A new clinical trial on the portable ECG (electrocardiogram) device AliveCor has been published. According to mobihealthnews, a study that aims to determine whether an ‘iphone ECG’ is capable of detecting heart attacks (specifically STEMI, which is a type of heart attack) with the same efficacy as the 12-lead ECG normally used in hospitals has been registered on clinicaltrials.gov, a website for listing clinical trials. The sponsoring institution for this study is Intermountain Health Care.
Clinicaltrials.gov is a website operated by the NIH where clinical trials are registered before they are started. The reason for this inconvenient process is to prevent ‘take and run’. In the case where clinical trials are conducted through the support of corporations like pharmaceutical companies, if the results are negative, it is likely that they will not be published. By registering clinical trials before they are conducted, one is able to keep track of the ongoing research, even if the results are not published in journals. Also, when the results are not so positive, it is possible that one might alter primary or secondary outcomes after the clinical study is terminated in order to produce positive results, and the website aims to prevent this.
It is stipulated in the Helsinki Declaration of 2008 that “Every research study involving human subjects must be registered in a publicly accessible database before recruitment of the first subject.” The International Committee of Medical Journal Editors has made it mandatory to register trials in the clinical trial registration system in order for researchers to publish studies in member journals. As a result, many countries have created clinical trial registration systems and these are often synchronized to the American website, clinicaltrials.gov. Thus, it can be said that clinicaltrials.gov is the most comprehensive clinical trial registration site in the world.
It is not clear whether the iphone ECG is AliveCor, but last year, Intermountain Health Care and AliveCor conducted a similar clinical study with 6 patients. The purpose of this study was ‘gaining experience with smartphone ECGs prior to conducting multi-institutional clinical trials comparing the smartphone ECG with the 12-lead ECG’, and one might guess that the current study is an extension of this previous study. The previous study was published, and since there is one more study prior to it, I will call this study “early study 2”.
I was very surprised to hear about the early study 2 and the study that is beginning now. This is because the original ECG shows 12 images, while AliveCor only shows a single image. Thus, the latter is not appropriate for detecting cardiac diseases other than abnormal heart rhythms (=arrhythmia) like atrial fibrillation.
To explain further, when taking a normal ECG, a total of 10 electrodes are placed: one on each hand and foot, and 6 on the chest. 12 images are obtained as a result, and each image corresponds to certain parts of the heart. As a result, if there is an abnormality at a specific part of the heart, it can be detected on one of the 12 images that corresponds to that part. (For instance, if a cardiac infarct occurs at the lower portion of the heart, an abnormality can be detected in the image that corresponds to leads II, III and aVF.) This is why it may be difficult to detect diseases that affects specific parts of the heart, like heart attacks, with a device that is only capable of acquiring a single image like AliveCor. Even the preexisting ECG only shows the anterior, base and lateral side of the heart, and does not detect well the abnormalities that occur in the back of the heart. (In this case, one must place 3 additional electrodes on the back to detect the infarct.)
If one is lucky and the myocardial infarct occurs in the front part of the heart and thus is detectable with AliveCor, or a medical personnel appropriately changes the location of the device, a diagnosis may be possible. An example of this would be when Dr. Eric Topol, the guru of digital healthcare, once saved a patient by diagnosing a heart attack (normally, this means myocardial infarct) with AliveCor on a plane.
However, the limit to using only a single lead is evident, and the original clinical studies on AliveCor focus on detecting abnormalities in cardiac rhythm like atrial fibrillation. For your reference, the portable ECG devices that can acquire up to 12 images are available in the market.
With this is mind, I was surprised to discover that the clinical studies from last year and this year (pilot studies to be more accurate) target the ECG’s of patients diagnosed not with arrhythmia but with myocardial infarct, and compare those obtained with AliveCor with those obtained with 12-lead ECG’s. ’What sort of trick is this,’ I thought.
There is not much information on the new clinical trial that is registered on clinicaltrials.gov, so I searched publications from last year. I discovered that there was one more study prior to the study mentioned above. I will call this ‘early study 1’. Regrettably, both articles are available to readers for a fee. The abstract is free, but does not contain detailed information. For those who are unwilling to pay but would like access to more detailed content, I recommend reading an article from Fierce medical device.
The title of early study 1 is ‘Surface 12 lead electrocardiogram recordings using smart phone technology). In the study, 12 ECG’s were taken of 5 subjects who were either normal or had cardiac abnormalities (LVH, LBBB, RBB) using AliveCor. These were compared to the results obtained with the standard 12-lead ECG.
The title of early study 2 is ‘Smart ECG for evaluation of STEMI: Results of the ST LEUIS Pilot Study’. In the paper, 6 STEMI patients were evaluated with the standard 12-lead ECG as well as AliveCor, and the results from the standard ECG were compared to those from the 12 different images taken with AliveCor.
Obviously, the key was how to obtain the 12 images with AliveCor. Early studies 1 and 2 both seem to have used the same method. The secret is contained in the figure published in early study 2.
AliveCor was not used exactly as it was sold, but was modified. In this manner, the leads were attached to different positions on the limbs and the chest, and after 12 times, 12 images were acquired.
Specifically how the images were obtained can be understood by looking at the picture in early study 1.
I am not familiar with the precise mechanism of electrocardiograms even though I am a board-certified physician. However, it is important to point out that although the method of obtaining aVR, aVL and aVF is different from that which applies to standard ECG’s, the images obtained through the novel method proved to be quite sufficient, to say the least.
In what sort of situation would using AliveCor to obtain 12 different ECG’s be efficient? This may be useful in nearly every situation where it might be difficult to use standard ECG’s. The authors of the paper point out in particular that this will be useful in rural areas that lack healthcare facilities, in developing countries and on cruise ships and buses.
It may be possible for the average person to utilize this at home, but realistically, it does not seem likely that a layman without proper education will be able to correctly take 12 images one at a time. In this case, one may consider having educated personnel use the device in certain areas (such as in health centers in rural areas).
If the device is hard to use, what if one was instructed on how to take ECG’s in real time using the video function on smartphones? This is of course possible but one must take into account that ECG’s do not provide a complete solution for diagnosing cardiac diseases. To repeat a story from my book, imagine a situation where there is chest pain that suggests myocardial infarct:
- Even when there is no abnormality on the ECG, one cannot rule out the possibility of a myocardial infarct
- Although chest pain in a patient may be suggestive of myocardial infarct, it may be due to conditions like aortic dissection or pulmonary embolism that are no less dangerous than the myocardial infarct and are difficult to diagnose via ECG. Therefore, in the case of severe chest pain, if it is not impossible to go to a hospital, the best thing to do would be to race to the hospital, rather than try to obtain 12 images using AliveCor.
AliveCor’s recent research efforts to obtain 12 images like the standard ECG seem to be in order to overcome the limit that acquiring only a single image places on the original product, which can only be used to diagnose cardiac arrhythmia. It is likely that AliveCor may already be developing a product that operates on the same principle as the device shown in the first image, but looks better and is more convenient to use. If so, the target market will be rural areas that are distant from hospitals or developing countries, However, in these cases, especially in developing countries, funding for healthcare will be limited and will need to be distributed efficiently. Practically speaking, cardiac diseases (especially diseases like myocardial infarct) are secondary in importance to infectious diseases, and purchasing AliveCor may not be the most cost-efficient decision. Whatever the case, as I have presented in an earlier post, AliveCor is presumed to have sold fewer devices than expected, and this may be an opportunity to overcome this problem.