Since its debut last year, the iPhone ECG has proven its worth by diagnosing previously asymptomatic patients and college athletes.

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An initial study of the iPhone ECG -- which we've covered since its popular YouTube video was released last year -- was presented at this past week's American College of Cardiology 61st Annual Scientific Sessions in Chicago. The highly anticipated device is pending Food and Drug Administration (FDA) approval, though questions have abounded about how exactly it will be applied. For example, will it predominantly be used by patients, emergency responders, and/or clinicians, and what diagnostically useful information can be obtained from it?

Entitled "iPhone Rhythm Strip: Clinical Implications of Wireless and Ubiquitous Heart Rate Monitoring," the new eight-week study enrolled 54 participants and has begun to answer these and many other questions. According to the company:

After using the device, 24 percent of subjects reached out to their private physicians for a consultation and 16 percent felt that they discovered a health condition previously unknown to them. Seventy-five percent of participants requested continuation of the device usage after the eight-week study period. Thirty-three percent felt that they were more health conscious after participating in the study and 88 percent thought that the device was transmitting accurate information. Participants indicated that they found the portability, ease of use, and the form factor to be key aspects of the device that were most conducive for use.

"The study provided us with important information required to optimize the device for physician and patient application," commented Dr. [Leslie] Saxon. "This device incorporated into smartphones and tablets provides physicians and their patients with a clinical-quality, low-cost heart monitor that will increase the global availability of advanced cardiac monitoring."

We reached out again to the device's inventor, Dr. David Albert, and he provided the following anecdotes of how the iPhone ECG has been used:

alivecor-image.jpg We have diagnosed ventricular tachycardia in a previously asymptomatic 35-year-old man. We have diagnosed a new case of Wolff-Parkinson-White syndrome in a 41-year-old man, who is now being ablated. We have diagnosed paroxysmal supraventricular tachycardia in a 20-year-old college athlete who had been blown off by her coaches. We have diagnosed Atrioventricular Nodal Reentry Tachycardia in a 17-year-old congenital heart patient who was not diagnosed after a two-week Holter study. And we have diagnosed silent ischemia. Dr. Eric Topol has diagnosed an acute ST Elevation myocardial infarction on a plane, forcing it to land.

Now you must understand that we have not used our device in more than a couple of hundred people so this diagnostic yield is incredible.

Dr. Albert also sent us the abstract of the study, which we've included below:

Poster 1247-575

iPhone Rhythm Strip -- the Implications of Wireless and Ubiquitous Heart Rate Monitoring

Leslie A. Saxon, Alexandra Smith, Sona Doshi, Jessica Dinsdale, Dave Albert, University of Southern California, LOS ANGELES, CA, USA

Background: Wireless technologies enable transmission of high quality ECG recordings without the need for leads. A device incorporating electrodes into an Apple iPhone case allows for wireless recording of 30-second rhythm strips (LEAD 1) to the cloud (AliveCor, Okla. City, OK). ECGs can be downloaded for immediate interpretation using any browser.

Methods: iPhone-owning attendees of a Body Computing Conference at USC participated in an eight-week study to determine how they utilize the device.

Results: A total of 54 participants (43+/- 11 yrs, 77 percent male, 15 percent physicians, 61 percent business, 13 percent media/entertainment, 11 percent engineers) transmitted 36+/-53 30-second recordings weekly (range 3-298) for eight weeks. Without training, subjects used the case to record ECG's on themselves and others (61 percent). Transmission interpretation was normal sinus rhythm (68 percent); sinus brady or tachy (16 percent), extra atrial or ventricular systoles (two percent), QRS delay (one percent); and noise (13 percent). Symptomatic ventricular tachycardia and asymptomatic ST segment depression were detected in two participants, the latter in Mumbai, India.

Conclusion: Anytime ECG monitoring, as an adjunct to a smartphone is intuitive and allows users to learn about and characterize their heart rates and rhythms. It provides global identification of arryhythmias at any time. The implications of this technology for improving public awareness of health metrics and for the early diagnosis of arryhthmias are enormous.

This post also appears on medGadget, an Atlantic partner site.

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