[1] It is a pleasure to be with you and be behind the now virus laden... microphone courtesy of Dr. Bernstein. Thank you so much. I am a practicing electrophysiologist in the Cleveland Clinic Health System and did a fair number of implants but my charge this morning is to talk a little of a brady and tachy parameters the way we program them and we might talk a little less technical and a little more focus on the concepts behind why we program things the way we do. [2] As always, we have to do disclosures. I actually have two. I have served as a consultant and speaker for Guidant, which of course is now Boston Scientific. My second disclosure has to do with the sport of basketball, which I have enjoyed playing competitively for over 30 years and in spite of playing for that long, I do not have half the talent of this young fellow from Northeast Ohio who earns considerably more with each dunk of the basketball that I will ever earn on honoraria from Boston Scientific. So, hopefully many of you watched the game last night as the Cavs took down the Pistons. [3] Alright, I thought a good place to start was to go through what the nominal program settings are on a variety of tachyarrhythmic devices. For the sake not being proprietary, I will call it ICD product A, B, and C, but this is basically what the unit would look like as you pull it off the shelf or your paced her up, pull them out of your trunk that has more street value than what is carried by the average drug dealer, and you pull a device out of your stash and if you would just put it in and turn it on after you have implanted it, what would the parameters look like? Of course, there are brady parameters set for our typical dual chamber defibrillators and the vast majority of our devices are dual chamber. We do have very small percentage, I would say under 10% of single chamber defibs. Of course, you have got your standard pacing parameters here and your AV delays and mode-switching may be on or off depending on the manufacture. [4] There are also of course the tachy settings which come out of the box. Basically, all of them come out as single tachy zone devices without any finesse stuff with VT or anti-tachy pacing or so forth and are set basically to high energy shocks. [5] One of the focus first on the brady side of things and kind of conceptually one of the thoughts over the years from the same area of Dr. Bernstein, we grew up in the area where people would sometimes have pacemaker and a separate defibrillator. We thought why that is going to be wonderful. We combined the technologies and we can offer pacing toward defibrillator patients. Many of them do not have a classic pacing indication. Obviously if they did, they probably already have a device, but some of them have some low-grade sick sinus syndrome or some AV conduction problems. So it makes sense that it would be nice to offer dual chamber pacing for people that get devices. The big thing and it was touchstone in the earlier talks is this issue, chronotropic competence. Many of the patients that we put defibrillators in are on beta blockers, pretty big doses, are on amiodarone, and a variety of drugs that can really limit your ability to increase your heart rate with exercise and if you are stuck at a heart rate of 60 beats a minute, that is fine when you are sitting watching TV, but when you are trying to run and catch the bus, you are not going to do very well. So chronotropic competence is a big deal and I would like for my patient to be able at least get a heart rate of a hundred. When they do things and that is adjusted by age and we have various algorithms to kind of sort through that. Cardiac output of course is the product of your stroke volume and your heart rate and many of this people that get defibrillators have limited stroke volume because they have poor ventricular function. This will make sense that by increasing the heart rate even if it is modest, you know from 50 to 70 beats per minute, you may do a significant good job increasing the patient’s cardiac output and perhaps their state of well being, tissue perfusion, renal function, and so forth. Finally, one of the manufacturers has an algorithm where your PC atrium is faster than the sinus is going, a new hope to suppress atrial fibrillation. It is not an overwhelming data but there are some data that suggested that may be beneficial for truly helping prevent fibrillation in patients. However, there are concerns about setting pacing up in patients who are getting defibrillators when they do not have a pacing indication. Here is one of them, increasing the myocardial oxygen demand is not a great thing to do for someone who has got, say, severe multi-vessel coronary disease and I am sure many in this room have seen cases where people who are angina free with bad coronary disease and you put a device in them, be it a pacer or a defib and you start pacing them fast or low, and behold, they start getting a lot of angina because of the increased myocardial oxygen demand that comes with the faster heart rate. The more you pace, the shorter the generator is going to last, although that is relatively a minor issue. If you pace that all the time and we certainly do not want to do this when someone says he has got a sinus tachy at 110, 120, and a heart block, you do not really want to track that and pace them at a 110 or 120 beats all the time or you may develop some degree of a tachycardia-induced cardiomyopathy. So that is a theoretical concern and then this is a concern that it is kind of interesting, deleterious hemodynamics of right ventricular pacing. We have known for decades that the stroke volume on a paced beat is not as good as that on a beat that is due to conduction through the normal purkinje system, but it is a modest difference and we have always felt like in the past, that is a small price to pay in order to attain some of these other goals like chronotropic competence. So, when the dual chamber defibs came out, we jumped on the bandwagon, and we are putting these in everybody and ended up pacing the right ventricle quite a bit of a time thinking we were doing people a favor. It is interesting, the turnabout just happened in the last few years. [6] That is largely due to this particular trial called “The Dual Chamber and VVI Implantable Defibrillator Trial”, the so called David trial which was spearheaded by my good friend and colleague Dr. Bruce Wilkoff at the Cleveland Clinic. This is a trial done few years back that was looking at the ideal pacing mode in someone who has got a defibrillator and his hypothesis was really that with dual chamber pacing, you would improve the prognosis of people treated with defibrillators and improve their quality of life, but it makes sense that chronotropic competence is a big deal. It might also reduce the cost, but this is the main hypothesis [7] and so what Dr. Wilkoff and his colleagues did was they took eight hundred patients with ejection fractions under 40% and standard defibrillator indications. They did not have pacing indications so this was not people that needed the pacing itself but they were getting a defib for VT or primary prevention or whatever. All of these people were on optimum medical therapy and were randomized into two groups. The first group was set up for DDDR pacing, low rate is 70 with typical AV delays and mode-switching was turned on to one hundred eighty beats per minute. So this was the pretty standard way we would typically set up a dual chamber device on a patient. The other group was set up just for plain old backup VVI pacing at 40 beats per minutes and obviously not going to reap much benefit of pacing at that rate. At the end of one year, the percentage of paced beats in this group was only under 3%. So this people really do not pace except in the middle of night when they are sleeping. This group though DDDR mode, the ventricular paced percentage was pretty sizable over 60% of their complexes were V paced and so how did they do? [8] Well, very interesting trial because the results were not intuitive. What they found was that at the end of one year and this is looking at the combined endpoint of death or hospitalization for heart failure, the one year event rate in the people that have just plain old backup VVI pacing was 16% whereas those who had the DDDR pacing, almost 27%. Huge difference! That reach the p value of 0.03 and so lo and behold! This was not at all expected and word got out, boy, DDDR pacing is not a good thing for people that have dual chamber defibrillators if they do not need backup pacing. [9] So, the conclusions drawn from this trial are basically that narrow QRS complex and native rhythm even if a little slow shown in the sinus bradycardia in the 50s, that is a winner compared to dual chamber pacing with a wide QRS complex which is a big loser. They found the DDDR pacing increased the combined endpoints of the death and congestive heart failure hospitalization in comparison to the backup VVI pacing group and there were no benefit and in fact, significant detriment associated with DDDR pacing in these patients. [10] So the implications of this particular trial were that since DDDR pacing increases your heart rate, alters the AV interval, and alters ventricular activation, which is probably the biggy here, altering the ventricular activation, and the percentage of right ventricular pacing clearly correlates with poor outcomes and that has been shown in other studies. If you pace more than 40% in the RV, you are in trouble and the less you pace, the better, but since these things were shown in the study, we felt that ventricular dyssynchrony caused by right ventricular pacing, much like what we see in our heart failure people with left bundle, the ventricular dyssynchrony produces this outcome and should be avoided in ICD recipients who do not have indications otherwise for pacing. So the DAVID II trials, finishing enrollment and that is looking at AAI versus DDD, but the take home message from this trial is, “Do not pace the right ventricle unless you really have to because it is not a good thing, it makes people worse rather than better.” [11] So as we look at the way our three main companies here come out of the box, you see where 150, 180 milliseconds, is that long enough for all? For a lot of people, it is not. You just put them in nominal settings. You are going to pay CRV a whole lot more than you want to and you will probably fuse even in people that have relatively normal AV delays. [12] So what are the strategies that we can use to minimize right ventricular pacing, if it is really such a bad thing? One thing you can do, of course, is just to program along AV delay and different manufactures brought you different levels, some 300 to 350. At some point, it is not very physiologic if you are pacing at an AV delay of 350, but programming long allows you to have intrinsic conduction. It does hamper your ability on other things in terms of... and your upper rate and so forth, so I do not always like to program, I am on my way out there. Another option that was conceived anyway is this, how about if we just pace AAI or AAIR? Well, as attractive as that sounds, boy you got a lead in the ventricle and what if the patient really did have heart block? You would hate to not take advantage of having that lead there and I think Dr. Olschanski’s group just presented a case report where someone with a dual chamber defibrillator that had been programmed in this way and came in with multiple syncopal episodes due to heart block, and so this is not recommended. Do not do this at home. So we comment that and I have to tip my hat to the very bright and very sharp people that work in the industry because they are helping us get around this problem with a variety of different approaches. One of them has already been touched on and you saw this on Amy’s presentation. This is what some referred to as the ADI mode where you pacing the atrium, you are sensing in both chambers and the idea is it effectively works like AAI pacing as you are going along, so you get a pace, normal capture, intrinsic AV conduction and narrow QRS complex. We are okay with this. This is not RV pacing, this is good. However, when you get a p-wave that fails to conduct, what happens? Well, in this situation, the algorithm is set up so that you actually be paced on the next atrial event, takes another look to see if AV conduction has come back. If it has not, then it converts over just like we are used to mode-switching from DDDR to DDIR for someone who goes in afib. This is a mode-switch algorithm that basically goes over to DDD or DDDR pacing. Another approach is this, what you called AV search hysteresis and this goes by different names with different companies but it is the same basic idea and if you follow through this rhythm strip at the bottom, I will cover it briefly with you. This is a situation where someone is set up with an AV delay of 150 milliseconds, not ideal as we have got RV pacing here obviously. However, every so many cardiac cycles in this case is programmed every 30-second cycle, it will artificially stretch out that AV delay by a programmable factor, in this case 50%. So, you suddenly go from 150 up to 225 milliseconds and do it for x-number of cardiac cycles and as you do that, long behold the sinus or the native conduction comes in here, and so this is preferable to this, and so the unit will affectively mode-switch to a longer AV delay for whatever period of time. So now it has basically changed this AV delay from 150 up to 225 where it stays allowing intrinsic conduction until you get to the point where intrinsic conduction fails, then you begin to pace again, then it shortens back down, then it recursively repeats the cycle but the idea again is the same, to promote native conduction as much as we possibly can. Again, I tip my hat to the industry, which is helping us solve these problems. [13] Let us turn our attention to the tachy zone features. This is, like I said, if you take them off the shelf, none of the fancy stuff is programmed. So each company basically just has a rate cut off and is set up like the old fashion shock box. [14] If you think about shock box program, we use that term affectionately of course. Shock box is basically thought of just you got a, you may have a backup brady zone say under 40, you are going to backup pace but it is basically a normal zone you have, and a tachycardia zone, so it is some magic number that you pick out of the air, some magic number above that, is bad and below that is good, and if you’re in this so-called normal range, well, you do nothing but yawn and no matter how presidential your company, whereas, if you are above the magic cutoff, you just give them right to the jaw and put them on the canvass and take them down and it will hit them with a big big shock. So this is kind of the old original defibrillators. This is kind of how they work even without the backup brady. So some magic number, you zap them, anything below that, you just yawn about it. [15] So, what are the problems with this kind of programming and some of the previous speakers touched on a few of these things. One of them is certainly up in this tachy zone. You may end up with inappropriate shocks. It is a good way to make a patient miserable and especially for sinus tach or for afib, they can get repeated shocks that are ineffective and they will go through when you are a few things more miserable than a patient who has had twenty shocks and comes to see you. So that is the potential issue here. Even more serious issue is this situation where at the high end of what you consider the normal range, people are having stuff that could be dangerous to them. I had a gentleman with an EF of 10% who put a bi-V defibrillator in and set it basically kind of shock box style, and he ended up having a syncope and arrest for a VT that was well below the rate cutoff that we had put in. He never had VT in the past, but I mean it happens and so you may be missing things here. [16] So one thing you can do that is very easy is to at least open your eyes to the device and give yourself a monitoring zone. With some of the companies, you have to finagle a little bit because it takes an extra zone but it can be done with all of them. With this idea, you have a rate cutoff where above that you are going to zap them but you will have at least a zone where you may not deliver any therapy, but at least you are open in the eyes of the device to pick up any nonsustained VT that may be occurring in this area see or if they are having sinus tach up. It is important to know about it. If my guy can get to 160 when he is on his treadmill at home, I certainly do not want to program him to potentially receive shocks for that. I do not really see any downside of programming in a monitoring zone. I think it should be done for everybody. [17] Now, what about antitachy pacing? Well, Dr. Bernstein’s young lady did not do very well with antitachy pacing but it can be effective. This is a real life tracing from a few weeks ago of a patient of mine that came into the hospital and he was doing this literally dozens of times a day, would be sitting around have a PVC tube going to sustain VT in his defibrillator paced him out and it sure beats getting a hundred shocks. [18] So, mechanistically we have know for years that slow reentrant VT by penetrating the tachycardia circuit that you are able to effectively terminate VT in high percentage of cases. [19] The faster the VT is, you have the smaller of what we call an excitable gap here and it is a little tougher to penetrate the circuit and terminate it, but even in a trail called the pain free trial and followed up with the pain free II trial, they show that efficacy is not bad, 75%, 80%, you can still do it even on the rapid VTs. [20] So perhaps a more, I am sorry let me touch on the benefits and the concerns about ATP before we go into kind of the final programming. Obviously, the main benefit of anti-tachycardia pacing for a patient with a defibrillator for arrhythmia termination is that it is painless and nobody likes shocks than anything, even two joules or above, you get the startle factor, you get the pain factor, they are not happy and if you can pace them out as opposed to shocking them, that is much preferable. You may have a briefer time to therapy because you do not have to charge up the capacitors, you know which takes a certain period of time. The patient may be totally unaware of this and you may improve the generator longevity by not delivering multiple shocks. However, there are these concerns that come up and Dr. Bernstein highlighted one of them. One of our concerns here is, there may be an added time delay to the delivery of the shock that is really needed. Someone goes in the VT of 190 that may be hemodynamically compromising. You do not want to sit there and pace him for two or three minutes trying to pace him out before you deliver a shock because they may have syncope and crash your car by that time. So it may increase that time delay which is not a good thing. You may accelerate them to a faster VT or VF as they do in New York City. If the patient is unaware, like I said, that may be a benefit but that may also be a concern, a guy is having a lot more VT and does not even know it and may need change in pharmacologic therapy. My particular patient who was getting all those ATPs, I put him on a higher dose of amiodarone. Certainly, there is a greater level of sophistication needed by the programming physician and the staff on how you set these things up, do you do burst, do you do ramp, decremented, how many beats, or what percentage of VT, I mean there is a lot of stuff to program but it can be done. One of the ways the industry is trying to beat this problem is one of the companies has ATP during charging which thereby does not steal away time while the device is getting ready to deliver a shock if needed so that is a nice feature that I am sure all the companies will eventually have. [21] So a more sophisticated way of programming a device would be this. You have of course your brady zone and your normal zone, but you may have three tachy zones set-up where you, say a rate above 200 for example and you give him the high energy shocks. I am not aversed to setting the first shock, it just 10 over the safety margins if you get successive 10 joules in the laboratory. It will sure make sense if you do a 20-joule shock and then go to max because you save a second or two on the charge time. A faster VT zone in this instance 170 to 200 you may set-up ATP, give that a few tries and then go to lower energy shocks before you ramp up to the big stuff and in the low end, you may try ATP or you may just have a monitoring zone but you may not have any shock therapies on here, if they are not going that fast it is not worth zapping him, you would rather they would show up in the sustained VT with their normal blood pressure and you deal with it, give them a little propofol and then shock them. Certainly, for VT1 and VT2 zones here there is a lot of stuff we can do with discrimination between sinus tachy, fib, and some of the things that have already been touched on. [22] So, in summary this quote came to mind, “With great power comes great responsibility.” I am sure many of you recognize that it is coming from Uncle Ben Parker as he spoke to young Peter in the Spider Man movie, but if you think about it, among not too many people in the world that can put their finger on a button and deliver a T-wave shock to put someone in the VF. I mean it is a pretty awesome responsibility in playing God in a strange sort of way. [23] So, my take home message is on the brady and tachy pacing are these. First of all, avoid right ventricular pacing if at all possible and again we are coming up with these algorithms to try to minimize that. If you absolutely can not avoid it people have PR of 400 msec and you are stuck, well then I would go right to buy ventricular devices because you know you are going to pace all the time. Second take home message, even for a prophylactic defibrillator that you are putting in for primary prevention, do not just set it up as a shock box, and always put in at least a VT monitoring zone so that you can enhance the ability of the device to tell you what is going on below that magic rate cut-off. Thirdly, consider inferior anti-tachy pacings sometimes you get burned as in the case we saw before but other times it may really save people out of shock and they will be grateful. And then finally, remember that we do treat patients and not devices and you have to individualize these things for the particular needs of the patient. [24] So, anyway, my final disclosure is those of you here from Detroit, Michigan which is by the way where I did my fellowship and that is, in case you missed it last night the Cavs did beat the Pistons but two points and hold a 3-2 lead in the series. [25] [25]

Robert Mosteller 157ABC Programming for Brady and Tachy Customization for Optimal ICD Programming: Troubleshooting and Case Presentations