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Next generation point of care device in Medicine Series: Wallet ECG


Dr WONG Kwun Bun
Associate Consultant, PWH, A&E

ECG in Wallet

Willem Einthoven (21 May 1860 – 29 September 1927) invented the first practical electrocardiogram in 1895 and received the Nobel Prize in Physiology or Medicine in 1924. Personal-use ECG monitors usually give a close reading of your heart rhythm and rate. They may have one or two leads, or points of contact on your body. Clinical or hospital-grade ECGs, on the other hand, use 12 leads, so they’re more sensitive.

Picture Source: Google Images. Disclaimer: The HKSEMS has no conflict of interest with any of the manufacturer of any wearable device company on the market. The HKSEMS did not receive and is not receiving any sponsorship from any commercial companies producing wearable devices. All the picture(s) shown are extracted from public sources on the internet. 

Given increasing use of direct-to-consumer wearables and medical devices, important questions regarding the utilization of such devices and their features in clinical practice arise. In an Apple sponsored multicenter study of 70 AF and 70 sinus rhythm (SR) patients, it was determined that the ECG app generated waveform had morphologic equivalence to Lead I ECG for 98.4% of AF and 100% of SR patients; only 0.8% were excluded for analysis due to artifact. (1) A study of 419,297 participants were monitored for irregular rhythm by Apple Watch. 2161 participants (0.52%) received notifications of irregular pulse. Among participants who received notification of an irregular pulse, 34% had atrial fibrillation on subsequent ECG patch readings and 84% of notifications were concordant with atrial fibrillation. (3)

FDA has approved the personal electrocardiogram (ECG) technology. The product(s) currently available is an ECG machine as thin and light as a credit card and records an accurate, medical-grade EKG in seconds. The Card detects six types of arrhythmias, AFib, Bradycardia, Tachycardia, PVCs, Sinus Rhythm with SVE, and Sinus Rhythm with Wide QRS, and connects to your phone/tablet. It may be beneficial for accessibility challenges to quality healthcare in the country and COVID related infection fears, the portable and technology-enabled ECG device will help deliver affordable and convenient heart care without visiting a hospital.


There are still several challenges of the smartwatch and wallet ECG , the price, sensitivity and specificity, diagnosis of different rhythm and single lead issue. Detection of atrial arrhythmias in such a population could create anxiety and exposure to unnecessary therapies and possible complications.


  1. H. Calkins, G. Hindricks, R. Cappato, Y.H. Kim, E.B. Saad, L. Aguinaga, et al.2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary. J Interv Card Electrophysiol., 50 (1) (2017), pp. 1-55


  3. Marco V. Perez, M.D., Kenneth W. Mahaffey, M.D., Haley Hedlin, Ph.D Large-Scale Assessment of a Smartwatch to Identify Atrial Fibrillation N Engl J Med . 2019 Nov 14;381(20):1909-1917.

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