Category Archives: Electrophysiology

George Mines and the Impermanence of Knowledge

George Mines

It was a chilly Fall morning in Montreal. A Saturday, the campus of McGill University was quiet. Students, not much different in 1914 from those of today, were sleeping off their Friday night activities. A cleaning woman entered the Physiology Laboratory to dust the glassware and wash the floors. As she turned a corner she was startled to see a young dark-haired man, sitting in a chair. She recognized Professor Mines, the handsome English scientist whom she had often seen working in the laboratory at odd hours. He appeared to be sleeping. His shirt was open and a strange apparatus was strapped to his chest. Rubber tubing stretched from this apparatus to a table filled with equipment next to him. A smoked paper drum rotated slowly. The needle of the drum was motionless, then suddenly jumped. Startled, she let out a little gasp. “Professor, Professor,” she called out. “Are you alright?” She noted he looked very pale, deathly so. She touched his hand. It was cold.

She ran to get help. The police took Professor George Mines to the hospital. There he briefly regained consciousness, but not long enough for him to explain what had happened. He died later that day. He was 29 years old. During his brief life, he used animal models to describe the physiology of reentry in the heart. He described the mechanism of supraventricular tachycardia in Wolff-Parkinson-White Syndrome long before that syndrome was described. He used a telegraph key to deliver timed electrical shocks to rabbit hearts, inducing ventricular fibrillation which he described without the benefit of an electrocardiogram. He thus was the first to report the existence of the ventricular vulnerable period. Despite all this amazing work, much of what he discovered was little noted at the time, until “rediscovered” by later researchers.

It seems likely that he was the first to induce arrhythmias in a human, long before the field of clinical cardiac electrophysiology. Unfortunately that human was himself, and the result was his own death.

The published papers of George Mines are fascinating to read. His very primitive equipment by today’s standards was more than compensated for by his remarkable ingenuity and keen powers of observation and reasoning.  He described the relationships between conduction velocity and refractoriness in reentry, the existence of an excitable gap, and deduced the reentrant nature of ventricular fibrillation. In one memorable experiment he cut fibrillating tissue into larger and larger loops until he was left with just one circulating wavefront. Amazing stuff! What more would he have accomplished had his life not been cut short?

Back in the days before the Internet, I used to keep photocopies of medical articles in a file cabinet (actually several large file cabinets). In those days of academia I enjoyed going to the stacks of the medical library and randomly reading articles from old bound journals, some dating back to the 19th century.  I learned a lot.  One thing I learned was that science has a problem with collective amnesia.  Discoveries are often forgotten or ignored, only to be rediscovered years later.

Nowadays everything is online. Or is it? Recently I wanted to look up Bazett’s original article on correcting the QT interval for heart rate. It was published in Heart in 1920 (Bazett HC. (1920). “An analysis of the time-relations of electrocardiograms”. Heart (7): 353–370.) These old volumes of Heart have not been digitized and are not online. Such a famous article though is surely reprinted? Indeed it is, on the Wiley Online Library site. I can get a copy of the PDF for $38. Absurd! An article from 1920 costs $38!

Here we see the bitrot of science, the impermanence of knowledge. On the one hand, modern scientific research is largely hidden behind a paywall, so that the poor (in the financial sense) reader must rely on abstracts, news reports, online sites such as Medscape, and presentations at medical meetings to keep up-to-date, instead of a careful reading of research methods and results. On the other hand, our precious scientific heritage, the published papers of previous generations, remains largely undigitized, residing in the dusty stacks of libraries, increasingly ignored by newer generations to whom nothing matters if it is not online. There are some exceptions. The Journal of Physiology has digitized all of its content back to Volume 1 from 1878. But most publishers haven’t bothered doing this.

At least half of early films have been lost. Early TV archives, like those of Dr. Who were routinely destroyed or copied over, resulting in loss of these shows forever. The situation is not so dire with old scientific research. The libraries will remain for a long time, and paper has a good half-life. But the beautiful work of George Mines and those like him, the true pioneers of medicine, will remain largely obscure to future generations unless that work is available online.

Perhaps some portion of the $38 for a PDF copy of a 1920 article could go to that cause.

EP Studios App Updates

Here’s what’s going on with the EP Studios apps:

EP Calipers

Most of the new stuff is in EP Calipers. Probably the most useful new feature is available on the Mac and Windows versions: a transparent floating caliper window. Use it to overlay calipers over any open window on the desktop. Check figures of journal articles. Use it during slide shows. Use it on webpages or on your EHR. No longer are you limited to just image files you have downloaded onto your computer. Unfortunately due to the nature of mobile device platforms, there is no way to implement similar functionality on a phone or tablet (that I know of).

Using the floating transparent window to check measurements in a published academic paper. It appears the pacing CL is actually 240, not 250 msec.

Several users suggested the capability to color each caliper differently. This is now implemented. Others wanted a way to fine tune caliper position besides just dragging with your finger or trackpad/mouse. This is also implemented, via keyboard arrow keys or buttons that “micromove” or “tweak” caliper positioning.

Finally, in case you missed it, angle calipers are available. They can be useful in Brugada syndrome, in which the so-called beta angle may have predictive value. In addition, the work of Dr. Adrian Baranchuk from Queen’s University in Kingston, Ontario indicates that there is prognostic value to measuring the base of the triangle formed by the angle 5 mm inferior to the beta angle triangle’s apex. EP Calipers now supports this. Provided amplitude has been calibrated in mm, the triangle base is automatically drawn showing this measurement. This technique has been dubbed by Dr. Baranchuk as a “Brugadometer.”  More information on these Brugada Syndrome ECG measurements can be found here.

Using the Brugadometer to measure the beta angle and the triangle base 5 mm below the apex.

EP Coding

EP Coding also received a major update earlier this year. After a few years of relative stasis, the AMA decided to shake up the coding of EP procedures once again by unbundling the sedation component from the procedure codes. The result is a relatively complex coding system for sedation, depending on factors of patient age, who does the sedation, and the sedation duration. EP Coding now allows you to calculate the sedation codes automatically using a sedation coding calculator.

Sedation coding calculator

 

EP Mobile

EP Mobile has been relatively static. It is already chock full of calculators, drug information, risk scores, pictures of ECGs, etc. It is our best selling app, so we must be doing something right. I am always happy to add features; just email me at mannd@epstudiossoftware.com with your requests.

Final thoughts

This is a bit off-topic, but probably not worth a separate blog post either. My old Motorola Droid Maxx Android phone is getting a bit long in the tooth, and way past upgrade time. I was an early adapter of Android, and though I use other Apple products (a Macbook Pro and an iPad Mini 2), I have never owned an iPhone. This may change. In many ways I think Android is a more innovative operating system than Apple’s iOS. Nevertheless we live in an insecure world, and I can’t get timely updates to Android via my phone and Verizon. My phone is stuck on Android 4.4.4 (I even forget what candy that is), whereas the most recent Android version is Android 7 Nougat.  Apple doesn’t have this problem.  Having an outdated, obsolete OS in the current world of bad guy hackers is untenable. I think the problem is (as usual) with the providers, who could care less about updating an older phone when they could be pushing the latest phones on customers. The 2 year cycle of upgrading phones is ridiculously wasteful. But that’s what is driving the industry, with the carriers all too eager to get you in and sign another rip-off contract. So, it might be goodbye to Android soon.

Thoughts on Mark Josephson

I’m sure there will be plenty of tributes to Dr. Josephson in the next few days from his colleagues who knew him well and those who didn’t know him personally but learned so much from his books and articles. I fall somewhere in the middle. I wasn’t one of his students at Penn who learned from him directly. I did meet him several times. I did work for years at the University of Colorado with Alden Harken, the surgeon with whom Dr. Josephson developed the “Pennsylvania Peel” — endocardial resection, the first surgical treatment for ventricular tachycardia. Oh, and I did live in the same apartment Mark used to live in during my cardiology fellowship in Philadelphia in the 1970s. More on that later.

Mark Josephson may represent somewhat of a dying breed in academia. In the great academic triad of clinical care, research, and teaching, the last element, teaching, which makes the least money for institutions, is emphasized less and less. Dr. Josephson excelled as a teacher. A lucky few were able to experience his teaching skills first-hand. A far greater number learned from his writing, in particular, from his opus magnum Clinical Cardiac Electrophysiology. Originally a relatively small but densely written book in a red binding, subsequent editions were more massive, filled with page after page of painstakingly labeled intracardiac recordings and clear-cut explanations of obscure electrophysiologic phenomena. I cut my teeth on this book, reading the original through when I was an EP fellow in Houston, and then reading the 2nd edition straight through when preparing for my first EP boards.

The book was important because it set a standard for analysis of intracardiac recordings that inspired subsequent researchers and students of the field. Back in the 70s and 80s, the mechanisms for most major arrhythmias (with the exception perhaps of atrial fibrillation) were worked out solely by analysis of intracardiac recordings and a few pacing techniques. Mark Josephson was instrumental in this process. Back then, working on arrhythmia mechanisms was the important thing. Therapies for ventricular tachycardia were drugs like quinidine or procainamide, and EP-guided drug therapy was, in retrospective, a pseudoscience. Yet working out the mechanisms of WPW syndrome, supraventricular tachycardia, and ventricular tachycardia eventually led to effective ablation and device therapy in the 1990s and beyond.

Dr. Josephson, who along with a cadre of first-generation EP superstars trained by Dr. Anthony Damato (the “godfather” of EP) at the Staten Island Public Health Hospital, set a standard for teaching in the field of electrophysiology that was often emulated, but never matched. Moreover he wrote a number of incisive editorials over the years in an attempt to keep the field rooted in its scientific basis, rather than be swept away by the insidious influence of industry or the idea that it wasn’t necessary to understand the pathophysiology of an arrhythmia if you were just going to burn it away.

As mentioned above, I was lucky enough to meet him on a few occasions and to round with him. By coincidence we discovered that the apartment on Henry Avenue in Philadelphia where I lived when I was a fellow was the exact same apartment he had lived in several years before. He remembered well the old guy who lived one floor above us, a fellow by the name of Sullivan, nicknamed “Sully.” I was just a plain cardiology fellow when I lived there, only subsequently deciding to go into EP and move to Houston for training. I always wondered if I picked up some kind of EP karma from living there. Who knows?

The advances in diagnosis and treatment of arrhythmias that have occurred since the 1970s are extraordinary, and uncounted numbers of people have benefited from these advances.  It seems a shame that most lay people, saddened at the loss of actors, musicians, sports heroes, and other celebrities, have no knowledge whatsoever of the passing of people who have actually had much more impact on their lives, like Dr. Josephson.  So it’s up to us, his colleagues, to remember Mark Josephson and give thanks for his incredible contributions to medicine and the world.

Massive Heart Attacks

Google Ngram of the phrase “massive heart attack”

Carrie Fisher’s sad, premature death is an occasion to reflect upon the poor job the news media does in reporting medical news. The initial report from TMZ had the headline “Carrie Fisher Massive Heart Attack on Plane.” If one equates “heart attack” to the more precise medical term “myocardial infarction,” as is usually done, then this is certainly diagnostic overreach on the part of TMZ. From their report it appears that Fisher suffered a cardiac arrest; indeed that term is used in the body of the article. So why not use that term in their headline? Perhaps massive heart attack sounds more dramatic. The word “massive” seems to go naturally with “heart attack.” Try to think of other phrases in which massive fits so well. Massive hack? Massive debt, perhaps? Few phrases roll off the tongue as well as “massive heart attack.” But most of the time when used by the media this phrase is not at all accurate.  Rather it is a catch-all term to indicate something serious related to the heart has occurred.

Of course we don’t know exactly what happened to Carrie Fisher, nor is it any of our business, but none of the information available indicates that she had a large myocardial infarction as opposed to a primary arrhythmic event like ventricular fibrillation or ventricular tachycardia. As a cardiologist having seen this sort of event a depressingly large number of times it is possible to speculate on what happened.  She likely suffered a cardiac arrest related to an abnormal heart rhythm starting suddenly in the heart’s ventricles.  Lay persons and the media often refer to this as the heart “stopping.”  While the pumping of the heart stops or is reduced, in actuality the heart is beating very fast or in a disorganized fashion to the point where it can’t effectively pump blood.   Without rapid correction using an electrical defibrillator this leads to sudden death.

In Carrie Fisher’s case CPR was administered while the plane was still in flight. It is unclear how much time elapsed between the onset of the cardiac arrest and administration of CPR.  It is difficult to tell from the reports if an AED was used on the plane or if defibrillation was attempted only after the plane landed.   We know she never regained consciousness and most likely suffered brain death due to prolonged interrupted circulation.

Carrie Fisher was a cigarette smoker and used cocaine, at least during her Star Wars days.  Could heart disease caused by smoking and drug use have contributed to her sudden death? Could more recent use of drugs like cocaine have been a factor? We don’t know, but if the family deems it fitting that the circumstances of her death be made public, it might help educate the public and the news media on some of the nuances of heart disease and the difference between a “massive heart attack” and a cardiac arrest.

Finally it is interesting to examine some of this lay cardiac terminology using Google Ngrams. The Google Ngram site is a search engine that can be used to look up the frequency of words or phrases in thousands of books published over many years. It can help establish when certain phrases like “heart attack” or “cardiac arrest” were first used and when they became popular. The Ngram at the top of this post of the phrase “massive heart attack” shows the rise in popularity of this phrase over the last 50 years. The Ngram below compares the terms “heart attack”, “myocardial infarction”, “sudden death”, and “cardiac arrest.” It is interesting that “sudden death” is a term that has been used without much change in frequency since the year 1800. “Myocardial infarction” and “cardiac arrest” both entered the literature around 1930-1940. “Heart attack” dates back to around 1920, but has become more and more popular, while the medical term, “myocardial infarction” seems to be less used recently. Curiously although the phrase “heart attack” has been around since the 1920s, it is only since 1960 that the phrase “massive heart attack” has become popular.  One wonders why.  These kinds of results are open to all kinds of interpretation: I’ll leave that to the reader as an exercise. But I encourage you to try Ngrams out yourself, on any subject that interests you. The results are often fascinating.

Google Ngram of other heart attack related phrases

EP Calipers for Windows

EP Calipers for Windows
EP Calipers for Windows

EP Calipers for Windows is done.  Whew.  As stated in my previous post, porting the app to Windows was a bit of a struggle.  Installing tools like a bash shell, git and Emacs took some time and effort.  The Windows tool to bridge iOS apps didn’t work.  So I was forced to port the code from objective C to C# and .NET by hand.  This took some time.

Looking back on my previous post with the benefit of hindsight, I think I was a bit too harsh on the Windows development environment.  I grew fond of C#, the .NET API, and the Visual Studio IDE as I got used to them.  Visual Studio is at least as good, if not better, than Xcode, Eclipse, or Android Studio.  Kudos to the Microsoft developers.

EP Calipers is a Windows forms app, meaning it runs on desktop, laptop, and tablet versions of Windows 10.  It is not a Universal Windows Platform (UWP) app.  With the market share of Windows phones dropping below 1%, and doubting that anyone would run EP Calipers on an X-box, I didn’t see any point in developing a UWP app.  I know most hospital desktops run Windows (though how many run Windows 10 now, I wonder?), and many docs have Windows laptops or tablets.  An app targeting the traditional Windows desktop seemed like the best approach.

One drawback is that the Windows Store only lists UWP apps.  It would be nice if they would also distribute desktop apps.  As such, I have to host the app myself.  You can download it from the EP Calipers page.

The program has all the features of the other versions of the app, including the ability to tweak the image rotation, zoom in and out, and load PDF files such as AliveCor™ ECGs.  .NET does not include a native PDF handling library.  In order to load PDF files in EP Calipers for Windows it is necessary to install the GhostScript library.  The free GPL version of the library can be used as EP Calipers uses the open source GNU GPL v3.0 license.  It is necessary to choose whether you are running the 32-bit or 64-bit version of Windows to download the correct version of Ghostscript.  Right-click on This PC and select Properties to see which version of Windows your computer is running.

As always please let me know if you have any problems or suggestions for the program, or for any of the EP Studios apps.  I nearly always incorporate users’ suggestions into these apps, and the apps have benefited greatly from this feedback.  Thanks to everyone who has shared their ideas and opinions with me!

What If My CHA2DS2-VASc Score Is One?

There is nothing simple about atrial fibrillation; it is a complicated, often overwhelming disease, both for patient and physician. One question that invariably comes up early on is the question of prophylactic anticoagulation for prevention of stroke. Who should receive anticoagulation? Which anticoagulant? How should anticoagulation be handled around the time of surgical procedures, or before and after ablation or cardioversion? How should anticoagulation be monitored? How should it be modified in patients with kidney or liver disease? Should anticoagulation be used in patients who have increased bleeding risks? Just the topic of anticoagulation in atrial fibrillation is overwhelming!  Too much for a short blog post. We’ll have to narrow this down further. Let’s talk about using risk scores to decide who should be placed on anticoagulation therapy.

chadsvascAtrial fibrillation risk scores were designed to assess stroke risk in patient populations with atrial fibrillation “without valvular heart disease.” I quoted that because “without valvular heart disease” is not well defined for this purpose. Certainly these risk scores don’t apply to patients with prosthetic heart valves, or with rheumatic mitral stenosis, but beyond that in practice these scores seem to be used even in patients with mild to moderate non-rheumatic valvular disease. The CHADS2 score is very simple, but has become passé in recent years. It is too gross a measure; people with low scores can still be at significant risk for stroke. It has been replaced by the CHA2DS2-VASc score in recently published guidelines. This score makes it much harder to achieve a score of 0 and escape anticoagulation. Using this risk score, both the 2012 European Society of Cardiology (ESC) and 2014 American Heart Association/American College of Cardiology/Heart Rhythm Society (AHA/ACC/HRS) atrial fibrillation guidelines recommend no anticoagulation if the score is zero, and full anticoagulation if it is 2 or greater. Where there is some hesitation, if not disagreement, is when the CHA2DS2-VASc score is 1.  Anticoagulate or not? The previous iteration of the guidelines leaned strongly toward anticoagulation for a CHA2DS2-VASc score of 1. The latest sets of guidelines are more equivocal. How to handle a score of 1 is particularly important when one realizes that female sex, on its own, is a risk factor in CHA2DS2-VASc with a point value of 1. Yes, half the people on the planet are born with a CHA2DS2-VASc score of 1 and by the old guidelines would require anticoagulation just on the basis of their sex.

A Swedish study published in 2012 sheds some light on this issue. The study concluded that, while female sex is a risk factor for stroke in atrial fibrillation if other risk factors are present, by itself, in women less than 65 years old without other risk factors, female sex does not confer a significant risk of stroke. The implication is that a CHA2DS2-VASc score of 1 that is only due to female sex does not warrant anticoagulation.

The results of this study were directly incorporated into the 2012 ESC guidelines (I note that Dr. Gregory Lip is a coauthor of both these guidelines and the Swedish study). Thus the recommendation by the ESC is full anticoagulation (aspirin and aspirin + clopidogrel are relegated to remote second-line therapy) for CHA2DS2-VASc score of 1 or higher, after excluding females with no other risk factors and age < 65 years, who (as with men with the same criteria) do not need anticoagulation.

The AHA/ACC/HRS 2014 atrial fibrillation guidelines are more vague than the ESC guidelines when the CHA2DS2-VASc score precisely equals 1. Cardiology guidelines are presented using a sort of quantified equivocation, with recommendations classified as I (should do it), IIa (reasonable to do it), IIb (you can consider doing it) or III (don’t do it). Not quite orthogonal, there are 3 levels of certainty as well: A (data derived from multiple randomized clinical trials), B (data from one randomized clinical trial), or C (“expert” opinion). Given this, it is interesting that anticoagulation for a CHA2DS2-VASc score of 2 or more is a class I, A level of evidence recommendation, and no anticoagulation for a score of 0 is a class IIa, B level of evidence recommendation. For a CHA2DS2-VASc score of 1 there is complete equivocation, with the following class IIb recommendation:

For patients with nonvalvular AF and a CHA2DS2-VASc score of 1, no antithrombotic therapy or treatment with an oral anticoagulant or aspirin may be considered. (Level of Evidence: C)

Addressing the possibility of a exclusion for females with a CHA2DS2-VASc score of 1, the guidelines state (again equivocating):

"In a study of Swedish patients with nonvalvular AF, women again had a moderately increased stroke risk compared with men; however, women younger than 65 years of age and without other AF risk factors had a low risk for stroke, and it was concluded that anticoagulant treatment was not required. However, the continued evolution of AF-related thromboembolic risk evaluation is needed."

This all creates a problem for physicians, patients (females especially), and also for the physician-programmer writing an app such as EP Mobile that calculates these risk scores and attempts to make recommendations. At present EP Mobile simply uses the old recommendations, as do most of the web-based online risk score calculators I surveyed (e.g. here and here). A user of EP Mobile pointed out to me that its recommendations are out of date.  Trying to fit such complexity into a small dialog box on a smartphone screen is challenging.  Nevertheless I will be updating the app so that its anticoagulation recommendations more precisely match current guidelines — at least until the next set of guidelines comes out.

Introducing EP Calipers

epcalipersicon-180x180Ever since the 1990s, when computer-based electrophysiology (EP) systems were introduced, HV intervals and ventricular tachycardia cycle lengths have been measured in the EP lab by electronic calipers — simple but accurate measurements accomplished on-screen using a track ball or a mouse. Despite this, physicians still often carry a physical pair of calipers, perhaps preserved from the pre-Sunshine Act days when they were provided for free by drug companies. They use these calipers to measure heart rates and QT intervals on printed electrocardiograms (ECGs). But more and more, ECGs are viewed electronically. All physicians now use smart phones and frequently send and receive photos of ECGs or rhythm strips for analysis. For example, when I was on-call there would often be a patient who went into atrial fibrillation in the middle of the night, or a patient who would be due a dose of dofetilide (a potentially dangerous QT interval prolonging drug). The nurse would have a rhythm strip or ECG that needed analyzing and the easiest way to do that in the post-fax machine era was for them to take a photo with a smart phone and text or email it to me for analysis. Measuring heart rates or corrected QT intervals requires the use of calipers, but physical calipers don’t work well with smart phones — maybe even scratching the glass screen! Electronic calipers akin to those used in the EP lab would be useful to make accurate measurements on ECG and rhythm strip images.

I did not realize that there weren’t any apps (as far as I can tell) providing electronic calipers until this was pointed out to me by one of my Twitter buddies, Dr. Michael Katz. So I wrote an app, EP Calipers, that provides these calipers.

Making EP measurements on an iPad
Making EP measurements on an iPad
Measuring RR interval, iPhone 6 Plus
Measuring RR interval, iPhone 6 Plus
Amplitude measurement
Amplitude measurement
QT measurement with QTc calculation
QT measurement with QTc calculation
Multiple calipers, showing heart rate
Multiple calipers, showing heart rate

As the screen shots show, these calipers look just like those provided by EP recording systems, such as the GE (formerly Prucka) Cardiolab system. Multiple calipers can be used at the same time. Both time and amplitude calipers are available.  Unlike real calipers, it is possible to zoom images and make much more accurate measurements. Also unlike real calipers, it is easy to measure mean heart rates and calculate QTc intervals automatically.  The app makes the necessary calculations.

I am hoping these electronic calipers will be easy to use and helpful to anyone who has to deal with ECG recordings. This is the first iteration of the app and I am open to suggestions to improve it. Right now the app is available for Apple iOS (version 8.1 or higher required), but the Android version will be available Real Soon Now. Have fun measuring intervals electronically to your heart’s content!

EP Mobile Update Version 3.6 for Apple Devices

The reviewers at the Apple iTunes App Store have approved the revised version of the EP Mobile app.  For information on why the app needed to be revised, see my earlier posts on the subject.  I removed the drug dose calculators (note though that the Warfarin Clinic module was not removed), but added detailed drug dosing information and a creatinine clearance calculator that can be used while viewing the dosing information.  Other improvements to the app have been made as well.  The changelog is as follows:

Changes from version 3.5
* Removed drug dose calculators as requested by Apple (see developers guide section 22.9)
* Added new drug reference section with creatinine clearance toolbar
* Added creatinine clearance calculator
* Added right ventricular hypertrophy criteria
* Added D'Avila WPW accessory pathway location algorithm

I will release the new version in 2 days (March 22).  If for some reason you can’t live without the drug dose calculators, then don’t update the app.  Turn autoupdate off if it is on to prevent inadvertently updating the app.  Regardless of the lack of drug dose calculators, I encourage most people to update the app, because I think that using the new drug reference information in the app is a better way to determine drug dosages, and because I will continue to add new features to the app, which will not be available to those who do not update.

Note that Android users of EP Mobile still have access to the drug dose calculators, as well as the new features noted above.

I hope that at some point Apple changes its policy and adds physicians to the groups permitted to write apps that calculate drug doses.  After all, it’s what we do.

Countdown to version 3.6 release — Done! Released Mar 22, 2015!

[wpc_countdown theme=”flat-colors” now=”1426860240465″ end=”48″ bg=”#fff” padding=”5″]

 

Update on EP Mobile and Apple #2

As some of you are aware, the Apple App Store rejected an update to the EP Mobile app based on the presence of drug dose calculators in the app. The App Store guidelines state:

22.9 - Apps that calculate medicinal dosages must be submitted by the manufacturer of those medications or recognized institutions such as hospitals, insurance companies, and universities

For those who want more background on this issue, see these two previous posts (here and here).

I have decided to go ahead and remove the drug calculators from the app. All the drug calculator code remains in the app and, should Apple ever change their mind(s) on this policy, it will only require changing this single line of code to get them back.

// Sigh!
#define ALLOW_DRUG_CALCULATORS NO

I toyed with putting a backdoor into the app to activate the drug calculators, but I realize if I do something like that it would be my last Apple app. I have modified the app to make up for the loss of the drug calculators, and I think that with these changes you will continue to be satisfied by the app.

Here are the changes.

The creatinine clearance calculator had been embedded in the drug calculators, so it has been promoted to its own discrete module (which is something I should have done anyway a long time ago.

EP Mobile Main Menu Drug calculators gone, creatinine clearance calculator added
EP Mobile Main Menu
drug calculators gone, creatinine clearance calculator added

Instead of the drug calculators, there is a drug reference section. Each of the drugs that formerly had calculators now has detailed dosing information, as well as other useful information, akin to what you find in the Medscape app. (An aside: I think drug dosage information as opposed to drug dose calculators is acceptable to Apple, as it is present in Medscape and other medical apps. Medscape does not meet the Apple criteria mentioned above any more than EP Studios does: it is not “the manufacturer of those medications or [a] recognized institution […] such as hospitals, insurance companies, and universities.”).

Two new modules: Right Ventricular Hypertrophy and Drug Reference
Two new modules: Right Ventricular Hypertrophy and Drug Reference

What makes the drug reference section more useful than the similar information in Medscape is that there is a toolbar at the bottom of the screen that allows you to calculate a creatinine clearance on the fly, and then retains that information while you are trying to figure out the appropriate drug dose. Thus the only calculation done is the creatinine clearance; the physician and not the app decides of the dose. In many ways this is superior than having a drug dose calculator, because more information is presented that may be useful to help decide on the proper dose.  The drug reference section can also be expanded in the future to include information on other EP related drugs that don’t necessary require any calculations to dose, such as amiodarone or ibutilide.

A portion of the drug reference for dofetilide. Note the detailed dosing information and the Creatinine Clearance toolbar at the bottom showing the last calculated CrCl.

 

Finally the D’Avila WPW algorithm has been added, as well as a module on diagnosing right ventricular hypertrophy. I have left in the Warfarin Clinic module too. This module was not called out by Apple on the last review, so we shall leave it alone for now.

I will submit the update to Apple in the next 24 hours. Their review process usually takes about a week. If the approve it, I will not release the update right away, but will give some advance notice on Twitter. If you really can’t live without the drug calculators, then you should turn off auto-update and not update the app. I think though that the drug reference section with the built-in creatinine clearance calculator more than makes up for the loss of the drug calculators, and I encourage you to update the app when it is available.

If you happen to be best buds with Tim Cook, let him know that rule 22.9 is stupid and should be sacked.

Update on EP Mobile and Apple

This is an update on my previous post which dealt with Apple’s rejection of an update to the EP Mobile app because it contained drug dose calculators. According to a clause buried in the App Store Review Guidelines (section 22.9, to be precise),

22.9 apps that calculate medicinal dosages must be submitted by the manufacturer of those medications or recognized institutions such as hospitals, insurance companies, and universities.

EP Mobile has included such dosage calculators from its very first version, but for some reason the current update (which just added the D’Avila algorithm [PACE 1995;8:1615-1627] for determining accessory pathway location) triggered the discovery that the app was in violation of this rule. I was unaware of this rule, and I don’t think the rule was extant when I submitted the first iOS version of the app in 2012.

I submitted an appeal to Apple stating that as physicians have to calculate drug doses every day there does not seem to be any reason a physician-programmer should not be permitted to write an app to calculate drug doses. A drug company could only produce an app for their specific drug, so they could not duplicate the functionality of having multiple drugs from different companies in one app. I don’t see any incentive for a hospital, insurance company, or university to develop this kind of app, though I suppose it is possible they could. As a physician I developed the app because it was useful in my daily work. It makes figuring out drug doses for certain anti-arrhythmic drugs or anticoagulants much easier. As far as I know that specific functionality is not duplicated in the App Store.

Apixaban Dose Calculator
Apixaban Dose Calculator

Apple stuck to their guns and maintained the app update could not be approved. On Twitter a colleague tweeted this article from iMedicalApps of June 2013 which discusses the problems that Apple has with drug dosage apps. Apple is probably concerned about the FDA’s potential scrutiny of medical apps and possible legal liability for drug dose calculators that could give erroneous information. In any case this article points out that the Medscape app also provides drug dosing information (though only as written information, not as a calculator — I’m not certain, but it appears that the App Store Review Guidelines may have changed from banning dosing information altogether to just banning dose calculators). Medscape is owned by a private company (WebMD) and is neither drug company, hospital, insurance company nor university.

Medscape iPhone app provides drug dose information
Medscape iPhone app provides drug dose information

If the Medscape model for presenting drug dose information is legitimate in Apple’s eyes (as opposed to a violation that just hasn’t been noticed yet), it would be possible to retool my app to provide a creatinine clearance calculator followed by the specific dosing information for each drug. This is not as slick as having the answer just pop up in a dialog box, but on the other hand does show exactly what the dosing criteria are and removes the computer from the decision making process. However if I go that route there is no way to save one of my favorite parts of the app, the warfarin dose calculator. It is an implementation of an algorithm from this paper and provides suggested dosing changes for patients on chronic warfarin based on their INR, INR target, weekly total dose, and tablet size. It suggests how many pills the patient should take each day of the week. Whoever makes generic warfarin is not likely to develop a warfarin dose calculator like this, nor is anyone else.

iOS Simulator Screen Shot Feb 20, 2015, 7.50.40 PMiOS Simulator Screen Shot Feb 20, 2015, 7.50.23 PM

At this point I have requested further information from Apple. Apple has rejected the update to EP Mobile, but they have not requested I withdraw the current version of the program (which still has all the drug calculators in it). Certainly they might do so. In the hopes that their position will change, I have decided to withdraw the update and leave the app as is, unless Apple tells me otherwise. This is not a good long term strategy as I like to update the app frequently to keep it up to date with what is going on in electrophysiology, and I am now blocked from making any updates that don’t remove the drug calculator functionality. If I do release an update that does not contain the drug calculators, I will announce it well ahead of time on Twitter and on this site to give users the option not to update the app. I should also point out that the Android version of the app has not been challenged (Android is very hands off compared with Apple).

I am hoping that Apple will consider this further, based on this section of their App Store Review Guidelines:

This is a living document, and new Apps presenting new questions may result in new rules at any time. Perhaps your App will trigger this.