Cardiac Devices

Rinat Malik: 00:00:00

Hi, everyone. Welcome to another episode of Tech Talk. Today, we're going to cover a area of topic that we haven't covered a lot. It's going to be med tech. We're going to talk about a topic in med tech medical technology. And you'll notice we have a guest with us today. I'm very pleased to introduce Abhijit Mandel. He is a researcher at Boston Children's Hospital. And working with various medical technologies, especially cardiac devices. I'm actually quite interested to know more about your interdisciplinary knowledge because we were just talking earlier and I found out you were also a mechanical engineer, like both of us, start of your career or at the end of your education rather. So it's really interesting to sort of find out how we all change paths in our career and how we ended up here and how we basically input our educational knowledge into our current career. I feel it's gonna be an interesting insight into that world. So I'm really pleased that you agreed to join us Abhijit with us today and looking forward to our talk. So let's, let's start by a little bit of introduction. So if you give us a little bit,

Abhijit Mondal: 00:01:22

Yeah. Hi. So welcome to everyone, I'm Abhijit Mondal. I am a research fellow here at Boston Children's Hospital. As Rinat mentioned, my Bachelor's was in Mechanical Engineering. My master's was also in mechanical engineering. And then I did my PhD in Biomedical Engineering, with focus on cardiac electrophysiology and sort of cardiac diseases basically. After that, I moved to Boston here in Massachusetts and I am working with a cardiac surgeon. We work with working on certain devices associated with basically cardiac and respiratory diseases or treat treatment of that. So one of the aspects of work here is, is to do with cardiac imaging. We do a lot of intra operative imaging for identifying and looking at tissues and things like that. I'm also working on some other technologies basically on airway stents, which is again, goes to trachea little away from the heart but still in the respiratory system or the thorax, which is where your chest where your lungs and your heart is. So I'm doing like multiple projects like that. Yeah, so we study the heart, which is like the main focus of the work that we do and things that are around the heart.

Rinat Malik: 00:02:57

Wow! Thank you for that introduction. Amit, you guys know each other from beforehand, right?

Amit Sarkar

Yes, actually. So thanks Abhijit for joining and thanks Rinat for that lovely introduction. I actually know Abhijit, from college from our university days, so we studied together we both studied Mechanical. We were in different classes. But we studied. We did the university education for four years together in southern part of India. So yeah, we have been roommates after college graduation, for a couple of years before Abhijit decided to move to us for his highest studies. So thanks again Abhijit for coming on the show. And thanks again for that introduction about your career. So that's actually quite a pivot that you have taken from starting from mechanical engineering and moving into this medical field, per say without a lot of medical knowledge, but he still managed to apply your mechanical engineering education into this field. So it's actually quite fascinating to listen to you. Just talk about that bit right now. So I think for the benefit of our audience, let's start first with like, why cardiac devices? Was it by chance or was it like an opportunity that came or what why did you decide to select this area of research?

Abhijit Mondal: 00:04:26

So yeah, I think part of it was by chance, I guess by the opportunity it presented but I think during my undergraduate education itself, I was very interested in interdisciplinary fields. So if you recall, when I was an undergrad, I was obsessed with robotics and the aspect that I loved about it was it involved using mechanical aspect of it, there's electronic aspect of it, and there is a huge computational aspect of it. And my initial training when I came here for my master's, I tried to do a master's in robotics that I ended up in a project which involves some amount of robotic instrumentation, but it was for doing something more bio mechanical, I would say. So I was trying to micro fabricate this device which could roll up automatically by sensing without like, crushing some tissue which was sort of a long shot project, which ended up not being that way. But I got involved in more biomedical stuff in terms of generating cardiac tissues while I was in my grad school, and from masters that sort of spurred me into biomedical engineering. The center where I was working was the was basically for cardiac research, the CVRTI which was cardiovascular training and research institute at the University of Utah there and then when I was working, the work that was very bench oriented. So, I was working with cell cultures and things that you do only in the lab. And so I got a little bit more exposure to like doctors, some of the professors that were actually practicing medicine they were cardiologist, so my interest was more towards going the clinical side and, you know, doing something that's more contributing or directly helping patients, you know, so, and the term use in the field is called bench to bedside. So you know, you're trying to come up with the science and techniques on the bench. And then bedside means something that you made actually ends up to the patient or in the clinic. So that was sort of what motivated me towards making that shift. And I could see that a lot of the techniques and my engineering training I can use in this biomedical field in understanding what the diseases are diagnosing what the diseases and you know, in best case scenario, treating the disease I mean, that would be like you know, it's like the goal as a scientist, whatever you make ends up helping someone.

Rinat Malik: 00:07:01

Absolutely, And one of the things I remember I was talking to a PhD student in Cambridge University about four or five years ago, and this what you said kind of reminded me of that conversation and he was basically saying that in next five to 10 years, anyone with interdisciplinary knowledge would become really successful and, and this was five years ago, and you know, I see that in my career and everywhere where I look interdisciplinary knowledge is where new innovation comes all the time because as soon as you have two different expertise, you have so many new opportunities, innovative ways to combine those knowledges to create something new. It's incredible. How many new ideas can come through with and the more you know, the more different it is in my opinion, the more chance of innovation there is or disrupting the market there is because in each of these industry, people are working in certain ways and if you come from a different industry knowledge, you can sort of apply the good sides of each of these and I feel like that you have a unique advantage on that having the two background so you know some of the medical terms you use I know all of them because I was raised in to me .All of them. I feel like yeah, my knowledge of just the words are quite well, but obviously when it comes to the actual application, probably just no! Go anywhere else. So from that perspective, in terms of cardiac devices, how does cardiac devices differ from other kinds of devices? What do you have to kind of specifically look at when you're dealing with that?

Abhijit Mondal: 00:08:56

So, so it depends what, what the device is being used for. So there are different levels of devices here. One is just monitoring things. So I mean, you can think of, so I think it will be better if I approach it from the different levels and functions of the heart itself. So you know, I mean, the hearts basic function is that it's it serves as the circulatory pump of the body. It enables supplying, basically oxygenated, it gathers the oxygenated blood from the lungs where the blood is oxygenated, and then it takes it and then pumps it to the rest of the rest of the body, and all organs everything it supplies, not just your oxygenated blood, but also the nutrients to all the body and that is what keeps the rest of the bodies of the organs of the body functional. So that is the primary role it serves. And based on that where you are looking at what this function, you have the devices created with that function. So you know, the, I guess the most basic the first thing that comes to my mind is the SPO2 to the oxygen saturation measurement. It's basically a direct measure of whether your heart is doing its job of pumping oxygenated blood all the way from the heart, from the lungs, to the heart into your finger where you sort of set tsp or 2 and if there are any dysfunctions in the heart, your SPO2 will directly go down so if it's unable to, if there is mixing of the oxygenated and deoxygenated blood in the heart, your SPO2 will directly go down, which is basically an indication there is something there's probably a hole in the heart and you know, things are getting mixed up. So that's probably the first level of just diagnosis. In fact, I think Amit will know he last year , like when the baby is born, this is like one of the first things they check if, if the heart is functioning properly or not.

Amit Sarkar: 00:10:59

Yeah, actually, so they put the same machine that we used specially during COVID. It has now become very popular that everyone wants to measure their blood oxygen level. So even with kids but kids instead of using it on their hands, they normally wear it on their legs, because it's just easier to put it on them and they constantly measure it at the time of birth and every couple of hours just to monitor and if everything is fine, they don't need to measure it. And the other thing is whenever you go into emergency because there's a I mean, as a as an infant, you tend to get sick quite often because you've just come into a whole new world with so many different biological organisms and you are bound to catch some kind of a disease. So whenever you go to emergency, the first thing that they do is they measure the temperature and then check the oxygen level of the baby. Because if those aren't stable, then they can check if it's an actual emergency or not. Otherwise they carry on with their normal diagnosis.

Abhijit Mondal: 00:12:06

Yeah. So that would be the first thing. But in terms of vital signs, when you think about it, the two things that come to mind is one is the blood pressure and then the other is the heart rate, which is again it's again yeah, the SPO2 itself. The pulse oximeter also generates detects your heart rate. It uses a different technology or similar technology. But yeah, but that's the one they use for just getting the oxygen and the pulse. The blood pressure is like the other device. I think you all have seen that blood pressure monitor the actual term is I don't know if you've heard of it. If you can pronounce it, it's calls “sphygmomanometer”. it's very hard to pronounce it it took me like I remember the first lab I did when I was in grad school. And it took me as just a big pain just trying to remember that name. And where they measure your systolic and diastolic pressure, which is like again, the fundamentals every time you go to the doctor. This is the first thing they check. And again, it's again a function of how well the heart is functioning or so that's the one thing then you have the pulse heartrate monitor which is again the SPO2. The ones that you were in the Fitbit uses slightly. I guess the underlying technology is the same but you know the light type is different. The SPO2 uses like red light and the IR that's why you see those red flickering light. The ones on your Fitbit or your fitness trackers I have a Fitbit uses the green light, which absorbs which is basically absorbed by the oxygenated blood and it measures as your heart pumps the blood, the amount of blood going through your artery and vein is also changing and based on that the absorption changes the amount it absorbs. And that is what they measure and then that is how they detect, you know what the heart rate is.

Rinat Malik: 00:14:07

Right. This actually reminds me of an interesting TED talk I've seen as well, where someone was trying to detect the heart rate from a video after person. So based on the heartbeat, our colour of the skin is very slightly changing which is not which is invisible to the naked eye but if you analyze the video the redness of the skin is also changing because of the way the heart is pumping the blood. It was quite interesting how, you know by that kind of analysis of that video, you could also get the heart rate. I think that's like one of them. One of the most sort of visible thing of visible feature, right. You know, people blush if they're nervous or shy and things like that. So Heart is actually quite you know sort of know how do I put this? So the know the state of the heart is actually quite easy for us to do and even socially we try to understand it very quickly. You know whether a person is nervous, anxious or whatever excited.

Amit Sarkar: 00:15:21

So I think I used to do a lot of cycling in Chennai and we used to monitor our heartrate very regularly and thoroughly. Especially because there are these different zones where if you exercise at those heart rate zones, then you will consume the maximum amount of fat or you will have the maximum amount of oxygen in your blood depending upon the heart rate and that's when you will be able to push yourself much harder, etc etc. So I think it's quite fascinating to see this heart and lung combination we used to call it the engine. So our body has this engine which is the lungs and the it's like the carburetor I think and the and the engine where we are getting the fresh oxygen and we supply to the blood and then the heart pumps the blood to the rest of the body. And it's just incredible.

Rinat Malik: 00:16:18

So we've talked about the monitoring part of cardiac devices, but I'm sure they're I mean, if we want to divide, you know, like categorise based on the type of work they do. So if you want a few of them do monitoring, but then what other kind of aspects of cardiac devices are there some of them I would imagine would be helped to in the operation theatre.

Abhijit Mondal: 00:16:47

Yeah, so that is going I guess, to the other extreme of it, so I think so. I think one of the thing that as Amit was telling me that his discussion topic basically, the thought that comes to my mind was like the, the cardiopulmonary bypass system that's there, which is what you need during surgery. But, so, I mean, yeah, so for any cardiac surgery, I guess the main machine everybody comes to mind is the heart lung machine, what is called and it is used to bypass the function of the heart temporarily, so they can work on the heart itself. And, and I think that's, yeah, so it's, it's basically a pump system and the way so if you're going to the “OR” the surgery, the surgical aspect of it is the surgeon wanting to do any kind of repair on the heart. It's difficult when the heart is beating, and you can't and the heart being such a vital part of your life, you can't stop the heart. If you stop the heart, blood stops pumping, reaching the organ to die basically, it's sort of one of those futile, futile organs. And the way they do the bypassing thing is to use a separate pump, a pumping system, which sort of bypasses the heart. So the pumping is done through this cardiopulmonary bypass system. Basically, during the while your heart is on this bypass system, not your heart your body is in the bypass system. They use this solution called the cardioplegia which is sort of a concoction of a solution with some ions particular ions, which basically stopped reduced basically stopped the heart from beating and if you see the way the heart beats, and it's basically made up of these muscles and excitable cells, and what, what the solution does is it goes and changes the electronic environment of these cells in the cells, which stops this heart from creating the excitation so your heart actually literally during once they send it on cardiopulmonary bypass, the heart stops beating. But mind you, the heart, I think the incredible thing about the heart is it is not just supplying blood to the rest of the organs, but also itself. So the sort of bypass when the heart goes and bypass, it's, it's supplying, you know, it's supplying blood to the heart itself. At the same time, it's supplying things to supplying blood and nutrients to the rest of the body. It's as well. So yeah, for cardiac open heart surgery, any kind of surgery that they do on the heart requires I think the main star of the show is this cardiopulmonary system. And if you go to a cardiac OR it's a huge team effort it's not I mean, there is the primary cardiothoracic surgeon who's going to actually who's trained and actually is going to operate on the heart. But then there is the anus, the anesthesia team, which maintains that the patient's vital systems are fine and the patient remains in the in that sleep is that the what we call the put putting the patient down. So it's remains in under anesthesia. And then then you have the pump team, which controls and sees that the pump pressure is maintained at the correct pressure is you're not overloading the heart or the body. And then of course, there's the CIRCULATING NURSE and all who are looking at it, who are just, you know, managing everything that's going on in the OR, keeping tabs of all the personnel. Then we have a. Each surgeon has a PA. Physician's Assistant. So this is the person who is actually standing right next to the surgeon and handing off the equipment as the surgeon needs. There's a whole range of equipment he needs for the surgery, he or she needs for the surgery. So, so there's a lot of things there's a huge team effort going on there is you know during a cardiac surgeries that I have been, there are at least 10 to 15 people involved during these surgeries. So yeah, it's a there's a lot happening there. I would say. Boston Children's Hospital is actually a training hospital. This is where surgeons get training. So sometimes there is an additional third person who is the trainee who's standing on the other side of the OR bed being trained by the by the surgeons who's giving him instructions.

Amit Sarkar: 00:21:25

Wow, that's quite interesting Abhijit. And I mean, when you were talking about it, I think yeah, you covered that point that heart has to supply blood to itself. But you've seen movies that they try to give an electric shock to the heart. So what is that part? And why does a heart need electric shocks to get revived?

Abhijit Mondal: 00:21:46

Yeah, so I think so for that I think I have to move a little bit step back a bit and talk about the functioning of the heart, you know, so I think most of us think of heart as a pumping. I mean, it's basically a pump, biomechanical pump. The way I like to think about it, it's you know, it's a bio electromechanical organ. So it's got an electrical component of it as well as a mechanical component of it. The mechanical component being the pump, right? It's got these chambers, it's got these valves between the chambers. There are this piping structure, which is the, you know, which are the great vessels and all so it's bringing blood in, getting it into the right atrium. There's a valve that controls it. From there, it goes to the ventricle, the ventricles basically, I mean, the ventricle then sends it to the pumps, it backs to the lungs where it gets oxygenated, comes back through the arteries, and then the pulmonary, sorry, pulmonary veins, comes to the left ventricle, left artery, sorry, left atrium, then to the left ventricle and then from there, it gets pumped to the rest of the body. So that is the mechanical aspect of it. There are four chambers, the left side, sorry the right side, gets deoxygenated blood. The left side pushes oxygenated blood deals with oxygenated blood. And as you know, the atrium contract the so the pumping occurs, the contractions occurred stop and then bottom of the heart even though it's divided left to right. So the atria first pump blood pumps in and then the ventricles contract, push blood out. And this synchrony of and the rhythm of both these chambers, the levels of chambers is maintained by the by the electrical or the bio electrical system of the heart, which is which we call as the cardiac conduction system. And so what happens is so your heart is made up of these excitable cells, and there are two types of excitable cells, ones that are intra ones that need an excitation voltage. So like you need to give it a shock for it to start beating. And then there are these pacemaker cells or what is what we call as a conduction tissue cells, which pays on its own. So and our heart has two of these basic units. One is that the sinus node, which is right on top of the Atrium, it's sort of somewhere near the one of the vena cables, it's on the, on the right atrium, and then there's one that sits it's the atrioventricular node, which sits between at the junction of the atrium and the and the ventricles, just over the septum. But the wall is and so this SA node is basically what shooting basically these electrical signals, which get transmitted across this conduction tissue, which sort of, you can think of it as a wiring that goes and excites your ventricles and atria which when a when it gets excited, when you when you pass that voltage it contracts and then then it repolarize and it just sort of expands. So it is this electronic this conduction tissue or a bio electronic aspect of it, which sort of you know, maintains this rhythm and creates these, these beats and the contractions.

Rinat Malik: 00:25:12

So the defibrillator actually puts the heart back into the rhythm or does it actually starts the heart when it's sort of not beating? Because yeah, in movies, you see, you see a spot beating and you kind of shock it back to life, but I also read somewhere that it's not about beating or not beating, it's about it kind of loses the rhythm and the kind of reset it.

Abhijit Mondal: 00:25:37

Exactly.

Rinat Malik: 00:25:38

Right. Okay.

Abhijit Mondal: 00:25:39

Exactly, So you have to just differentiate there are two types of these devices. One is the pacemaker. So when some of these hearts use this pacing have some sort of dysfunction on these pacemaker cells. And they need these. They're called permanent pacemakers, which basically supply the beats is the beat that the sinus node or the AV node is not able to supply and that's what causes the beating. The defibrillators which are called ICDs, which is intra implanted cardioverter defibrillator is the thing it's the term and they are exactly right. So when this electrical sometimes when you have arrhythmias these are like conduction issues, it's still a hot topic of a surgeon trying to identify and study how these are caused and all. Basically this conduction. Basically this conduction, this rhythm is somewhat disrupted. And what happens is you start getting sudden spikes up like I think these are collector pic beats, they're like regions, this random beats, this rhythm gets disturbed and you're exactly right the defibrillator basically shocks the heart, when it detects such irregularities and it just resets the conduction back. So these patients basically Yeah, so the defibrillator what it does is basically it has a sensor, which senses if there is any, you know, different relation any sort of arrhythmia or irregular beating occurring, and when it sees that within a particular time period, it is not able to resolve this fibrillation or, or arrhythmia. It sense it starts begins to shock the heart artificially.

Rinat Malik: 00:27:24

Right, Okay. So we don't see the monitoring part at all we just see the doctor just say 123 clear and then shock.

Abhijit Mondal: 00:27:32

Well,So Yeah, So when the heart is stirred, yes, exactly. You so that is so that is the defibrillator you see outside. You know, So I think one of the very big and very big industry for medical devices is are these implantable cardiac ICD devices.

Rinat Malik: 00:27:53

Yeah,you were mentioning the word pacemaker as well. And I was gonna ask that we know a pacemaker is like something that you sort of put in and then live with it after you know, to support your heart like a like a manmade equipment, but yes. Yeah, that is that is quite interesting. And yeah, all of these devices and how they sort of interact with heart is is quite fascinating. So we've talked about the monitoring part. And then we've also now you know, talked about the devices which are kind of in my head is like the mid level like during operation and you know, like making maintenance of the heart but what about like the technology available, post an operation or after like we've done the monitoring and done the operation, Or whatever. But, you know, what, what kind of devices are there to support or maintain the heart afterwards?

Abhijit Mondal: 00:28:52

So I need to clarify regarding the defibrillator. So I think what you guys are talking about is the external defibrillator that that the doctor is used. So that is the Yeah, yeah. So that is different than that actual Implantable Cardioverter Defibrillator. So, so I think we should step back a little bit, because I think I might have just gone over multiple places.

Rinat Malik: 00:29:16

No,no. I am actually very interested to know if the I didn't even know that there is such a thing exists, but

Amit Sarkar: 00:29:21

I didn’t know that there is a implantable thing. I always thought….

you're the expert here.

Abhijit Mondal: 00:29:28

Well, yeah, somewhat, I guess it's based on the company here, so the one that you shock and that is sometimes also used in surgery. So once they arrest the heart, I was telling you, right? They use this chemical contraction that they give to the heart, the heart sort of, stays on that rested for a while. And sometimes when they have to revive the heart from beating a lot of patients it just revives but sometimes they have to give a shock and then it sort of starts beating again. So that is basically the fundamental that you just give it a shock and it resets the heart. Now some patients and this is not surgical, this is just patients will have arrhythmias, patients whose heart will suddenly start you know, there will be problems with the conduction or and it will suddenly start creating these random electrical signals in the heart which you cannot control and you will feel, I mean, yeah, if the heart stops beating properly, you will, you will feel that irregularity because of that. So, in that what patients do is first thing, what the doctors will do is they would want to monitor to just confirm the diagnosis that this patient needs this ICD is they will implant they would want to monitor this event, these irregular events, the arrhythmia events that the patient is having, because these are very random, you know, this is not something you go to the doctor and then it's very hard for them to reproduce. So what they do is, there are two things, one, one is what's called a Holter monitor. And this is something actually I went through I don't have deep I was I had some chest pains once which was which ended up being which ended up being basically heartburns which is you know, if you eat something very acidic, it becomes and it keeps you and I was scared, but the doctor basically gave me this whole they put you on this Holter monitor, which is basically it records your EKG continuously for a couple of days. Just to see if you know if it comes back or something so you have wherever you put it on your pocket. There are electrodes placed on your heart, the regular electrodes on two sides here and a few here and it just record your EKG for the whole day and then they see if you know if there are any irregular beats or any irregular signals. The other and but this whole thing is like a huge chunk of like, you know, it's like a Walkman that we used to have I remember and you have to you can't take it off because so they give it to you for a day or two usually. But if it's if it's for longer if they want to record for longer durations of time, what they do is they implant with you what's called an implantable loop recorder, which is basically this really small, pen sized, I shouldn't say pen size, but may be pen diameter size device that they sort of inject or I shouldn't even say inject it sort of they make a small incision on your chest. a really small one and then just inject, place it superficially not inside basically into your skin and then just seal it off. And that has a sensor and a recorder. It's called the Loop Recorder basically so it basically records the heart's electrical activity and electrical activity. It can record up to an hour it can maintain it's got a really small memory, but it basically if it detects senses, any arrhythmia or an irregular activity, it starts recording it. It also comes with this remote or a switch that the patient has and they can sort of you know, keep it in their pocket or tight you know, keep it around their neck. And if the patient himself feels uncomfortable and he thinks some sort of event is occurring he can tap on that and record that event. And then and then they come up come with I think you can directly record report to the doctor or it comes with a pairing device. It sort of sends the data to the to the doctor. So those are arrhythmias and this is purely a conduction problem. So like of the conduction system, you know the heart starts behaving like the electrical activity starts behaving irregularity. And the way and the and the way they have they have thought of is just shocked the heart it fixes it. It just resets it. So, you know patients can be ,They're having beers, you know, they suddenly start peeling and it just shocks them and to step back. So and by the way, the voltage

Rinat Malik: 00:34:06

is like turning the computer on and off, right?

Abhijit Mondal: 00:34:08

It's sort of yeah, you can think about it like that. And the thing is, when they give the when they use the defibrillator as they shown the doctor subcutaneously it's like from the skin, you have to give a higher voltage and that is you know, you when you're shocking the patient at that voltage it's sort of I mean, they will be in pain, you will feel the shock. But when you have the implantable defibrillator, the amount of shock is the voltage is much less and definitely not as painful. Yeah, so that's

Amit Sarkar: 00:34:41

SO, Abhijit, when you talk about these implantable devices. So there is a way to put them in. But then how do you take them out? Do you have to go to the doctor again and they take them out? What about the cell? Say every device medical device will have a battery or something to power them for sometime after the power runs out, they have to remove it. So how does all that work?

Abhijit Mondal: 00:35:03

Yeah, so that is, so that is one of the problem is people with implantable cardioverter or pacemakers have usually so for pacemakers, I know a battery can last anywhere between five to 10 years depending on you know, how much I mean depending on actually how much pacing what this threshold voltage is. There like couple of parameters when they are setting these devices. And in terms of your defibrillator, I guess the more the problem with defibrillator is the shock is a little bit higher voltage. So it uses more so the more arrhythmias the more incidence of these arrhythmias this patient is getting. The more quickly the battery will get used. But these defibrillator and pacemakers, they have, I mean, they have switches and alarms and there are actually all these devices come with these. These remote control transmitter so like, these patients have these bedside I forgot the word,but these bedside monitors that go with these devices, when in the end of the day, when they when they are going to bed. The device usually sinks the data from you know the status of the device and that is sent to the healthcare provider. Via Yeah, wirelessly. There's usually like a cell phone, a separate wireless connection for that it's it does not go via Wi Fi by the way. It's a separate service, it's directly transmitted to the doctor and that is how actually what's called remote monitoring of these devices by the doctors. So if they if they see anything alarming, anything changes, they can then call the patient and make the updates. But so we actually are group recently and I'm sort of finishing that study, we are trying to assess, you know, what is the cost of the of maintaining these devices and patients with pacemakers, and in our case, because we work at Children's Hospital so my boss here is a congenital heart surgeon and some of his patients who are all kids, they need a pacemaker at like this small age. And you know, and you have to they have to maintain, I mean, the pacemaker itself. You have to come up with checkups annually or by annually to see everything is alright or not. But there is a cost associated with that right of just managing the pace maker that's in you. So the two main problems and there are multiple problems. One of them as you mentioned, is the battery. The battery does deplete with time. And so the device the way the pacemaker is, is it's got this. It's basically it's a small, it's called a can basically how they call it it's a can. It's the pacemaker and generated which contains the battery and the electronic circuit. And it's got these leads basically that come out and are implanted either in the heart depending on how they are being placed. So if they are the common way of pacing permanent pacing is what you call transvenous pacing. So what it says is basically the leads shock from the inside the heart. So the press the procedure and the way to do it is and they basically implant take the lead through a transplant procedure through your one of your arteries or not arteries or one of your veins to reach. It basically sent through your small hole is made from which they introduced the lead and guide it using a cat procedure and guide it so it goes and then it's tiered to go through your right atrium, through the cables into the right atrium. Through the tricuspid valve and then it's sort of plunged into the apex or the end of the right ventricle side. So the cable the lead the wire is going all the way from your right atrium going straight down to the apex of the heart or the bottom layer of the ventricle and that is where they send the pulses which sort of contract the. Well which is what basically excites the ventricles for pumping. So that is what they do for the pacemakers. And then it depends there are modes of pacing if you just need the ventricles to be paced, then only one lead is placed. If the atria also need pacing, they'll put a lead other lead that can go into the atrium it right atrium as well. If dual ventricular pacing as required another lead is send into the left ventricle. There are some complications where patients need dual ventricular pacing as well if Yeah, pacing issues.

Rinat Malik: 00:40:03

So I have a question regarding the power of pacemaker. He said, You know, the pacemaker battery could last five to 10 years right. But then again, there was another device which you said with a small incision and then that lasts only for an hour. But they're both very small devices. Why can't the same kind of I mean, does it require more power? Is that why it lasts less time?

Abhijit Mondal: 00:40:30

No. So first of all, the devices are very differently size, so your pacemaker the size would be I would say somewhat smaller than your mouse. It's not as thick. It's a thinner it's a thin device because it just stays under your skin here.

Rinat Malik: 00:40:48

So this might make you think of another way so why Can it…. Is there a way so I'm just thinking of ways to not have to replace it at all after five or 10 years. So is there a way like when the heart is pumping the blood that's like a flow of blood is going can it like generate its charge itself with mechanical device for example. So it never requires replacing after five/ten years?

Abhijit Mondal: 00:41:18

Well? Yes, there is research going on that there is no commercial device that I know. But so the way it works is that the pacemaker itself is not implanted on your heart, the battery and the generator stays somewhere away. From your heart. And it's actually right below I think the left side just below I think it's called the…and I forget the muscles name, but it's right on top of your chest here somewhere where they put it down there. It stays safe there. And it's just this lead. I mean, which is basically wire which is going and pacing giving the shocks so yeah, it's an interesting thought I think people are working on that concept but there is no so far nothing viable has come up. And so I was telling the I mean earlier when I was saying the battery replacement thing. This is more of a pediatric patient problem for children because you know, they have just started lives they have to live for decades now. So for them, this is a big problem. But if you look at usually patients who get pacemakers are really old people, elderly people, and for them you know, they are not very if they are not very mobile or not into very high intensity workout or any sort of exercise. Yeah, very high. Cardio lifestyle is not there. Their pacemakers will probably end up maybe, yeah, eight to 10 years is a reasonable time for them. But it's I think it's basically dependent on the battery technologies, right. So I think now as battery technology is condensing more, you have electric cars, which can go much longer. And in terms of pacemaker In fact, I think Medtronic has one of these really small pacemakers they have invented. I'm not sure if it's still getting implanted or not. Which, which gets rid of the whole leads, you know, right now, it's like the scan with this long wire that goes all the way through your veins and then enters the atrium and then through the valve. By the way, this lead actually touches the valves. So, in fact, this lead can cause eventually one of the complications is, it can cause blockage of the valves or dysfunction of the valves over time. Because you know, the valve completely is always hitting this. This wire which is not supposed to be there. So, they have come up with this really small device, which is I think, a couple of centimeters long and maybe comparable to the Loop Recorder even smaller than the loop recorder which can be implanted right at that, that junction at the end where in the in the ventricle and the end with the near the apex. So you don't need this whole long lead that's going and sitting there. But it's again, it's still not something that's I guess, I'm not sure if maybe it's still in the trial phases. I'm not aware of it being calmer again, available to patients as of now. But yeah,

Amit Sarkar: 00:44:23

So Abhijit, like you mentioned about the arrhythmia and like diagnosing and monitoring them inside the body and outside the body. By giving them a shot, but that is mostly to do with the electrical aspect of the heart. What about the mechanical aspect like suppose there is a pressure drop because of a hole in the heart, or the oxygen and the oxygenated and DD and the deoxygenated blood are getting mixed more. So for those kind of like mechanical issues, what kind of devices are then used inside the body? Say a lot of people have these blocked arteries, what do what kind of devices are used to fix those kinds of cardiac issues?

Abhijit Mondal: 00:45:08

So yeah, blocked arteries. I think it's like the most common and common form of these is called the, what we call the coronary artery disease. What's it called? As it's called so and what are they so the coronary arteries are basically the arteries that are coming from the aorta and basically giving blood to the heart itself. And if those get blocked, your heart will stop functioning and you know, your heart tissue will stop getting the nutrients and the oxygen and blood for it to function itself. There are mainly two main procedures all you know, one is the angioplasty, which is again, that transcatheter procedure where you don't need to do surgery. All you do is you get access to the to the artery from one of the femoral arteries on your leg and you pass what you do is you basically send a balloon there to the blocked region and you inflate the balloon and try to see if it clears the blockage or not. If so, first they try what's called the angioplasty which is just go send the balloon, expand the balloon and see if it unblocks

Rinat Malik: 00:46:16

does it not sort of bursts the artery? Because if you're expanding the balloon, would it not, like reach the limit of the artery?

Abhijit Mondal: 00:46:27

Yeah, so there's that. So that's why it's not a huge balloon. It's the balloon size. They have sizes of different balloons so you pick an appropriately sized balloon and then and all this is done via an under x-ray. So they are doing this radio in this through X ray, they can see where the balloon is moving. In fact, before even they go into the balloon, the way they detect these blockages by injecting radiopaque dyes. So you can go to this place. Inject this dye through the extra they can see you know there is a blockage there or not. And in the same way, they will then remove that sort of guide the catheter they're sent the balloon try to expand Yeah, it's a very small balloon and that's why the balloon always does not work. So and that is when you know it's the balloon will expand but the blockage will not clear. So

Rinat Malik: 00:47:20

So I mean, that makes me think what happens if it's just from a completely different perspective outside of med tech may be a very stupid question, but what happens if you just make the patient like do physical exercise or run so the blood flow is the pressure is so much that you don't even need the forces through the block? Whatever is blocking the artery?

Abhijit Mondal: 00:47:42

Yeah, I don't think that works. In fact, once I mean the blockage, the nature of the blockage, the way it is, you know, it's basically build-up fat and cholesterol. That's what you hear. So it's sort of inbuilt in that tissue. And it might. Yeah, I don't think the coronaries will develop that much of pressure. Because these are like the coronary arteries are really small there. So I don't think that is a viable way of doing it. It's what it's doing is yeah, the pressure increases of course when you when you're doing these exercises, when you're doing it says but it's not enough to Yeah, sort of thing is, I think is yeah, not enough to clear the blockage and also when you are by the way, when you are doing the exercises, you're also increasing the load of your heart, which if it is blocked the artery you know, the coronary artery blockage will stop blood from going into the heart and meeting that limit itself. So you know, it's somewhat like Yeah, and infact that's why you know, when the first symptoms of these blockage our patients feeling dizzy, or having pain when they do somewhat, you know, climbing steps exercises that require slightly more cardio, which is more cardio-intensive, I guess. So I think the primary thing they tell us when you're climbing steps, so you know, it requires the start feeling or when they're trying to walk briskly, they will see the pain on the left-hand side or the left arm or the or the back. So that is not a viable way. I don't think there are any drugs. There as of now. The main treatment doctors give us they give you a blood thinners so that blood will flow more easily. And that's kind of the treatment they Yeah, even after the stenting the place the stent. The stent expands and sort of clears it up. And then the stent basically gets embedded in that region. And that's what sort of maintains the patency it just happens in it. Yeah, it the and if even that, if that gets blocked, then you have the cardiopulmonary bypass, what is called graft systems where they take a vein from your leg, and then they bypass that particular coronary artery surgically so you have an open heart surgery. They sort of saw in the pipe or through the vein, the new vein, put it in the region around the block and then that that sort of works. Yeah. clears out the blocked area because it will, if you don't treat that, the heart itself will stop getting oxygenated or the oxygenated blood or the nutrients and that part of the heart will fail.

Rinat Malik: 00:50:38

What happens to the to the leg without that part?

Abhijit Mondal: 00:50:44

Well. the leg heals, eventually it heals heels, but it's so one of the things I noticed and being in the clinical environment is you know, doctors have to assess you know, which is the best bad option for you. So, you know, which option is you know, here which will not, you know, so yeah, your leg will hurt for a bit. Definitely. But on the bigger side, you know, the bigger risk of your heart functioning is like, is completely Yeah, your heart will function and the rest of your body will function because of that. So, so they have to pick and that's how they outweigh. In fact, you might have heard like in some of these cancer patients, not hard like you know, when they are giving chemo like this is something that comes up. They assess what the quality of life of treatment would be, because sometimes what happens is, you know, yeah, you're alive, you're getting this treatment, but your life is just miserable just because you're always in pain. So, this is something doctors have to judge and discuss with their patients, you know whether they should go with the treatment, but the patient's life is just terrible, or the sleep the patient as it is, but yeah, it's something I've seen doctors here discuss

Amit Sarkar: 00:52:02

Interesting. So Abhijit, so we discussed the aspect about blocked arteries What about like the incorrect mixing of blood, oxygenated, deoxygenated? And then say, you talked about congenital which is basically birth defects inside the heart. So when you have a birth defect inside the heart, maybe an incorrect maybe a chamber is not there. Maybe there is a hole in the heart. What happens to those kinds of problems and how they are fixed by those cardiac devices?

Abhijit Mondal: 00:52:33

So, so congenital, the field is called Congenital Heart Disease. So it's basically children who are born with defective hearts. And normally usually, I shouldn't say normally the majority of these defects are structural defects. There is also congenitally complete heart block, which is, which is a conduction defect where there's the conduction, but usually, it's some sort of structural defect it could be associated with the valve or there could be associated with I think the most common ones are associated with the septum where you know, so the septum is the wall that divides your left and right side of the heart. And because your right side carries deoxygenated blood, the left side carries oxygenated blood. And in terms of so congenital heart disease itself, sort of is divided into what's called cyanotic and noncyanotic disease. So cyanotic means like there is a severe problem of mixing up the blood deoxygenated oxygenated blood and what do you call you know, it has to be treated immediately. Because if you don't, your body you know, when you're a baby, you your circulation is very important for your development. So and if your body is unable if you're unable to send oxygenated blood to all the different parts of your body will not be able to Yeah, it will affect your growth basically and you will not survive some of these patients actually, if they are if our doctors don't go and surgically intervene and do some sort of palliative surgery which sort of temporarily fixes the problem a child I mean the child can like you know, will not survive like seven or eight days even. Because, you know, the organs are not getting the nutrients it's just fatal. The condition could be fatal. The more simpler ones are the septal defects. So, there is the atrial septal defect. So, there is a hole in the atrial walls. So, there is somewhat slight mixing between the between the atrias, usually that is something that's not required immediate surgery. The most common way of the septal defects is through surgery where the patient is put on the table, we put the they will arrest the heart, go in and then patch it up with what we call some sort of tissue. Not tissue, it's grafts usually there are standard commercial grafts that are available or they actually use what I've seen here and children's they use is they use the pericardial sac material. So if you know the heart actually sits in, engulfed in this in this pericardium it's a bag it's basically a sack in which your heart is so when they operate they actually have to first cut open the sack and then there is the heart. So they use the sack material itself. They will cut out a pattern based on the holes the way the hole is and they just go there and just suture it in that hole. And what happens is when they suture it back up the heart pack becomes you know, it's starts to pimp back eventually, you know, it's just fibrous tissue grows over that path. So it just which is like the nature of the body you know, any foreign body you put in the body, eventually it will send some sort of foreign body response is to go and cover it up with fibrous tissue. So it just covers it up and then the patient Yeah. I mean that there is no mixing of the blood. There are a couple of Transcatheter devices instead of going through surgery. There are a couple of devices for closing these holes as well where you know, same catheter they will take go from the femoral or one of the other arteries and get into the heart atrium. And then usually I think it's used for atrial septal defects. The If the hole is in the ventricle, it's a little bit more difficult to reach and do these procedures. So they have to do surgeries. I don't I don't recall anyone you doing for ventricular septal defects, but so they go and yes, we it basically goes there is the device is sent in and navigated to go towards the atrial walls. So it goes through that through the hole in the atrium, sort of creates this expand it expands and creates the slight wall. It's pulled back and then sort of on the backside it creates another walls and it contracts and sort of closes the hole from both sides. So that is the most common but there are not many devices. It's so far as I know it's still this is the only device I've heard of. Or I have seen but again because I'm I work with a surgeon I've seen him mostly do surgeries and do these repairs. And I remember so from just from the beginning of the podcast when you mentioned about the colour of the skin, right? So this is one of the big one of the cyanotic diseases it's also like commonly known as Blue Baby Syndrome. I don't know if you have heard so basically what happens is because the blood there is the body is not getting oxygenated blood and you guys know deoxygenated blood is actually slightly bluish. You're so the baby's basically the skin turns blue. And that is yeah because of the colour of the blood is not the blood is not going to red. The occipital blood is not going anywhere.

Amit Sarkar: 00:58:21

So I think recently one of my wife she knows a mother and whose baby had to be taken to the hospital because she actually turned blue. He has a asthma, genetic. So right from birth, she has asthma and she had he or she so because of that her body was not getting enough oxygen. And so it's not related directly to the heart but just because you're not getting enough oxygen you the you start turning a blue, so they had to give her like the inhaler. So to fix this problem, but yeah, it's really scary actually. For to see your own child going through so much pain and at such a I mean you think that okay, when someone is born, they're perfect and everything will be fine. If they are healthy. They'll heal quickly then recover. But then when you see and hear about all these diseases and genetic defects, then you start worrying quite a lot.

Abhijit Mondal: 00:59:24

Yeah, and especially like the cyanotic congenital heart disease which are considered complex. The thing is, I mean, the most basic way of thinking is you know, and as I was taught in our school is the size of your heart is considered the size of your fist. And you know, think about the surgeons complicated surgeons ability here like, you know, he has to I mean, what a kid how small I mean, it's like a smaller than a strawberry shape and size and the surgeon has to figure out how to go and correct these structural defects. So I think one of the things so in these more severe congenital heart diseases one of the approaches is to do surgeries and stages. So they can actually do because the big problems here also is that the heart is continuously growing right now. Right? The baby is born the first 10 year I mean, basically from year one to year 20 Your heart is keeps growing, basically. And in kids especially the rate is much faster for the first 10 to 15 years. So any sort of you cannot you know, you don't have the option of to implant any device at that age because you have to account for the growth of the heart itself, especially for these cyanotic babies with cyanotic congenital heart diseases they have to what they essentially do is and in the most simplistic term is the change the modify the plumbing of it, of the heart, so that you know, they are bypassing so I guess the strategy is called a palliative approach. So what they do is they are not exactly curing the heart disease, but they have made some modifications so that the body still gets the whole the blood, the oxygenated blood is sort of transported to the heart everywhere. So they will make change make changes to the way the arteries are placed. And you know, so the blood is applied and the baby keeps growing and you know, the child is growing and then once he is like grown to like four or five years as is appropriate size for them to conduct a surgery. They will then go again the child will again have to be brought back and then they will make further modifications to the heart and then so that for the next few years, the child can again grow. So yeah, it's sort of I mean, from an engineering aspect, you know, you have to think this biomedical engineering, you know, it's come up more in the last 15 to 20 years, I would say like maybe 10 to 15 years. But like before this it was all these doctors were doing all the things sharing, trying to figure out you know, how to get these patients to live by just changing the plumbing or mechanical aspects to the pacemaker and defibrillator these were again, devices that were discovered by cardiac surgeons. The guy forgot his name. But I think Walter Lilly comes to mind he's one of the pioneering heart surgeons, under whom well, who have developed this bypass system they were competing doctors and on Patea. I would also like to just mention a lot of these modern cardiac surgery techniques, especially like the ones that are done in adults have been developed by actually congenital heart surgeons, surgeons who have been working on kids trying to fix these congenital heart defects. So the whole cardiopulmonary bypass and the Pacemakers were all originally developed to treat children first. But I mean, the market size was much smaller. So it's you know, it's all gone into for adults.

Amit Sarkar: 01:03:25

This is so fascinating. Right Rinat? What do you think?

Rinat Malik: 01:03:30

This is. I mean, I'm amazed that you know, what you get to see as you know, as part of your work and such like a critical you know, life-altering situation that you are experiencing for other people every day and it must be really rewarding for you to sort of experience and be part of that as well. And obviously, to working towards something to improve the overall outcome in future. So, tell us a little bit before we finish, but I am curious to know a little bit more about your current research that you're working on and what are you trying to achieve?

Abhijit Mondal: 01:04:08

So certainly, one of the projects that I'm currently involved in and which actually gets me some clinical exposure into the OR, which has to do with intraoperative conduction tissue identification. So as I mentioned, so my PA here, Dr. CASA, he's a cardiothoracic surgeon goes and corrects these surgically correct surgically corrects these congenital heart defects. So one of the problems associated, you know with these surgeries is damaged to the conduction tissue, the you know the electrical system of the heart. And one of the big problems is you know, you sort of know where the conduction tissue is in normal hearts. But you have very little I mean, you only know approx you know very little about where the conduction tissue is going to be in defective hearts. And as they are and the thing is, some of the regions where they actually do these repairs, they, they end up the conduction tissue sort of ends up being close to that region. So when they go to fix something like patch things up, apply suture or cut things, they end up damaging the conduction system. And what happens is once if they damage it, they have to these patients basically end up leading pacemakers basically for the entire life. And it's, it's, um, it's a huge there's a huge cost associated with, you know, managing this living with pacemakers. And then it's a big problem for this kid as well. Living with a pacemaker managing it. With it, so what I work on right now, as we do intraoperative imaging, mostly what we use is what we use intraoperative microscopy basically, I would say, So, what we are using as, as what's called a fiber optic confocal microscope. So let me just break that down about so when you think about a microscope, right, you think about these objectives, huge objectives, there is a table you're looking at from you know, with the eyepiece and all. So fiber optic confocal microscopy, is basically you can think about a fiber optic cable like it's a thin 567 cable. So it's basically a microscope at the end of a thin fibre optic which you can use your hand to maneuver it and use it during surgery to look at microscopic structures. So you know, you can do live microscopy while you're doing surgery, essentially. And so what we are trying to do here is and that's the story the way it goes. Is part of it was developed on the bench by some of my colleagues, my colleagues in grad school, who found out that the conduction tissue resembles a certain has a certain type of tissue architecture compared to your regular heart cardiomyocyte architecture. So, we are basically trying to translate this technique of using this fiber optic confocal microscope towards identifying where the conduction tissue is, when they when the surgeon is operating. And if we identify correctly, where it is be avoided. So yeah, basically we have this microscope, we have this microscopic knowledge of the microscopic structure of the conduction tissue. Which sort of lies right below the walls of septum and it's called the epi epicardium, which is the layer of the heart, the top and just enough depth that we can grow and image below the tissue. Enough from the top superficially and identify these structures. So for the surgeon is of great value like you know if you know where this sensitive tissue is, which if you damage can cause this additional problem for this patient, you know, you can then avoid and that particular region and you know, sort of make the strategy of the repair in such a way that you don't perform that surgery. So and then sort of it reduces one of the problems of for the patients after the surgery. So we are doing so we were doing I was involved in this trial, where we would identify and try to see in these patients and then see if these patients end up with any conduction problems. So a lot of my work or part of my work is basically you know, moving these technologies into the clinic, and aspect of it, which is you know, I would say sort of motivates me here. You actually get to see these technologies being used and sort of avoid. Avoid conduction tissue damage. The damage to the patients. So I was involved in that trial, and then we do some animal. So any sort of medical device development by the way, is always started with the small animal model in rats. Then you move to a large animal model which is you know, could be pigs or sheep and then they move to humans. So in this project, the rat aspect, the small benchtop small animal aspect of it was done by one of my colleagues, grad students, and then I was involved in doing these larger animal studies. And then and then the clinical trial and the patient. So I would basically go and help set up the device in the OR, and then it's a microscopy image. So I would actually interpret sometimes help interpretation of these images and you know, what is conduction and what is not. And then the surgeon would confirm and decide accordingly. You know, whether he wants to operate here or make some changes to the operation or not, or modify where he wants to operate. So, yeah, that was interesting for me. Yeah, I had never been to an OR like, just to get to see all that that was. That was sort of amazing, I would say,

Rinat Malik: 01:10:19

Wow! No, that does sound really critical work. As well as quite amazing. To be part of it and contributing to it.

Amit Sarkar: 01:10:29

I have one last question for you Abhijit before I finish, and that is related to stem cell research. So, I mean, there are all these congenital issues with respect to the heart, and there is a lot of research going in the stem cell world where you want to create any cell from stem cells. So are there any many areas of active research going on that you are aware of? That can help with these congenital heart diseases with respect to stem cells?

Abhijit Mondal: 01:11:06

That is, I'm not aware of any. Yeah, not with respect to congenital heart diseases. So the problem with congenital heart diseases it's more because of during development, I mean, delivery development of the fetus. Yeah. So some of the you know, so the thing is all the congenital heart disease we don't know how these are cause some of them are genetical, some of them are associated with certain drug use. So I think some of the if, if the mother does drugs, a certain are exposed to certain drugs, or they do some drugs, there's some of those effects associated with that. But stem cell. I think it's mostly stem cells have mostly been used for therapies. And what we deal with here and congenital heart disease is more. I mean, it's more a structural defect, it's already there. And the only way to, or the most viable way is to go and surgically fix them. So yeah, it's I'm not aware of any direct stem cell therapy with congenital heart disease yet, but that particular

Amit Sarkar: 01:12:21

Okay, no, thank you so much. Again, I think we had we have covered lots of aspects today. So I just wanted to summarise what we have talked about today. I hope I can do justice. Because you've spoken quite a lot about various things. I think we started about what the heart is the different chambers what its function is, we talked about the mechanical aspect and the electrical aspect of the heart. Then we talked about the monitoring like how do you monitor the blood oxygen level, the pressure, the heart pulse, or the beat or the heartbeat? Then we talked about the various electrical issues that comes with the heart like arrhythmia and then how do we treat them using different types of devices and then we talked about the different mechanical issues, which is related to the blockage of an artery or the mixing of the oxygenated and deoxygenated blood, or there are some other heart defects and so finally, we covered about the congenital heart diseases, so kids who are born with heart defects, and then the surgeons that require and I think the last bit was your area of research. So I think it was quite comprehensive talk Abhijit and thank you so much for your time. Today. It was a real pleasure talking to you and I hope our audience has found a lot of useful information from the stock.

Rinat Malik: 01:13:47

Yes. Absolutely and Thank you very much Abhijit again, from myself. I feel like we've asked you so many questions and made you talk a lot, but hopefully you enjoyed the conversation as well, to have keen listeners, and I'm sure our audiences also keenly sort of enjoyed this talk and if you guys have any questions, please reach out to us and we can also direct questions to Abhijit if, if necessary. Yes, please do reach out or actually also share with your relatives and loved ones that someone might be who is interested in in medical medicine or medical technology, etc, etc. So I feel like there is a good insight or good look into the life of a person working fearlessly in the medical industry and you know, generating a lot of value. Thanks again, Abhijit, once more and audience we look forward to coming back with you again next week with another episode. Until then, thank you very much,

Amit Sarkar: 01:15:01

Bye, everyone.

Abhijit Mondal: 01:15:03

Bye, Thank you!