KardiaBand: a Single-Lead EKG for Apple Watch

choi

(1) On Nov 16, 2017 Food and Drug Administration (FDA) approved commercial sale to the public of Kardia Band )or KardiaBand), made by AliceCor based on Mountain View, Calif.
https://www.accessdata.fda.gov/cdrh_docs/pdf17/K171816.pdf
("We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the
enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance
with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device")
(2) KardiaBand is the first of this sort (to be explained later), so FDA could not compare it with its recently (after 1976, that is) approved model of other manufacturers. Company website describes "How It Works."
https://www.alivecor.com/
(a video clip)
(a) FAQs. AliveCor, undated
https://www.alivecor.com/faq/

Q: "Do I need phone service or Wi-Fi to take an EKG recording on my KardiaMobile?

A: "Once logged in, the Mobile EKG does not require a Wi-Fi or mobile connection to record an EKG and save it to the phone/tablet, however it requires one of these to sync automatically with the AliveCor server, email, or print directly from the Kardia app. If you do not have a Wi-Fi or mobile connection at the time of the EKG recording, you can email or print the data later when you have such a connection and the sync will happen automatically at that time.

(b) User Manual for Kardia™ by AliveCor®, dated Dec 12, 2017.
https://www.alivecor.com/user-manuals/00LB17.7-en.pdf
("Kardia™ by AliveCor® is a smartphone and smartwatch application that supports AliveCor's family of mobile, clinical-quality electrocardiogram (EKG or ECG) recorders. Users may use Kardia to record and display EKGs using Kardia Mobile with their smartphone or tablet, or the KardiaBand with their Apple Watch. The Kardia application also provides instant analysis of the recorded EKG to evaluate whether the heart rhythm is normal or if atrial fibrillation is detected.  The default duration of the recording is 30 seconds. * * * All Kardia devices have been favorably compared to Lead I recordings of a standard FDA-cleared 12-lead device. * * * Rest two or more fingers (it doesn’t matter which fingers) on Kardia Mobile, with your right hand on one electrode and your left hand on the other. Recording of a Lead I EKG on the Kardia phone app will begin automatically when you make good contact with the Kardia Mobile electrodes")
(c) Kardia Mobile is an earlier version (than KardiaBand); the latter works with Apple Watch only.
(d)
(i) Latin-English dictionary:
* cor (noun neuter): "1: (anatomy) heart
2: (figuratively) soul, mind"
https://en.wiktionary.org/wiki/cor
(ii) English dictionary:
* cardio- (prefix; from Ancient Greek kardía heart)
https://en.wiktionary.org/wiki/cardio-

choi

(3)
(a) In English, electrocardiogram is abbreviated as either ECG or EKG, interchangeably. (In fact, the en.wikipedia.org page for electrocardiogram  uses both in the same page! --presumably by different writers.)  In this posting,it is also interchangeable (because I have used EKG throughout my life, but most American medical literature uses ECG).
(b) In Taiwan, it is EKG exclusively. Wge? I was told back then that German language uses k for c. Correct, but that left me an impression Germans invented EC
(c)
(i) electrocardiography
https://en.wikipedia.org/wiki/Electrocardiography (section 1 History:
("An initial breakthrough came when Willem Einthoven, working in Leiden, the Netherlands, used the string galvanometer (the first practical electrocardiograph) he invented in 1901")
(ii) Willem Einthoven
https://en.wikipedia.org/wiki/Willem_Einthoven
(1860 – 1927; a Dutch physician; invented the first practical electrocardiogram (ECG or EKG) in 1903 and received the Nobel Prize in Medicine in 1924 for it [alone]; His father was of Jewish [which might explain his surname] and Dutch descent)
(d) Dean Jenkins, A (Not So) Brief History of Electrocardiography. ECG Library, first written in 1996 and last updated in 2009
https://ecglibrary.com/ecghist.html

Quote:

"1893  Willem Einthoven introduces the term 'electrocardiogram' at a meeting of the Dutch Medical Association. (Later he claims that [London physician Augustus D] Waller was first to use the term). Einthoven W, Nieuwe Methoden voor Clinisch Onderzoek [New methods for clinical investigation]. Ned T Geneesk 29 II: 263-286, 1893

"1912  Einthoven addresses the Chelsea Clinical Society in London and describes an equilateral triangle formed by his standard leads I, II and III later called 'Einthoven's triangle.' This is the first reference in an English article I have seen to the abbreviation 'EKG'. Einthoven W, The Different Forms of the Human Electrocardiogram and Their Signification. Lancet 1912(1):853-861

(e)
(i) Ludwig van Beethoven
https://en.wikipedia.org/wiki/Ludwig_van_Beethoven
(1770 – 1827; pronunciation)

was not Jewish.
(A) th (digraph)
https://en.wikipedia.org/wiki/Th_(digraph)
(section 5 Alveolar stop /t/  )
(B) digraph (n): "the definition of a digraph is a combination of two letters that make one sound. An example of a digraph is the combination of c and h in the word china."
LoveToKnow Corp, undated
www.yourdictionary.com/digraph
* Accent falls on the first syllable, where the vowel is pronounced the same as eye.
* The merriam-webster.com gives two more example: ea in bread and ng in sing.
(ii) (writer does not ideNtify him- or herself), Ludwig van Beethoven Biography. undated
http://www.lvbeethoven.com/Bio/BiographyFamily.html
("Beeth means 'beetroot' and Hoven is the plural of 'Hof,' meaning 'farm'. Beethoven is therefore 'beetroot farms' ")
(A) beetroot
en.wikipedia.org/wiki/Beetroot
(B) Dutch-English dictionary
* hof (noun masculine; plural: hoven): "yard"
https://en.wiktionary.org/wiki/hof
(C) I can not find a dictionary for the word "beeth." However, the writer confuses Dutch and German. The writer capitalizes the first letter of the nouns Hof and Hoven, underlying the belif these are german nouns. But Hof in German has a different plural form.

German-English dictionary:
* Hof (noun masculine; plural: Höfe): "4: (by extension) farm
https://en.wiktionary.org/wiki/Hof
(iii)
(A) Alessandra Comini, The Changing Image of Beethoven; A study in mythmaking. Santa Fe, NM: Sunstone Press, 2008, , at page 15
https://books.google.com/books?i ... 0origin&f=false
("Beethoven. We are obliged to stop in front of the name itself even before we start our exploration of the Beethoven mystique. Not because of its origin -- Flemish; or its meaning -- mostly probably 'beet yard' ")
(B) If Beethoven Was German, then Why Did He Have the Dutch 'van' Beethoven Instead of the German 'von' Beethoven?  Ask FunTrivia
http://www.funtrivia.com/askft/Question64860.html
(karl2m" on Aug 19, 2008: "I am Flemish and I live close to the area where Van Beethoven's grandfather was from. The meaning of his name is very simple: 'van' is Dutch for 'from' and 'beethoven' can be split into two words: 'beet,' which means beet, and 'hoven,' which means gardens or fields. So basically Ludwig Van Beethoven means 'Lewis (or Lodewijk or Louis) from the beet fields.' In German, his name would have been something like "Ludwig von Rubenhoffen.'  Having said this, legend has it that in the town of Boortmeerbeek, near Mechelen, there is a tavern where Van Beethoven's grandfather still has an unpaid bill. Next time I go cycling in that area I'll check it out.")

choi

(4) EKG in a nutshell
(a) https://en.wikipedia.org/wiki/Electrocardiography
(section 4 Electrodes and leads: "A 'lead' is not the same as an 'electrode.' * * * Since leads can share the same electrode, a standard 12-lead EKG happens to need only 10 electrodes". view the diagram of the transverse section of a human body ABOVE section 4.3 Precordial leads; section 6        Interpretation, section 6.1 Theory: The theory is rooted in electromagnetics and boils down to the four following points)

Read the four points, but nothing else in this Wiki page.
(b) Diane R Karius, ECG Primer: The Leads of a 12-Lead ECG. Kansas City University of Medicine and Biosciences (KCU), undated
https://courses.kcumb.edu/physio/ecg%20primer/ecgleads.htm
(i) This explains "Einthoven's triangle" mentioned in quotation 2 of paragraph (d).
(ii) This also explains why paragraph (2)(b) requires a user to place fingers of left hand and of right hand on the right electrodes (at two ends of a strip), to succeed in obtaining Lead I.
(iii) KCU is a PRIVATE university since 1916.
(iv) As you can see, Lead I is very limited in scope, compared to gold-standard 12 lead EKG. Three-lead and 5-lead EKG are also used, the latter in intensive care unit (ICU), (In some areas of United States, an ambulance uses 3-lead EKG, whereas in some other areas, an ambulance uses the 12-lead one, where paramedics are capable of diagnosing myocardial infarction in the field (without a physician), radio a hospital, and transports a patient directly to catheterization lab to distend a coronary artery -- from 911 dispatch to catheterization in less than 45 minutes.)

choi

(5) Lead I is only good for diagnosing atrial fibrillation, and that is what AliveCor recommends its products for.
(a) "Fibrillation is the rapid, irregular, and unsynchronized contraction of muscle fibers. * * * There are two major classes of cardiac fibrillation: atrial fibrillation and ventricular fibrillation."  en.wikipedia.org.

A heart chamber in fibrillation can not pump blood.
(b) Mairesse GH, Screening for Atrial Fibrillation: a European Heart Rhythm Association (EHRA) Consensus Document Endorsed by the Heart Rhythm Society (HRS), Asia Pacific Heart Rhythm Society (APHRS), and Sociedad Latinoamericana de Estimulacion Cardıaca y Electrofisiologıa (SOLAECE). Europace, 19: 1589–1623 (online publication July 5, 2017)
https://academic.oup.com/europac ... 21365181/eux177.pdf
(Table 4, at page 1598)

Sensitivity and specificity address, respectively, issue of false positive  and false negative.