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| COMMENTARY |
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| Year : 2017 | Volume
: 3
| Issue : 3 | Page : 120-122 |
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Personalized medicine: Digital electrocardiography
David P Skinner1, Hersh V Goel1, Joseph S Alpert2
1 Southern Arizona Urgent Care, LLC, Tucson, Arizona, USA
2 Department of Medicine, University of Arizona College of Medicine, Tucson, Arizona, USA
| Date of Web Publication | 7-Dec-2017 |
Correspondence Address:
Joseph S Alpert
Department of Medicine, University of Arizona College of Medicine, 1501 North Campbell Avenue, Tucson, Arizona 85724
USA
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/digm.digm_38_17
How to cite this article:
Skinner DP, Goel HV, Alpert JS. Personalized medicine: Digital electrocardiography. Digit Med 2017;3:120-2 |
Ambulatory electrocardiographic monitoring was first introduced in the 1960's by Norman J. Holter, who gave rise to the eponymous Holter Monitor.[1] More than 50 years have passed since the introduction of this breakthrough device and advances in technology has led to a large armamentarium of real-time electrocardiography (ECG) monitors. Transtelephonic event monitors record ECG tracings on command, and a variety of implantable devices can continuously record heart rate and rhythm over a substantial period, even months to years.[2],[3],[4],[5] The recent rise of mobile computing technology, however, is now resulting in a new phase of innovation in remote cardiac monitoring. Current day devices are wholly digital and work in conjunction with smartphones and the cloud to enable capabilities that extend far beyond real-time ECG monitoring. This new generation of mobile ECG devices allow physicians to perform real-time diagnosis and in some cases even real-time management and treatment.[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13] These sophisticated devices can apply algorithms to detect normal versus abnormal ECG recordings and will only get better with the burgeoning development of neural networks.
Despite the paradigm-shifting potential of these devices, the standard of care for patients with “fluttering” in their chests, known as palpitations, still remains unchanged. These patients are often referred to a cardiologist who will perform 24–72 h Holter monitoring to ascertain any potential underlying heart rhythm disturbance. If no arrhythmia is detected, a longer-term monitoring device such as a transtelephonic event monitor, is often employed. These evaluations are time-consuming and expensive and will remain at the forefront of detecting arrhythmias until the efficacy of mobile ECG devices is thoroughly investigated.
Our group has been particularly interested in studying the Kardia Mobile (KM) ECG Recorder (AliveCor, Mountain View, California), a first-of-its-kind device that was cleared by the FDA in 2014 for the detection of atrial fibrillation (AF). This KM technology requires a “smart” mobile device to connect to and consists of portable single-lead ECG sensors, and a mobile software application that enables ECG tracings to be recorded, saved and transmitted securely over the internet. In the United States, the KM instrument currently sells for approximately $100 and can easily be carried in a pocket, purse, or affixed directly to the back of a smartphone. On the onset of palpitations, patients have the capacity to instantly record accurate and readable 30 s rhythm strips that are automatically sent to their physician through the KM Pro application, which was newly released in the spring of 2017.
A number of early studies using the KM device to detect arrhythmias in a variety of patient populations are steadily entering the peer-review literature. One of the first was the study of Lowres et al. in Sydney, Australia.[6] These investigators placed this device in a pharmacy and recorded rhythm strips from 1000 individuals age 65 or above. They detected previously undiagnosed AF in 1.5% of this population as well as an overall incidence of AF of 6.7%. Le Page et al. in the United Kingdom enrolled nearly 1000 individuals who attended a 3-day free heart screening event.[8] This group identified a variety of arrhythmias in this unselected population including AF, atrial flutter, atrial and ventricular premature beats (APBs or VPBs), bundle branch blocks, and even marked ST-segment depression in some individuals. Evans et al. used the KM device in Kenya, a limited health-care-resource setting.[7] They employed the device in five internet-connected hospitals and identified AF for the very first time in 8% of fifty patients. Hickey et al. are currently performing a single center, randomized, and controlled trial of the device for monitoring the frequency of recurrent AF in a population of 300 patients with a recent history of paroxysmal AF.[10] Patients will be randomized with half of the subjects receiving the KM device and half receiving usual care. In turn, the study authors hypothesize that more episodes of AF will be detected and treated in the group using KM devices compared with the control group.
The Southern Arizona Urgent Care-University of Arizona College of Medicine collaboration was initiated to further explore the efficacy of mobile ECG devices and simplify the evaluation process for patients with palpitations. Uniquely, this study will investigate the KM device's efficacy in the urgent care population, a hereto now little-studied population that is growing demonstrably nationwide. The question at the core of this study is whether the evaluation and management of patients with heart palpitations can be successfully diagnosed with the KM device and without the need for prolonged and expensive noninvasive or invasive ECG monitoring.
The protocol is as follows – one hundred patients who present with palpitations to one of five Urgent Care Centers of the Southern Arizona Urgent Care system will be offered the opportunity to participate in this study comparing Holter monitoring with KM's arrhythmia detection. In addition to a comparative analysis of accuracy in detection, cost-effectiveness of the new mobile technology will be assessed and compared with the same variable for Holter monitoring.
Patients 18 years of age or older who present with the appropriate symptoms, possess a smartphone, and provide informed consent to participate in the study will be furnished with a KM device. These individuals will be trained in the use of this instrument, thereby enabling them to record and transmit ECG rhythm strips when they detect an abnormality in their heart rhythm. Each of these individuals will also undergo a 24 h Holter monitoring session. The collected data from both devices will be analyzed by an experienced ambulatory ECG monitoring technician who is an employee of the University of Arizona as well as by Doctors HVG and JSA. Patients will be provided with the results of their studies, and they will be referred to a cardiologist for a final decision concerning any indicated standard of care management. Patients with a history of potentially life-threatening arrhythmias, for example, ventricular tachycardia, will be excluded from the trial.
The trial is underway at this time, and >20% of the patient population has already been enrolled. It is anticipated that the full complement of patients will be recruited within the next 6 months. Since this is an open-label trial, the early results are already known to Doctors HVG and JSA. What has been observed is as follows:
- Patients with very infrequent (fewer than 30 abnormal beats per 24 h) APBs or VPBs during the Holter monitor recording infrequently show any abnormal beats on their KM recordings. This is presumably because the extrasystole was isolated and did not recur during their KM rhythm strip. There is of course a delay between the onset of symptoms and the ability to obtain a recording with the smartphone application
- Patients with more frequent APBs and/or PVBs usually demonstrate the same arrhythmia during self-recorded rhythm sampling with the KM device
- Multiple extra beats such as coupled APBs or VPBs during Holter monitoring are usually also identified in rhythm strips recorded with the KM device. These can be missed if they are rare on the Holter monitor, for example, only once or twice in 24 h and of short duration, for example, three to four beats. Patients often have symptoms resulting from these multiple abnormal beats, however, as in the first observation, the KM recording is taken too late to record them.
At this time, the data are too preliminary to conclude whether or not the KM recordings are cost effective or not. However, one of the authors (JSA) has purchased this device and has used it on a number of patients and has recommended it to other patients who are having frequent palpitations. Two illustrative case reports that were observed during the last 3 months follow.
Case report # 1 – A 47-year-old Caucasian man was admitted to the hospital with left and right ventricular heart failure. He was in AF at a heart rate of 150–160 beats/min and was unaware of his rapid heart action. He underwent successful elective cardioversion and was discharged with metoprolol 50 mg BID. His symptoms of the left ventricular failure resolved. A week later while attending a social event, he reported to JSA that he had felt “unwell” that morning. Using JSA's KM device, a rhythm strip was recorded immediately that demonstrated that the patient was in AF with a heart rate of 130–140 beats/min. The patient was subsequently readmitted to hospital, and elective cardioversion and arrhythmia ablation were performed with complete and permanent resolution of AF and the heart failure syndrome. The patient purchased a KM device and periodically monitors his heart rate and rhythm.
Case report # 2 – A 55-year-old Caucasian man noted the gradual onset of increasing fatigue and dyspnea on exertion. He visited a local cardiologist who diagnosed atrial flutter at a heart rate of 150 beats/min (2:1 AV block). An echocardiogram demonstrated the left ventricular ejection fraction (LVEF) of 40%. The patient underwent elective cardioversion and was placed on carvedilol 25 mg BID and dronedarone 400 mg BID. The patient improved and several months later, the LVEF was found to be normal at 55%. One year later, the patient reported several weeks of unusual fatigue. His heart rate measured by a nurse acquaintance was 60 beats/min, however, a KM recording demonstrated atrial flutter with 4:1 AV block. The patient underwent successful cardioversion and arrhythmia ablation and has been asymptomatic and in sinus rhythm since the performance of these procedures. This patient has also purchased a KM device and periodically monitors his heart rate and rhythm.
Both of these patients demonstrate the utility of the KM device in patients with symptomatic and asymptomatic arrhythmias. In several other patients followed by JSA, the use of this device has empowered them and markedly decreased the anxiety surrounding their arrhythmias and heart conditions.
The portable, KM ECG device is an inexpensive digital technology that will undoubtedly find a place in daily clinical practice alongside a plethora of digital devices currently undergoing evaluation. Instruments such as the KM ECG recorder are excellent examples of the new trend toward personalized medicine and will clearly become a widely employed component in the further development of this growing field.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Conflict of interest
None declared.
| References | |  |
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