October 2015 – The Student Physiologist

How Is Your ECG Electrode Placement?

As a student cardiac physiologist it has been drilled into our heads from an early stage the importance of correct anatomical electrode placement in obtaining an accurate ECG recording. An ECG measures the electrical activity of a patient’s heart from many different angles, and is achieved by placing 10 sticky electrodes on the patient; four on the limbs and six on the chest. For correct electrode placement we follow the clinical body guidelines set out by the our governing body, the SCST. As specialists within the field, we have a duty to perform these tests in a standardised, methodical manner to produce reliable and accurate diagnostic information, as the ECG is the first port of call when assessing heart abnormality.

Unfortunately, from my experience, and from that of my colleagues, the misplacement of these electrodes has become somewhat commonplace. To the unassuming operator this may seem superficial but incorrect placement of electrodes can alter the ECG patterns displayed simulating or concealing abnormalities, such as myocardial ischemia/infarction.

There is evidence that many health professionals who record ECG’s have not been suitably trained or assessed in the technique: A study by Kings College London into electrode misplacement highlighted that only 50% of nurses and less than 20% of cardiologists correctly place leads V1 and V2 during a standard 12-lead ECG. These numbers are quite shocking and highlight the widespread misunderstanding of this key diagnostic tool.

Close0up — An example of how NOT to perform an ECG. V1 and 2 are incorrectly placed, as are 3 and 5.

I personally witnessed an example of this whilst on my first week of placement. I was performing an ECG on a patient within the cardiac ward under the supervision of an assistant technical officer who regularly performs ECGs. I correctly located the anatomical landmarks on the patient’s chest and applied the electrodes, as per the official guidelines. At this point, the ATO interrupted me and challenged the placement of my V1+V2 electrodes, stating they were too low. She then took over control of the procedure and removed the electrodes. She began to count the intercostal spaces, beginning from the clavicle. The guidelines state the operator should identify the manubriosternal joint, or angle of Louis, on the patient to locate the second intercostal space as their first anatomical landmark. This subsequently meant her V1 and V2 electrodes were placed too high and my original placement was in fact correct. After the procedure I challenged my colleague about this explaining we were taught to follow the SCST guidelines in our electrode placement. The ATO responded by saying that this was “how they had always done it.” I discussed this with my clinical educator and the issue was later addressed with my colleague.

The consequence of incorrect ECG recording can lead to potentially incorrect diagnoses and inappropriate treatment leading to wasteful use of healthcare resources and even cause harm to patients. Evidence suggests that adequate training of operators reduces ECG recording errors. However as the SCST highlights in their guidelines, the indications there is little awareness in many practitioners of the need for training.

Clearly, the solution to this issue is to increase awareness in health professionals exposed to ECG practice about the importance of correct electrode placement. This could be achieved by increased collaboration between cardiac physiologists and other healthcare professionals. As specialists within the field we have duty to share our expertise and knowledge to ensure our patients receive the best standard of care. As a profession we should be much more active in teaching and increasing awareness of what we do and why it is so important. Relevant staff should be confident in performing ECGs not because of experience, but due to high quality training and continual auditing.

To achieve this I feel our profession needs to embrace this responsibility and be far more active in the support and training of other health professionals.

Khunti, K. (2013) Accurate interpretation of the 12-lead ECG electrode placement: A systematic review. Health education journal . 73 (5) pp. 610-623.

Harrigan, H., Chan, TC., Brady, JW. (2012) Electrocardiographic Electrode Misplacement, Misconnection, and Artifact. The Journal of Emergency Medicine [online]. 43 (6), pp. 1038–1044.

Baxter, S, Blackman, S, Breen, C, Brown, C, Campbell, B, Cox, C, Eldridge, J, Hutchinso, J, Rees, E, Richley, D, Ross, C. Society for Cardiological Science and Technology (2014) Recording a standard 12-lead electrocardiogram. Available from: http://www.scst.org.uk/resources/CAC_SCST_Recording_a_12-lead_ECG_final_version_2014_CS2v2.0.pdf

http://millhillavecommand.blogspot.co.uk/2012_05_01_archive.html

Have You Ever Tested A Robot? Pt II

I still haven’t.

Bear with me, though, as this is going somewhere, I swear.

After the last session, in which I provided the robot’s voice and controlled its HR and ECG, it dawned on me that as a result, everyone had the opportunity to be filmed performing the test and gain valuable group feedback, except me.

I wasn’t the only one to notice this, as it transpired.

During a subsequent lab session, wherein we practiced manual BP, honed bedside manner, discussed contraindications and compared different methods of BP measurement, it was revealed that the remainder of our ECG feedback period would be completed in the lab. We no longer had immediate access to the simulation mannequin, so thanks to a willing volunteer, another of my colleagues was able to complete the procedure and again receive feedback in a partitioned area of the lab.

Then it was my turn to step up to the plate.

I was the last to ‘go’, as it were. The difference between my assessment and the other’s lies in that everyone else enjoyed an element of seclusion: the curtains around the bed-space being pulled in the first session and the high walls that separated one section of the lab from the other, in the second. The rest of the group stayed outside of these boundaries in everyone else’s case. Not for me, though. I stood away from the couch, preparing to make my entrance to the imaginary treatment room I could see in front of me and just before I could open the invisible door, the consultant physiologist taking the session said “Wait, I’m just going to call everyone else in, if that’s ok?”

“…If that’s ok”, as if I had a choice.

Everyone else filed in. They kept filing in for what felt like an age. My lecturer, the rest of my class and the head of physiology. Then, they all looked at me, waiting.

I’m not sure how I’d have fared if I’d known this was going to be the format for my peer assessment, but I feel no shame in admitting that I don’t remember ever being as scared as I was before I started moving. I didn’t know how to begin, so I just went for it. I walked into the ‘room’ (after, somewhat embarrassingly, opening the invisible door) and performed the test as I would out on placement.

I asked all the required questions and added one or two patient identifiers to account for the fact that I didn’t call my patient from any waiting room and gained a consented, accurate trace.

Not only did I do it all with the eyes of more than a couple of people scrutinising my every move, I did it with a piece of equipment I have never used before and the most tentacle-like cable configuration I’ve ever seen in my life- if you’ve tried to untangle the wires behind your television when you’re moving house, you’ll know what I mean but, trust me, this was worse. In addition, I managed to ignore a completely new experience: the fact that I was so scared that the back of my neck was sweating..!

Fear is natural. It’s normal to be scared of doing something that’s relatively new to you, especially when you know you’ll be watched and judged doing it. Whatever ‘it’ is, it wouldn’t feel like a real achievement if we didn’t feel fear beforehand. I’m glad it was sprung on me, if I’m honest. My final assessments and various practical examinations for the rest of my career will follow this format so it’s good to have a grasp on some of the emotions I’ll be feeling before them. If you’re just beginning the PTP programme, you’ve got things like this to look forward to, so just try to enjoy it. Realise that the fear of these things is normal and, most importantly, the sooner you take a deep breath and swallow the lump in your throat, the sooner they’ll be over!

Thanks!

Hydrogels As An Alternative To Reperfusion And Transplant.

“Cardiac failure is a critical condition that results in life-threatening consequences. Due to a limited number of organ donors, tissue engineering has emerged to generate functional tissue constructs and provide an alternative means to repair and regenerate damaged heart tissues.”

Such is the sentiment from Ali Khademhosseini and a team from Massachusetts. In fact, they reported here, that in 2009 an average of 77 U.S. citizens underwent transplant each day, but 20 died as a result of a lack of organ availability. The aim, then, in the absence of treatment, is to repair the damaged organ in-situ so as to negate the need for transplant at all.

Enter hydrogels.

Hydrogels are already used in the regeneration of a variety of tissues, and combined with some of the brightest minds in the field significant advances are being made in regenerative medicine: in May this year a team in Toronto have successfully repaired brain tissue after stroke and partially reversed blindness. These versatile substances are also used in disposable nappies, silica gel and contact lenses, so there’s a high chance you’ve already been exposed to them without even knowing it!

These polymers exhibit many desirable characteristics in regenerative medicine. They are relatively easy to synthesise, they can act as solute transports/drug-delivery systems, exhibit elastic properties as well as preventing thrombosis. Their structure also enables them to create a “scaffolding” for cells.

This last point is crucial when combined with the hydrogel’s other properties, but I’ll return to that shortly.

First, consider what happens to cardiac tissue after an acute myocardial infarction: during infarct, the oxygen supply to myocardial cells is reduced or diminished, causing irreversible cell death and necrosis around the occluded artery/arteries. The scar tissue that takes the place of the once-functioning cardiac muscle has none of its contractility and the heart is far less efficient as it once was. Cardiac output, systolic and diastolic functions are affected and whilst medication, reperfusion techniques a bit of luck regarding preserved left ventricle function all provide a better prognosis, heart failure is a serious risk and figures regarding mortality rates aren’t great: MI, specifically STEMI brings with it a 30% mortality rate, 50% of this figure dying before hospital admittance and 10-15% being re-hospitalised one year after the index event.

So, where do hydrogels come into the picture?

In the case of extreme loss of cardiac function and the inability of conventional treatment to improve the given prognosis, hydrogels provide an environment in which it is possible to introduce stem cells, growth factor, gene injection or therapeutic medication in an ‘artificial’ environment that simultaneously provides mechanical support to the infarcted area and aids in the replacement of necrotic tissue. As well as being a relatively non-invasive procedure when it comes to the injection of the treatment, the hydrogels scaffold itself is naturally degraded by the body when the process is complete.

According to another team in Massachusetts, published here, trials have shown significant success since they began in small animals, but their application isn’t as straightforward in large primates. They commenced in humans in 2008 (in an extremely truncated form), but in order for hydrogels to be viable in widespread clinical treatment, much more research is required. An example of this is that not much is known about the exchange of signals that take part in the movement of stem cells to an injured myocardial tissue post-hydrogel treatment. Optimum degradation time is a further issue in humans.

Despite these, and other setbacks, there remains great promise in hydrogels to lower global mortality rates as a result of MI. In recent years, significant advances in research are making the possibility of myocardial repair in humans an almost visible reality.

Thanks!

Light At The End Of The Tunnel

Having being around for a few years now, I’ve read an ECG or two in my time. If you’re still early on the road to becoming a fully-fledged Physiologist though, let me assure you of one thing: IT DOES GET EASIER!

I won’t lie, even with the experience I now have, there are still the occasional strips that leave me scratching my head like a confused monkey but on the whole, a 12-lead doesn’t scare me anymore. One thing that I think many students will find at some point during their learning, is that their more experienced counterparts have somehow forgotten how difficult it is to read an ECG. You might take an ECG for someone to check and receive a reply along the lines of ‘Well, obviously this is…’ Not all that helpful!

Learning to read an ECG is a lot like learning to read a new language. Sure, if you’ve been practicing for a long time, you’re pretty fluent, but it’s important to remember how hard you found it back when it was still just a foreign language to you. Only then can you start to empathise with those who are in that position now. And if you are in that position now, don’t give up!

If I could offer one word of advice to you, the person reading this who is desperately trying to get to grips with ECG, it would be this: get to know what a normal ECG looks like really, really, REALLY well. Then, get to know how that relates to the electrical and mechanical activity of the heart. (I suppose that’s sort of 2 pieces of advice but stick with me here). If you can get all of that into your head, you’re putting yourself the best possible position for progression. If you instantly know what a normal ECG looks like, any abnormality should stand out like a sore thumb. You might not know what the abnormality is, but if you know how the ECG waveforms relate to the mechanical activity of the heart, you can at very least a take good, educated guess on what that abnormality suggests the heart is actually doing. You won’t be an expert, not at first, but you will have the foundations on which you can build and make yourself one.

Therefore, the most important first step is to learn what is ‘normal’ but I’ll discuss that in detail in a later post.

Pacemaker Re-Use For The Developing World

To some of my experienced readers, the fact that pacemaker charities that recycle pacemakers exist may not be news at all, however if, like me, you had no idea, then hopefully this post will make for some heart-warming (sorry) reading.

I was interested in what happened to pacemakers when the user passed away, and after a quick internet search, I found that they were almost invariably stockpiled when cremation was requested, or buried with the deceased. Considering that there are over 34,000 pacing procedures performed in the UK alone, this seemed somewhat wasteful. Knowing that the average life of a standard pacemaker is currently anywhere between 6-10 years, I found it hard to believe that there would not be remaining battery life in the devices when they were no longer required.

Pacemaker research is advancing all the time; Medtronic released their “Micra” (pictured right), which is lead-less and no bigger than a large multivitamin tablet, so with more advances, the price of a standard pacemaker is dropping. The current prices are still out of reach for the people who need them in many developing countries and that’s before the cost of the procedure and hospitals accommodation/ follow up care are considered.

A study at the Hospital of the University of Pennsylvania, led by Dr Payman Zamani discovered that of 27 pacemakers taken from a mortuary stockpile, 8 had a remaining battery life of at least 4 years. This is obviously 8×4 years of alleviated symptoms that are going to waste in this one mortuary alone, and it was estimated in 2011 that more than 1 million people from the developing world died as a result of not having access to pacemakers, so health organisations began looking at ways to reduce this waste.

Companies such as Heartbeat International and Heart to Heart have been recycling pacemakers since as far back as 1994, but in 2013, Pace4Life, a UK company run by Chemistry graduate Balasundaram Lavan began a partnership with the NHS and other healthcare organisations, and morgues to recycle as many viable pacing devices as possible. It’s against EU legislation for recycled pacemakers to be used domestically, but it is well within the confines of European guidelines for them to be taken from consenting individuals and used outside of its boundaries

Pace4Life only accept devices with >70% battery life remaining and during the refurbishing process, all former patient data is erased, so confidentiality is in no way compromised. Their website at http://www.pace4life.org contains a list of studies and guidelines with which they work as well as patient, next of kin and mortuary donation documents to enable people to help the less fortunate gain access to potentially life-saving medical equipment.

I’ll let Lavan himself explain a bit more:

Thanks!

The Best Apps For Student Physiologists

(in my opinion and predominantly found on android)

EDIT: I have added a 5th app at the bottom of the page, “Read by QxMD”.

My bus journey to university can take anywhere from 1.5 to 2.25 hours, depending on how willing the driver is to break the speed limit, so I try my best to make good use of the time available.
It can be rather cumbersome to hold a textbook when the bus is full and the constant movement makes it rather difficult to follow the words on a page, so I downloaded a few apps to help pass the time as well as study and, as you can imagine, some of them have been better than others.
So that you don’t have to spend your wages/student loan unnecessarily, I’ve decided to share those few apps that have either interested me, or helped me during the PTP programme so far.

I’ve omitted any apps that are effectively digital print textbooks, as these are often promoted in both Google Play and the App Store, costing £20-30 and are nowhere near as difficult to find as a couple of these picks.
I’m also not suggesting that you get all of these apps, either; were it not for this post, I wouldn’t have them all. Everyone learns differently, so you’ll probably need one or two at most.

All of these prices are correct at the time of posting, but if any have changed, let me know and I’ll update them accordingly.

1.) ECGsource, Cathsource, Echosource (ECGsource LLC)
Google Play: £1.92, £2.54, £3.03
App Store: £0.79, £2.29, £2.29

These three apps provide a great deal of content and are very reasonably priced, but ECGsource on it’s own is the app that will benefit Y1&2 PTP students the most. It contains information and analysis parameters for a very large number of pathologies, videos to help you understand key principles in ECG science and a tutorial on reading a normal ECG.
This app is a personal favourite of mine, not just for the number of arrhythmias it covers, but for the examples it gives in addition to these.
If you have an android device and you can only get one app, make it this one.

2.) ECG Practical Demo (One 2 One Medicine LTD)
Google Play: Free
App Store: N/A

This app isn’t nearly as easy to follow as ECGsource, but is still packed with content once you know what you’re doing. It also contains a rate/R-R correction tool, a set of digital calipers and an easy to use axis calculator for measurements on the go.
There is a paid version of this app available to purchase, but if you spend a couple of quid, you’ll get all the same information with better quality examples by getting ECGsource or QxMD. For the tools you get with the free version, however, you can check your answers on analysis assignments for free, making this worth a look.

I’m yet to find an app with all of these features on the App Store, but, if I’m honest, I started running out of money whilst wading through the plethora of terrible apps out there, so stopped looking.

3.) 100 ECG Cases for Finals (One 2 One Medicine LTD)
Google Play: Free
App Store: N/A

A quiz featuring (shockingly) 100 ECG Cases for you to analyse and be graded on.
Quizzes are grouped into categories such as Uncommon Arrhythmias, Supraventricular Arrhythmias, etc, so you can really fine-tune your skills in a particular area.
100 ECfF doesn’t offer any tutorials, so obviously it’s recommended that you have some knowledge from other sources before you have a go at it, but it’s made for USMLE finals, so it’s a handy thing to have as you progress.

It isn’t available on iOS, but ACLS Rhythm Quiz is the best option over on the App Store, costing £0.79

4.) QxMD ECG Guide (QxMD)
Google Play: £3.19
App Store: £0.79

Much the same as ECGsource, but seemingly optimised for iDevices, this app has everything a PTP student could need for ECG analysis and arrhythmia recognition. This great app also comes with a handy analysis tool that can you can use to check your answers when you’re practicing.

5.) Read by QxMD (QxMD)

Google Play: Free

App Store: Free

This app is a wonderful way to tailor your journal reading experience to suit your course needs. New updates and articles are available frequently and are all viewable and searchable within the app. I have personally found this tool to be invaluable when trying to further understand the nuances of pathologies within cardiac science.

Hopefully these will help you along your programme as much as they have me.

Thanks!

Are Athletes At Greater Risk Of Pacing In Later Life?

If so, what is the cause?

The Athletic Heart Syndrome isn’t indicative of any pathology in athletes, and although it is theorised that the changes the heart undergoes as a result of training, there exists no evidence of long-term effects. The athletic heart often has a resting rate much slower than that of an individual of a less active nature. This is not uncommon in physical athletes, as it has been reported that Sir Chris Hoy has a resting HR of 30bpm and fellow cyclist Miguel Indurain one of just 28..!

The cause of this is a very active vagal tone, resulting in bradycardia. As I’m certain many of you are aware, this is a condition that would almost certainly (correct me if I’m wrong) require pacemaker intervention in elderly patients, but in the case of athletes, this bradycardia is due to an increased stroke volume which means the required workload of the heart is decreased. All well and good whilst one is in training, but what if this lower HR did not ‘reset’ to within the normal parameters once training had ceased? I don’t think I’m incorrect in assuming that this would lead to the same treatment a non-athlete, former or otherwise, would receive anyway, regardless of any prior level of fitness.

There is in fact a 2007 study by Baldesberger et al, that suggests this is indeed the case.

Published in the European Heart Journal and found in full here: http://eurheartj.oxfordjournals.org/content/29/1/71 it is shown that there is a statistically significant increase of sinus node disease in the tested former cyclists when compared to the control group, in this case golfers.

Interestingly, I have stumbled across a British Heart Foundation- funded study run in part by the University of Manchester, that they feel suggests the increased presence of arrhythmias in athletes is due to molecular changes as oppose to increased activity in the autonomic nervous system.

The study in rodents showed a decrease in HCN4, a protein found in the mammalian SA node. In humans, a mutation in the HCN4 gene is sometimes found in patients exhibiting sick sinus syndrome and in those who display bradycardia, so the teams behind this study believe that if they can replicate the rodent’s results in humans, it will help us understand arrhythmias that endurance athletes often suffer in later life.

The published study can be found here: http://www.nature.com/ncomms/2014/140513/ncomms4775/full/ncomms4775.html

I’ll answer my second question, “if so, what is the cause?” with an obligatory “je ne sais pas”, but it’s clear that we are edging ever- closer to an answer. Of course, whether that answer is due to molecular changes, or nervous ones remains to be seen.

Either way, it is stated by the team at the University of Manchester that although endurance training can have harmful effects on the heart, these effects are more than outweighed by the benefits.

As an added bonus, here is a short video by Sarah Pratt showing some common differences in an athlete’s ECG (in this case the featured athlete is the NHL’s Tobi Rieder *!*) compared with that of the rest of us. Enjoy!

As ever, if I’ve missed anything, or am just plain wrong about any part of this piece, sound off in the comments below and I’ll do my best to rectify this.

Thanks!

Have You Ever Tested A Robot?

I haven’t. That part comes in a few weeks.

I have, however, BEEN the robot in question, as today, I provided the voice and cardiac controls in my university’s simulation suite.
My peers performed ECGs on a rather frightening, dead-eyed humanoid that was, unbeknownst to them and in
conjunction with my voice, being used as a conduit for a scenario pertinent to our learning. That’s me on the right, there, next to my control station (a closer view makes up the header for this post) which allowed me to alter heart rate, breathing rate, create a whole host of arrhythmias and not only see my colleagues, but speak to and hear them as well.

I was a patient named Christopher Smith who had been admitted to A&E. That was all the information that had been supplied, barring my NHS number and date of birth. It was the job of my fellow students to check three patient identifiers, get a brief idea of what was wrong with me and to perform an ECG accordingly, with a brief assessment of the adjustments needed and that of the trace itself.

It was made clear both before and after the session, that it was ok to make mistakes and that this was predominantly what the session was for. It’s extremely unnerving, having a conversation with an expressionless robot that can visibly and audibly breathe, so it was nice to be reassured that the pressure wasn’t as high as it could have been.

Everything going to plan, it would emerge that my chest pain was a result of atrial fibrillation and a heart rate of a mere 32-35bpm. It was also an assessment of how quickly we prioritised the test itself. Due to the presenting chest pains, attaching the limb leads first, so as to gain a visible rhythm strip before a full 12-lead was the correct response, then adjusting the paper speed on the trace itself so as to provide an useable ECG was the next desired step. All the while, I was talking to the student practitioner, asking questions about the test and about the situation in order to see how they reacted and whether they felt comfortable keeping me, as a patient, calm at the same time as carrying out the test with the required level of haste.

These sessions were filmed and then followed a group feedback discussion. The group seemed pleased with the outcome, overall. The comments made were mostly of a positive nature, and the few criticisms there were from myself, my peers and our lecturer, were minor and constructive. This has most certainly been my most enjoyable session to date, and one I did not mind getting up at 4:30am to help set up, so needless to say, I’m very much looking forward to the next one.

I will add that the first half of the session used me as a living mannequin. The reasons that I didn’t comment on this until now are twofold;

It was effectively the same as what I have written about, only without the technology
Seeing my naked torso on film reminded me that I’m still carrying holiday weight. This wouldn’t be a problem, were it not the weight from four holidays.

Thanks!