Welcome, everyone, to Interrogation Basics. My name is Amber Seiler, a nurse practitioner with CV Remote Solutions, and I'm excited to share this information with you today. These are my disclosures. So for today's module on interrogation, these are going to be our learning objectives. The first is learn how to conduct a follow-up for a device patient using a structured evaluation method. The second is evaluating arrhythmias and respond to alerts and trends. And the third is interpreting intracardiac electrograms. Because there's a lot of data to cover here, we're going to split this into two different sections, but these will be our objectives for both of the sessions. So as we think about structured device follow-up, I always like to start at the very, very beginning. My expectation is that you may be new to devices or exploring if this is something that you would like to get into further. And so it's really important to feel confident with what you're doing whenever you're in front of a patient. We have two ways of monitoring patients in clinic, which are when patients come to see us in the office and we actually interrogate those devices with a programmer, and also remotely, where information is transmitted from the patient's home to a remote website, where we're able to obtain that same information but without the patient in front of us. I wanted to spend just a few minutes here speaking to the importance of understanding programmer functionality. Each manufacturer has their own programmer, and they're all just a little bit different and have nuances that are really important to note and to be familiar with. Understanding each of those and diving into those is outside of the scope of this module, but a few things that I want you to make sure that you reach out to your manufacturer representatives and know how to use are, one, the power source, so making sure that you know how to turn the programmers on, making sure that you know how to save information from that programmer session. The second one is changing programmer paper. There's nothing worse than having a patient in front of you and running out of paper and needing to figure that out on the fly, so that's really important. And the third one is emergency pacing functionality. It's very, very, very rare that we get into situations where you would need to employ this emergency function, but it's really important to know how to do that should those situations arise. So again, these are things that it's important just to put a programmer in front of you, practice without a live patient there, understand how to turn the programmer on, change the paper, know where your emergency buttons are, and then that way, when you're ready to interrogate a patient, you're very confident in how that programmer works and where all of those key features are located. Teaching clinicians how to interrogate devices has been done for decades now, and one of the most common ways to teach device follow-up is a method called PBL-STOP, and that's the method that we're gonna walk through today. It's incredibly structured. It allows you to have a systematic approach to device follow-up where we make sure we don't miss any information, everything is looked at, and that you're doing it in a way that makes sense in your head, that you can replicate regardless of what patient is sitting in front of you or which device manufacturer that patient has implanted. And so as we think about PBL-STOP, the items that compromise this follow-up are P, which is presenting rhythm, rate, and percent pacing, the B stands for battery status, L is lead evaluation, S is sensing, T is thresholds, O is observations, and then P is programming. So for this module, with interrogation of devices, we're gonna focus on all except for the programming. A module following this will really focus on programming, what options we have there, and all of the ways that we can change patients' programming through their device. But for today, with our interrogation module, we're gonna focus on these first few and leave programming off, and we'll cover that in the next module. So we're gonna walk through each of these individually, taking some time to make sure that you understand the components of each of these pieces of the device follow-up. So the first, again, is P, so our presenting rhythm, rate, and percent pacing. There are some best practices when looking at presenting rhythm. The first, as you're learning devices, is to always hook the patients up to their surface electrocardiogram on the programmer. This is incredibly important because what the device sees is not what you're used to seeing. So if you've come from the hospital or from the office or from ambulatory monitoring, we're used to looking at electrograms that are seen from the body surface. The device sees things from inside of the heart, which is a very different approach. And so having that surface electrogram hooked up gives you a point of reference and is a best practice as you're learning to interrogate devices and make sure that you can verify that you understand what you're looking at for each of these patients. There was an ECG module previously that was reviewed that had best practices with things like lead placement, making sure that your patient is positioned correctly. All of those things still apply as you're hooking patients up to the programmer for a surface electrocardiogram. The second thing that's really important is understanding milliseconds to beats per minute conversion. This was also reviewed previously, but is incredibly important because devices don't typically relay information to us in beats per minute. Typically we get milliseconds. And so we have to have a frame of reference for what those conversions are, or to be able to do that quickly on our phones in the calculator if we don't have that memorized. The other big takeaway when looking at presenting rhythm is to verify that the rhythm matches what the device is telling you it's seeing. And we're gonna spend some time here looking at some examples to make sure that we understand that the external surface electrogram matches what the device is telling us that it's looking at. So the first thing that we need to keep in mind is that we need to remember what the device is seeing. This is very different from a surface electrogram and that we are actually seeing what the device is viewing from the lead tip. And Dr. Allred earlier reviewed things like unipolar and bipolar leads and what that sensing reflects and is representative of. And so as we go through these examples, I want you to keep that in mind and also the importance of understanding the surface electrogram and how those things correlate to what we're seeing from our intracardiac electrograms. So this is an example of a device with a presenting rhythm. And we're gonna take just a little bit of time to walk through this example. So if we look at the left-hand side of the screen, you can see the device has labeled for us what the EGMs are. So this first EGM one is our A tip to our A ring. And if you remember the lead talk from earlier, that is a bipolar electrogram. The second one is CAN to RV coil. So we're talking about the RV coil that's in the right ventricle all the way back up to the device CAN in the chest. And so that's gonna be more of a unipolar electrogram, but this is also very representative of a surface electrogram because of the huge vector that we're looking at with this example. The third EGM is LV tip to RV coils. That's gonna be our left ventricular tip to the right ventricular coil. And then we also have a leadless ECG, which is our CAN to the SVC coil, which is again, mostly representative of a surface electrogram because of the vector that's being captured here. Underneath that are our marker channels. So we have our A to A intervals. Again, this is why milliseconds is important because it's gonna tell us what this rate is in milliseconds. The next line is our markers. So this is telling us what the device is seeing. Every time that you're looking at a rhythm strip, I want to encourage you to look at the markers. We could look at the top piece of this and ignore the intervals in the markers and understand what rhythm this is, but we don't know how the device is interpreting that rhythm. And so it's really important to make sure that our marker channels are aligning with the information that we're seeing on the intracardiac electrograms. And then underneath that is our V to V intervals, again, in milliseconds. So my goal here is to just get you really well acquainted with the presentation of rhythms, how the device is gonna give you this information, and then how we can interpret these electrograms. So if we think about our A tip to A ring, so our EGM1, so that's gonna be our atrial contractions. So those on a surface electrogram are gonna correlate to our P waves. Our EGM2 on this example is gonna be most representative of our RV contraction, and that is gonna correlate to our QRS complex on our surface electrograms. And so we can track this down. So we can see that every A sense has an atrial deflection that's represented on the A tip to A ring electrogram. And then we can see that every by V pace has a deflection that's represented on our ventricular electrograms. So this device, what we can learn from this is that it's a CRT device. And you'll remember from Dr. Allred's talk earlier, that's a cardiac resynchronization therapy device where we have three leads, one in the right atrium, one in the right ventricle and one in the left ventricle. And then we can also tell from this tracing that we are A sensing. So this is a sinus rate and the device is by V pacing. And so this on a documentation standpoint would be written as A sense slash by V pace at a rate of 670 milliseconds or that conversion to beats per minute. So let's look at another example because these can be a little bit confusing as we look through these and just get really well acquainted with all of the information that's being presented to us with these strips. So in this example, again, we've got A tip to A ring at the top. So that's gonna be our atrial activity. The second one is RV tip to RV ring. So that's our ventricular activity. We have our A to A intervals again in milliseconds, our marker channel, which is what the device is telling us that it's seeing. And then our V to V interval again in milliseconds. So I'm gonna give you a second to look at this and think for yourself, what do you think this rhythm is? It's a little bit of a trick question, but not quite so much. So if we think about our atrial activity, it's a few observations. One, there's not a one-to-one correlation between our atrial activity and our ventricular activity. The second observation that I would see pretty easily is that our atrial activity is very regular. So if we look at our intervals, it's 200 to 210 milliseconds consistently. So that's a very regular atrial rhythm. The next thing that we see is that we're not V sensing. So we're V pacing. So, and we're V pacing at a rate of 60 beats per minute, which can tell us a few things. One, the patient's rate could just be set for a lower rate of 60 beats per minute. The patient could be inactive at this time. So there's a lot of things that we can gain from this. We also know that the patient's intrinsic ventricular rhythm is not faster than 60 beats per minute because they are pacing. So how would you interpret this rhythm? I would document this as atrial flutter with V pacing at 60 beats per minute. The reason I say atrial flutter is because the atrial rate is fast. It's 200 milliseconds and it's regular. And so this is an atrial flutter with V pacing. Let's do another example. So this is a different vendor. This is an Abbott device. And this is why it's really important to look at these things across all vendors. Sometimes I think the tendency is to get fixated on one and say, okay, let's do that one all the time. But it's important to be able to interpret these devices no matter what manufacturer the patient has implanted. And essentially they're all the same. It's just being able to locate the information and understanding where it's coming from. So with Medtronic where those indicators of what the EGMs were and the marker channels were over on the left-hand side, Abbott just places them at the top. So our first EGM here is our V unipolar tip. So if you remember unipolar is a much larger signal and that explains why we can see the T wave on that strip. The second EGM is our V sense amplitude EGM. And that's gonna be more of a bipolar signal. And then the third one is a discrimination auto gain and that's gonna be programmable. And we don't know exactly what that is on this device because we don't have that programming in front of us. The fourth line there is our marker channels much like the other EGMs that we've seen. And then below that is our intervals in milliseconds again. So what we can learn from this device is a few things. One, it's either a single chamber device or the device has been programmed to just pace in the ventricle and sense in the ventricle because we don't have any atrial information either on the marker channel or through an EGM. The second thing that we can learn here is that the ventricular rate's a little bit irregular. So we kind of vary from 832 to 875 milliseconds. So not a lot of irregularity, but some. The other thing that we can see is that the patient's intrinsic rate must be faster than their lower programmed rate because they're V sensing. And so if you remember from the previous device indication talks, in order for a patient to pace, their intrinsic rate must be lower than their program base rate. And so we know that this patient does have an intrinsic rhythm and that at this rate, they don't require pacing support. Let's look at one final example of EGMs. So this is a completely different device, but it's one that's being implanted more often. So this is a Boston Scientific Sub-Q ICD. The thing to remember about Boston Sub-Q ICDs, and there are other vendors who are coming out with this technology as well, is that there are no leads in the heart for these devices. And so this is going to be much more similar to your surface electrocardiogram. The cane is normally implanted on the left side of the body under the armpit, and then the lead is tunneled across the body and up the sternum. And so you're getting a vector that's very much a surface electrocardiogram whenever we're looking at these interpretations. The other thing that you'll notice is that our marker channels are a little bit simpler and less complicated, mostly because these devices aren't designed to pace, they're only designed to sense. But they do have some things like noise algorithms. It'll tell you if the device is seeing it as a tacky episode, those types of things. But what we can see here is that this is a V-sense event. We're not gonna get any atrial activity because again, there are no leads inside of the heart, and this is just a Sub-Q ICD. We can also see that it's a fairly regular rhythm, probably sinus rhythm. There's some P waves that we can make out there. The other thing that's important to note about this is that these devices don't provide you with intervals, which is okay because they do give you the markers, much like the surface electrograms that you're used to looking at to count those out. Okay, so now that we've looked at some samples of presenting rhythms, the other thing that I wanted to talk about was evaluating percent pacing. So when we think about pacing, there's four phases of pacing. And it's important to think about pacing in this way, and it's important to evaluate your patients in this way. So our four options for pacing for dual-chamber devices or CRT devices, we can have A-sense, B-sense, which essentially is sinus rhythm. We can also have a pace B-sense, which is where the atrial rate needs some backup pacing support, but the patient has intrinsic ventricular conduction. We can have A-sense, B-pacing, which is where our sinus node is functioning appropriately, but we've got heart block and so need B-pacing support. And then the last phase of pacing is A-pace, B-pace, where we need both atrial and ventricular pacing support. The reason that I want you to really evaluate your patients this way, and as you're looking at device interrogations, think about the four phases of pacing is because it gives you clues as to why the patient was implanted, if their device is acting appropriately and providing the pacing support that they need based off of their implant indication. A few things also to consider when evaluating percent pacing. We've talked about patient history a little bit here. So if a patient was implanted, for example, for sinus node dysfunction, I would expect that they would have mostly A-pace, B-sense, because we know their sinus node isn't functioning appropriately, and that should be where their backup pacing is needed. However, if a patient was implanted for sinus node dysfunction, and they come to see you, and you notice that they have a high percentage of ventricular pacing, that should be a red flag to say, is there any programming that we can do to limit ventricular pacing, or has their conduction system deteriorated that now they require ventricular pacing as well as atrial pacing support? The other thing to keep in mind with patient history is their age. So understanding our patient and their activity level, what their goals are for their activity level, making sure that they're able to achieve a heart rate that supports those goals. Those things are also really important to keep in mind. Medical therapy and what medications they're on play a big role in percent pacing and what is going to be required for them for backup pacing needs. So for example, if a patient has paroxysmal atrial fibrillation, and they're put on antiarrhythmic drugs or some sort of rate controlling medications that might increase their need for pacing support, which may make you want to consider things like rate response. Again, evaluating to be sure that our patients are getting what they need from the devices they have implanted based off of their current conditions. This is one of the reasons it's really important as a patient comes to see us in the office to do a really good history, understand what their activities are, understand if they're having limitations in those activities, and taking that time to make sure that their device is programmed optimally to support their lifestyle and their needs. Another question to ask yourself is, is AV block present or not? And we're going to get into that as we look at sensing and how to evaluate that. If AV block is present, that's going to necessitate some ventricular pacing support. If it's not present, again, we shouldn't have any, and so let's see if we can limit that ventricular pacing. If AV conduction is present, should we consider algorithms to minimize RV pacing, which is what we just talked about? And then importantly, if a patient has a cardiac resynchronization therapy device, should we consider algorithms to maximize CRT pacing? So as you're looking at percent pacing, both atrial pacing and ventricular pacing, I just want to encourage you to keep all of these things in mind as you're looking at the patient in front of you. There is no one right way to program a patient. Our patients aren't widgets, and so making sure that we take into account their specific needs and wishes for their lifestyle and activity levels are really important as we think about programming these devices. Let's talk about programming modes and how we know how a patient is programmed to pace. So this is going to be true for pacemakers and defibrillators, and it's going to apply to single chamber, dual chamber, or CRT devices. So as you look at program pacing modes, so for example, you might pull up a patient and they have their pacing mode is programmed to DDDR, well what in the world does that mean? So that first letter is going to be representative of what chamber is being paced. So if the device is programmed DDDR, that means that dual chambers are being paced, so we're pacing both the atrium and the ventricle. Now it doesn't mean necessarily that a patient is going to have 100% atrial or ventricular pacing, it's just saying that if a patient needs that pacing support, the device is programmed to pace in both the atrium and the ventricle to provide that pacing support. Another example, if a patient is programmed AAIR or VVIR, that first letter, that first chamber paced, is either going to be the atrium or the ventricle depending on how you have that device programmed. Now that second letter is also very important, and that's going to be which chamber is being sensed. So in our first example of DDDR, that means that we're pacing both the atrium and the ventricle, and we're also sensing both the atrium and the ventricle. Same thing for VVIR or AAIR, we're going to pace and sense either just the atrium or just the ventricle. The most common pacing modes have the same letters in both that first and second column of the pacing code. There are special situations where you may have a situation where you're pacing both chambers, but you only want to sense one chamber, either because you know that a patient has sensing issues or because of a different need within that patient. But what's really important to remember is to know what you're looking at as you're looking at how a patient is programmed. So again, that first pacemaker code is going to be which chamber is being paced. The second one is which chamber is being sensed. That third letter is going to be our response to sensing. So the most common letters that are in that third column are going to be I and D. So D means that we can either trigger off of a sensed episode or we can inhibit off of a sensed episode. So in our example of DDIR, we're going to pace both the atrium and the ventricle. We're also going to sense both the atrium and the ventricle. Our response to sensing is going to be to inhibit pacing. If we see either an atrial or a ventricular intrinsic event, then that means we're going to inhibit pacing in our DDIR example. The other thing that can happen with that response to sensing is that we can actually trigger a pacing response. And so this is often happening whenever we have patients who need both atrial and ventricular pacing support. So instead of inhibiting that response to a sensed event, we're actually going to use that to pace off of that sensed event. That fourth letter is going to be our rate modulation. And so that's whether or not we have rate response programmed on or off. So if a patient is programmed VVI, we're going to pace our ventricle, we're going to sense our ventricle, and then we're going to inhibit pacing. And that's it. If they're programmed VVIR, we're going to pace our ventricle, we're going to sense our ventricle, we're going to inhibit pacing if we see a sensed event. But we also have rate response programmed on, which is going to leave the patient an opportunity to increase their rate through pacing based off the patient's activity level that's sensed through the device. The last code, the fifth letter, is one that's very rarely used, and that's for multi-site pacing. And so I'm not going to get into that today because you really don't see that very often, and it's something that's probably more appropriate for an advanced discussion. Okay, so we're still on P. There's a lot to do with presenting rhythm, rate, and percent pacing. The last piece here is histograms. So what are histograms? Histograms are a graphical representation of each heartbeat since the last pacing session compared to a previous period of time. So what the device does is it says the device was interrogated by a programmer today. I'm going to clear out what I had seen before. I'm going to remember it, but I'm going to start a new counter to look at pacing and look at each heartbeat. This is really valuable as we're looking at response to programming changes or seeing how a patient reacted to a medication change, for example. So as we look at histograms, we're going to walk through a few examples of these, and I want you to keep in mind our four phases of pacing. So our ASYNC, VSYNC, ASYNC, VPACE, APACE-VSYNC, and APACE-VPACE. Some of our vendors, this example is Medtronic, will actually call those out for you so that you can see where your patients are spending the majority of their time. And I want to just orient you a little bit to how this information is presented. So we have prior to last session, and then we have since last session. There's also a time period there that says we had 91 days before the last session and 91 days since the last session. And then it's going to give us a percent of time that the patient spent total V-pacing and total A-pacing. This is incredibly helpful as we look at comparing periods of time. I want to always encourage you to look back. Don't ever just look at what's in front of you right now. Look to see what the patient was doing previously as well. And then also give us percent of time in those four phases of pacing. Now underneath the numbers, we have our graphical representations. So the first set of graphs there are atrial events and the second set are our ventricular events. It's really important to know that these are separated. They're not together. And it's also important to be able to interpret these graphs. You can see there that the A senses are clear bars, the A paces would be black bars, B senses clear, B paces black. And what we can tell from the counters is that this patient very rarely paces, very rarely. So 99.9% of the time they're in normal sinus rhythm and they don't need backup pacing support. The other thing to look at when we're looking at histograms are heart rate excursions. So we want to look at the histogram trend. We want to see if it's appropriate. We want to see a nice bell curve, which is exactly what this patient has. So we want to see some lower rates, some higher rates. We don't want to see anything where the rates are right shifted or the rates are left shifted, or you've got all of your heart rates in one bin. And we'll look at a few other examples of these. So let's look at this example. So first of all, let's think about what we can learn from this device. So right off the bat, we know that it's a dual chamber device because we have both A sense and B sense counters here. We also know that the patient B paces a large majority of the time, which could tell us that they have some sort of AV block. That would be the most reasonable explanation. We can also see that they need some level of atrial pacing support. So whenever we look at our counters, so again, and we want to look at our times here. So prior to last session was 90 days, since last session is going to be the last 91 days. So we're B pacing a lot of the time, 96.7% and 94.9%. We also have a fair amount of A pacing, so 15.4%. And then it actually went up a little bit since that last session to 21.9%. The percent of pacing for the four phases of pacing are also interesting and just important to note, but probably not spend a ton of time on. And then let's look at the graphical representation here. So what we can see is that we've had a little bit of a difference in our heart rate excursions between the two sessions. You can see that we've got more of a stair-step approach since the last session. It was perhaps a little bit flatter on the one prior to that. These are both fairly appropriate histograms though, and neither one of these raised big concerns for me. It is important to note that all of the heart rates are less than 100 beats per minute, so I would also anticipate this patient was probably a little bit older or not very, not as active because we're not getting our heart rates above 100 beats per minute. So again, these are things to keep in mind as you're looking at your patient and evaluating these heart rates. How does the patient feel? Are they able to achieve a heart rate they want to? Are they limited in their activity level? The other thing that I would do with this device is make sure that we check intrinsic conduction, and we're going to talk about that a little bit later today. But we want to make sure the patient actually needs to v-pace because we know that RV pacing can cause problems like cardiomyopathy, increased incidence of atrial fibrillation. And so if a patient doesn't have to ventricularly pace, we want to limit that as much as we can. Let's look at another example. So this is an Abbott device. Those last two are Medtronic devices, and Abbott gives you a little bit of a different view here and also a little bit different information. So what we can see is that our atrial heart rate histogram is at the top. Ventricular is at the bottom. Again, they're separated out. Abbott will also give you information about where the device thinks the patient's heart rate should have been based on the sensor. And you get this information whether or not the sensor is programmed on. So if you remember that fourth letter in our programming code is rate response. So what this is telling us is that if rate response was programmed on, the device says this is where their heart rate should have been. And that's notated by those clear circles on both the atrial and the ventricular histograms. We can also see that the A-sensed events are going to be the clear bars. A-paced are the blacked-in bars. B-sensed events are going to be clear. B-paced are going to be the blacked-in bars. And so again, what we can notice from this patient is one, it's a dual chamber device because we have both atrial and ventricular heart rate data. We can see that the patient ventricularly paces almost all of the time. So we could assume again that they have some level of AV block. We also don't see any pacing above that base rate, which would tell me that probably rate response is not programmed on in this device. And their histograms are appropriate. So that's what I would take away from this histogram. Let's look at another one. So this is another AVID device. Again, atrial histograms at the top, ventricular histograms at the bottom. You get those clear circles again for where the device says, okay, I think this is where the patient's heart rate should be based off of their activity level. And then we have a very interesting atrial heart rate histogram. So what we can see is almost all of the events here are greater than 300 beats per minute, and they're all atrial sensed events. So what do you think that means? For me, it would tell me that this patient is probably an atrial fibrillation almost all of the time. And then whenever we look at the ventricular histogram, I would call this histogram a little bit right-shifted because we have heart rates that really begin at 80 beats per minute. And we're seeing that our base rate and also our sensor indicated rate shows that they should probably be in that 60 beats per minute range. So for this patient, I would want to evaluate how they're feeling. This might be completely appropriate for them based off of their activity level and what they need from a sensor support standpoint. But I would want to make sure that we didn't need to do anything to lower their heart Here's another example. This is a Boston Scientific device. Interestingly here is that our reset before last was 280 days. Since last reset is only seven days. So this is a really good example of why it's important to pay attention to those time intervals. Because say, for example, a patient was in a hospital and they had a heart attack. They had a heart attack, they had a heart attack, for example, a patient was admitted to the hospital and then they come to see you a week later. But we only really have seven days of information. And so is that enough information to be able to justify programming changes or be able to interpret what's going on with that patient? For some patients that's yes, for other patients that's no. But just understanding what you're looking at is really important as we're looking at these intervals and what information is contained there. So for Boston, atrial events are blue here. So our pace events are the ones that are halfway like that kind of dotted line shaded in. Our sensed events are the fully shaded in bars, which is opposite of what the other two manufacturers that we looked at were doing. Also very important to look at your code up here and understand which represents pacing and which represents sensing. And then we have our RV and our LV. So what can we learn about this device? Well, we know it's a CRT device because we have atrial, RV, and LV events. We also can see that the patient rarely apaces, a little bit of apacing, but not much. Their sinus node is really pretty healthy here. We also notice that they're bi-V pacing almost all of the time. And both of these histograms, the 280 days and the seven days, are really appropriate for a CRT patient. And I wouldn't anticipate making any changes based off of this information alone. Okay, one more example. So what can we learn about this device? So let's start from the top here. So V sense is less than 0.1 percent, V pacing 100 percent of the time. And then we have a histogram that only has ventricular data. So what we can learn is that either this patient has a single chamber device, or that the patient has an atrial lead that's not programmed on, and their device is programmed VVIR, VVI, something. But they're programmed to only ventricularly sense and only to ventricularly pace. So even if they had an atrial lead, we know that lead's programmed off right now on this device. So our V sense events would be clear, our V pace events are all shaded. So what we can see is graphically represented by the numbers there, that 100 percent of the time we're V pacing, we're also 100 percent of the time V pacing at 70 beats per minute. And so I would hazard to guess that this device does not have rate response programmed on, but that would be the first question I ask myself about this histogram, is should we program rate response on? If you think about your heart rate, if you get up and walk to the bathroom, or if you get startled, or if you have to jump up and go grab your kid, your heart rate's going to increase. Our patients also need that heart rate support. And so a histogram like this where all of their heart rates 100 percent of the time are one rate, my guess is the patient doesn't feel as well as they could if we gave them a little bit of rate support. So for this patient, I would probably look to be seeing if I could program rate response on, do a whole walk while they're in the office, let them climb a flight of steps if you have it, come back, re-interrogate the device, see what the device did, see how the patient feels, and see if that's the appropriate thing to do for that patient. So that concludes our presenting rhythm, rate, and percent pacing, and that was a lot of information. So we are going to take a break here and then pick up with our battery status in part two.

interrogation basics

device patients

follow-up evaluations

arrhythmias

intracardiac electrograms

structured device follow-up

pacing modes