, understand what rate and what duration do you want to see for your Brady patients for ventricular arrhythmia detection. Again, this gets to the heart of device and remote follow-up and that we need for it to be efficient and effective, which means we don't need to be looking at hundreds of episodes that we're not going to do anything about. I want you to think about arrhythmia detection as needles and haystacks. So, if we have a lot of episodes, say you come into a patient follow-up and there's 80 episodes that you have to adjudicate. One of those in there might be clinically actionable, but I can tell you from experience, after you flip through 20 of them and you didn't see anything that was actionable, the natural inclination is to say, well, the rest of these should probably be okay too. We have to look at every single one, which is the reason for my encouragement to say only program your detection for episodes that you're actually going to take clinical action on or that you might be curious about because it might affect your patient's care. Whenever we think about ventricular arrhythmia therapies, this again is going to be very specific to our defibrillator patients. Our goals for therapy, we want to reduce shocks whenever possible. We know that shocks are painful. We know that we can terminate a lot of ventricular arrhythmias without the need for shock therapy. We also want to make sure that we're programming our devices based off of the patient's disease state and their indications, and that we know that clinical evidence for specific ICD device programming is growing. What do we mean by that? There have been a lot of studies that have come out that have shown that we are able to successfully terminate ventricular arrhythmias, even very fast ventricular arrhythmias, with anti-tachycardia pacing, which is a painless therapy for patients and allows them to avoid shocks within their device. We want to avoid shocks for a few reasons. Not only are they painful, but they also can cause pretty significant emotional distress for our patients, and that's something that we can never take too seriously. Our patients are already scared, so we've told them that they're at risk for dying suddenly. We've told them that we're putting this defibrillator inside of their body to help protect them from that sudden death. I want you to put yourself in their shoes for a second. That's a terrifying scenario, right? To be told your heart could short-circuit on you and you could have a cardiac arrest, and we're giving you this device to try to mitigate those risks. Patients want to know, am I going to get shocked? Is it ever going to happen? And if it does, what does that mean for me? And so any chance that we get to terminate ventricular arrhythmias with painless therapy, where a patient may not even ever know it happened, is ideal for that patient as opposed to getting a shock. In North Carolina, for example, if a patient receives an ICD shock, their driving is limited for several months, and so that also plays a big role in how we program these devices, how we communicate that with our patients, and just the huge importance that we have in managing our patients collaboratively with our physician colleagues and making sure that we're wrapping our patients into this care and always keeping them front of mind whenever we're choosing device programming. So here are some questions to think about for our ICD patients. So is this patient a primary or a secondary prevention patient, and what do I mean by that? So primary prevention means that a patient has never had a cardiac arrest. They have a cardiomyopathy. We know because of studies that they're at increased risk for sudden cardiac death, and we're putting this device in to help mitigate that risk should an event ever occur. We also know that a lot of patients that we implant for primary prevention never receive device therapy, which is a good thing, but it's their safety net. It's there for them should they ever need it. Our secondary prevention patients, on the other hand, are patients that have had a cardiac arrest in the past, and so we're putting this device in in case they have another event. These patients are often much more receptive, honestly, to the ICD being implanted because they did have an event, and they know what happened to them, and they don't ever want to go through that again. Our primary prevention patients, you're selling an insurance policy, if you will. Our secondary prevention patients, they had that wreck. They want to make sure that their car is in good shape so that we don't have that happen to them again. Another consideration is what is the patient's age? This is really important to consider as you're programming your VT and your VF zones for detection and for therapy. So if you have younger device patients that are very active, you may want to have a higher VT and VF zone so they don't receive inappropriate therapy for normal intrinsic heart rates that could have occurred with activity. That also plays into this next point, what is what is the patient's activity level? Are they receiving adequate pacing support? Is the patient taking medications that might affect their sinus heart rate? Flip side of that, is the patient taking medications that might affect their ventricular tachycardia rate? So if a patient has a known ventricular arrhythmia or they were put in for secondary prevention and we've chosen to put them on antiarrhythmic drug therapy, it's very important to understand what medication they were placed on and what effect that medication has on their ventricular tachycardia cycle lengths because you might need to lower their detection zones at that point to make sure that we're not missing any ventricular arrhythmias. We don't really do EP studies anymore. That was done a lot in the past. We've kind of moved away from that, but if a patient did have an EP study done, an important question to ask is what were we able to induce? What was that cycle length? And then making sure that we have our device programmed to treat those arrhythmias as well. A really big question to consider is does the patient have concomitant supraventricular arrhythmias? So does the patient not only at risk for ventricular arrhythmias, but do they also have atrial arrhythmias? I want you to think about our AFib patients who might have rapid ventricular responses. So oftentimes our AFib patients can have ventricular rates into the 160s, 170s, 180s. So we want to be sure as we're looking at our device interrogations and we're looking at the information that's provided from our device visits, that we understand what the ventricular response to our AFib episodes are, that we're adequately controlling that ventricular rate, and that we have our ICD tachy therapies programmed to make sure that we're not treating atrial arrhythmias with a rapid ventricular response. So there is kind of this elephant in the room of inappropriate shock therapy, and this is a big deal for our patients, and it happens for a few different reasons. A really good example is that patient with AFib at RVR where they got shocked for that arrhythmia and did not need to be shocked. Data has shown that inappropriate shocks occur in 20 to 30 percent of the patients over the lifetime of the device. That's a really big number, and it's a really scary number. It's one thing to call a patient and say, I know you got shocked, but really good news, that device just saved your life. It's a much more difficult conversation to call a patient and say, I know you got shocked and your device went off for the wrong reason. And so we want to keep this in mind always as we're thinking about device programming, as we're thinking about which discriminators we program on in our devices, ventricular rate detections, and which therapies we're programming on. I'm not going to go into those discriminators or other things here. Again, they're very manufacturer-specific. I do want to encourage you to get with your device representatives. Make sure that you understand how the discriminators with each manufacturer work. Make sure you understand how fast those discriminators will be applied to. So at some point there's a rate cutoff that says, okay, we're like, we're blinded at this point. It's a fast, this heart rate is fast enough. We're delivering therapy. I don't hear what the discriminators show. So make sure that you understand that and also understand what would make those discriminators not work besides rate. There are certain situations where the device says, you know what, I think this patient is in a life-threatening arrhythmia. I'm going to treat this rhythm regardless of what any discriminator would say. And the device is always going to err on the patient's safety side. It's always going to deliver therapy if there's a question, and we want that to be true because the worst thing that could happen is that a patient did not receive therapy that they needed from a device. So why is avoiding shock so important? We've talked about this a little bit. The impact on a patient quality of life is huge. So the light blue shaded boxes are patients that received an ICD shock. The dark blue shaded boxes are patients who did not receive a shock. And you can see that ICD shocks, whether or not they were appropriate or inappropriate, affects a patient's perception of their health, their physical function, their emotional and social function, and also their self-rated health. I want you to catch what I said though. This is if they were appropriate or if they were inappropriate shocks. Either one has negative effects on our patients. And so anything that we can do as device clinicians to reassure patients, you have a device implanted that's meant to save your life. It's meant to be your safety net. It's there if you need it and we're gonna hope you never do. But all of those conversations every time they come into the office are very important to have just so that the patients are validated that yes we are taking this as seriously as they are. They do have an important device implanted and we're going to make sure they're programmed optimally to avoid any shocks as long as we can help it. There's also economic impact for our patients who receive ICD shocks. You can imagine that patients who receive shocks are scared. A lot of these patients end up in the emergency room. Most of our clinics have shock plans. If your clinic doesn't have a shock plan, I want to encourage you to develop one. At my institution where I previously worked, we actually put them on large magnets that a patient could have on their refrigerator and we also made them into wallet cards and a few reasons for that. We talk about a shock plan every time that we see our patients in the office and they forget because we only see patients once a year in the office perhaps. And so having that shock plan at home for them can be really valuable so they know what to do in the event they got shocked. Our goal is to keep them out of the hospital. So a really good shock plan is to say if you get shocked once and you're feeling okay, that's great. Call the office and let us know. Send us a remote transmission. We're gonna review it. We're gonna call you back. If you get shocked after hours and you're feeling okay, same plan. Just give us a call the next business day. If you get shocked more than once or if you get shocked once and you don't feel okay, so you're having chest pain, shortness of breath, dizziness, that's when you call 9-1-1. It's important to tell the patients not to drive themselves to the hospital, not to have a family member drive them to the hospital. If they've gotten more than one shock or if they've gotten one shock and they're not feeling okay, the only appropriate course of action in that situation is for them to call 9-1-1. So let's take a quick break here and just think about this question. So according to clinical evidence, why is it important to reduce inappropriate shocks? So shock reduction can significantly improve patient quality of life and ICD acceptance. Strategies to minimize shocks with ATP therapy and reduce overall ventricular arrhythmia may further improve survival in ICD patients. Or shock reduction has no economic impact on health care utilization. We've talked about the economic impact, so we know that one's not true, but A and B here are absolutely true. We know that shock reduction can significantly improve our patients quality of life and we also know that minimizing shocks may also further improve survival in our ICD patients. So why do patients get shocked? So 65% of shocks are treating true arrhythmias and in the average primary prevention patient, 35% of shocks are inappropriate. So what are those things coming from? So 3% of those therapies are from non-sustained ventricular tachycardias and that's where it's important as we think about our detection and how long we want a patient to be in an arrhythmia before they receive therapy comes in. About 20% of shocks come from SVTs, so supraventricular arrhythmias, and wrapped into this bucket are things like our atrial fibrillations, our atrial flutters, and our SVTs. So all of those are grouped in here together. These are the ones that we have a really big chance of being able to avoid with really good device programming. And then 12% of shocks come from over-sensing or artifact and a lot of these are from T-wave over-sensing and we've spoken about that a lot when we talked about sensing and we've talked about our programming to avoid seeing in signals that aren't R-waves and aren't P-waves. This is an example of T-wave over-sensing and I want you to look at the scatter plot first. So let's orient ourselves to this strip. So on the left hand side we have our intervals in milliseconds. I want you to remember the lower the number of intervals the faster the rate is. We also have our lines here for programming and on the right hand side here you can see that we have a VT zone programmed at 370 milliseconds, a VF zone programmed at 300 milliseconds, and a fast VT zone programmed at 260 milliseconds. And you can see those visually represented there by those three horizontal lines. We have time moving across the screen. On the bottom strip we actually have our electrograms. So we have our RV tip to RV ring electrogram, that's our bipolar electrogram, and then we have our can to RV coil electrogram which is going to mostly mimic our surface electrocardiogram. So what we can see at the beginning of this strip is this railroad pattern to those V to V intervals. So our V to V intervals are represented by those purple diamonds and you can see at the beginning of this strip we've almost got them on top of each other and that's where the detection occurs. So let's look at that blown up down here at the bottom. So you can see the device is telling you that we had a purple V sense interval and then we had yellow tacky sense intervals. So the TS's means the device is telling you this rate is in my VT zone and I am going to start counting these intervals to see if I need to deliver therapy or not. However, whenever we look at our intercardiac electrograms we can see that the device is seeing the patient's T wave. So you can see that initial deflection there is the patient's R wave with every single cardiac complex the device is also seeing the patient's T wave. That's when we get that railroad track pattern. This is what we always want to avoid because as you can see in this example back up on the scatterplot the device declared an episode of VT met so it delivered a burst of ATP, continued to have over sensing, another burst of ATP, continued to have over sensing, and then the patient actually received a high voltage shock for this. So this was an inappropriate therapy because of T wave over sensing and this is what we always always always want to avoid. So how do the devices try to get around this? So all manufacturers have a T wave discriminator algorithm that tries to avoid seeing the T waves. Most devices and most manufacturers work by saying we're going to sense our R wave, we're going to set a threshold off of that based off of our sensing level. So let's say for example our R wave measured 8 millivolts. So most manufacturers at this point will say let's go 50% of our R wave so we're going to start at 4 millivolts and then we're going to slowly decay our sensing down until we get to our next interval. And the reason that the devices do that is because with ICDs you can't necessarily have a fixed sensing programming and that's because we're going to miss our smaller sensing signals like ventricular fibrillation. And remember we said the device is always going to err on the side of patient safety and so we need to decay our sensing down so that should a patient go into ventricular fibrillation the device is set up and is equipped to see those signals. So for that reason the devices have this kind of dynamic sensing for our ICD patients especially when it comes to ventricular sensing. So again we're going to measure our R wave, we're going to set a threshold off of that and then slowly decay our sensing down until we see the next signal. Now in this example the T wave is being sensed which is where we would probably need to say okay we either need to increase our ratio here we don't start so low or we need to delay our slope so that we can avoid seeing those T waves. This is another example of T wave oversensing where you can see at the top here we've got our RV tip to RV ring and underneath we have our RV coil to SVC. And you can see pretty clearly here that we're oversensing every single T wave that occurs following each R wave. Interestingly the algorithm here recognized that and so classified it down at the bottom as T wave oversensing. One option to address sensing issues especially if we're having T wave oversensing or other myo potential oversensing is to change our RV programming. So with most of our RV ICD leads we have a couple of options for sensing. We can have true bipolar which is where we're sensing RV tip to RV ring or we can have what's called integrated bipolar sensing which is where we have RV tip to RV coil. And so oftentimes if you're having trouble avoiding T wave oversensing with one of these configurations you can change your sensing configuration and that will resolve the problem. Very very important to note never ever ever change RV sensing especially in a defibrillator patient without reviewing the information with your electrophysiologist. For some patients this is completely inappropriate to do and for some patients this could cause really big problems. Historically if we had to change RV sensing vectors we would take patients back to the lab and do speefib, do DFT testing, make sure that the device could still see those sensing signals adequately. That's not done as often now but still very important to have electrophysiology input before changing any RV sensing especially in our defibrillator patients. We're gonna finish up here by talking about remote alert programming for our Tachy and our Brady patients. So these are going to be our pacemakers and our defibrillators and this programming is located within the device. So what I want you to think about is how do you want to be notified about changes that the device sees either from a device integrity standpoint or from an arrhythmia standpoint. And I also want you to think about what do I want to be notified about and what is going to clinically impact this patient's care. So as we think about our lead alerts if you remember from our interrogation talk we talked about those guardrails that are set up within the device. So oftentimes nominally out of the box those guard rails are set at 200 to 2,000 ohms. But we also talked about how there can be wide swings and fluctuations for impedances that might be clinically actionable but will not exceed those guardrails. So if you have a patient that you're concerned about you can always change your lead impedance alerts to narrow those guardrails so that you're being notified more frequently or earlier about a potential lead problem. Another lead alert the device can send to us are things to do with sensing and thresholds. So you can be notified for example if your P waves or if your R waves exceed the guardrails that you have set up there for your notifications. You can also be notified if your thresholds exceed your guardrails for notifications. So every time a patient's in front of you I want you to think about where is the patient today and what would I want to know about if something happened in the next year before I see this patient again. And then set your lead alerts to mimic those same criteria. Our device functionality alerts are going to be things like ERI for our battery voltage patients. One thing that's really important to consider is at which point would you like to put a patient on intensified follow-up for their battery. So some clinics choose to put patients on intensified follow-up at six months. We wouldn't necessarily get an alert that a patient is six months to elect a replacement indicator. But what we would be able to see is on a routine remote interrogation that they're nearing ERI and so we might want to do remote follow-up more frequently to be sure that we are able to adequately acknowledge that alert and get that patient set up for gen change before they started having any clinical issues. This is going to be mostly appropriate whenever we're thinking about our manual send pacemaker patients. Most wireless devices now you don't have to worry about that as long as your patient is connecting and you're monitoring your disconnected monitor status. We've talked about our atrial fibrillation alerts some. What I want you to keep in mind for those and also our ventricular high-rate alerts is that you control what you're notified about through the device. We can change some things on the remote websites but notification for these events starts at the device and so the take-home message here is to always think about what am I going to clinically do something about, what does my physician want to know about, and what's going to impact this patient's care. And so I want to encourage you to make sure that you have programmed on the data that's going to matter for your patient's care but that we're not getting any extraneous EGMs that aren't clinically actionable and that aren't going to provide value when caring for the patient. The last bucket here to talk about our heart failure alerts. Heart failure is becoming more and more of a talking point for a lot of our clinics. We're invested in this information. We know that we can act on this information and prevent hospitalizations for our heart failure patients and so again I just want you to think about what do I want to know about, what am I going to do something about. And so for example if you have an ICD patient who was implanted for brugada or long QT syndrome, it would not be appropriate to program your heart failure alerts on for those patients because they don't have a history of heart failure. However, your CRT patients, all of those patients are probably very appropriate to have your heart failure alerts programmed on for. So the take-home message for all of this remote alert programming again is to say what am I going to do something about, what is gonna be clinically actionable for this patient. And all of those things are done in conjunction with our EP physicians. Here are the references used in this module. Thank you so much for participating in this module. If you have any questions at all please reach out to academy at medaxium.com

programming considerations

lower rate programming

upper rate programming

implantable devices

pacemakers

defibrillators

patient conditions

programming features

inappropriate shocks