Scratching the surface: electrocardiograms and promising cardiac medical devices

Submitted by Jan Ash on Mon, 02/08/2021 - 10:41
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Coupled with the technological advances over recent years, significant developments of diagnostic and monitoring platforms have alleviated pressures faced by front line doctors (1). Within the field of cardiology, the ongoing sophistication of medical devices has improved patient quality of life for a range of different cardiovascular-related illnesses such as ischaemic heart disease and hypertensive diseases. A wealth of devices such as pacemakers, cardioverter-defibrillators, and electrocardiogram machines have undergone substantial upgrades over recent years through miniaturisation, remote monitoring and biological supercapacitors (2,3).

Electrocardiogram devices such as loop recorders are intermittent long-term monitors that detect cardiac arrhythmia (4). In patients experiencing syncope or atrial fibrillation (AF), loop recorders offer an advantage in continuously monitoring relevant arrhythmias. By tracking these abnormalities through predefined algorithms and registration of ECG during onset, loop recorders can reliably document the correlation between symptoms and arrhythmia (5). As patients within this category are at an increased risk of sudden cardiac death, means of diagnosing arrhythmia can improve the management of patients suffering with structural heart diseases or inherited primary arrhythmia syndromes, and reduce mortality rates (6,7).

External loop recorders (ELRs) continuously monitor patients for a lifetime of up to 14 days. However, through technological advancements, ECGs have undergone miniaturisation and can now remotely monitor patient arrhythmia when implanted in a subcutaneous pocket via an incision or injection, during a 20-minute procedure, with a lifetime of up to 3 years (5,8). These advancements in ECG technology overcome other limitations faced by ELRs such as patient compliance when operating the device and the handling of cutaneous electrode patches (9). 

A trial investigating three internal loop recorders (ILRs), evaluated the efficacy of these devices in a population with adult congenital heart disease (ACHD). Of the 119 patients involved, 43 were diagnosed with life threatening conditions, of which 22 were fitted with cardiac devices such as pacemakers and defibrillators (10). Identifying ILRs as potentially life-saving diagnostic devices in preventing patient mortality from ACHD.  ILRs have also shown promise in patients with cryptogenic stroke. The CRYSTAL-AF study on 441 patients showed that ILRs proved superior compared to conventional follow-up for the detection of AF following cryptogenic stroke (11). Furthermore, a similar study using ILRs following a stroke detected 25.5% of the cohort showed signs of AF. As AF is a common cause of stroke and accounts for 25% of all infarcts, these studies suggest ILRs may play an important role in further target investigations of patients with unexplained stroke (8,12).

In conclusion, ILRs have the potential to offer significant improvements over traditional ELR monitoring.. Though they show usefulness through remote monitoring in clinical research and the epidemiology of cardiac arrhythmias, limitations such as accurate ECG monitoring will need to be addressed to improve R-wave sensitivity (13) and further studies will need to be undertaken. An increase in research can provide a wealth of data in optimising these pitfalls to prevent patient fatality through early diagnosis using these devices (14).

The rate at which we are seeing medical devices develop is encouraging, and with new technology being continuously adapted to help improve patient outcomes and quality of life, there is a constant flow of new information being directed at physicians. The Corpus puts together digestible medical education that covers medical devices and pharmacological treatment, allowing physicians to learn at their own pace and in a format that suits them. Contact us today to find out how we can help tailor an educational programme to suit your needs.


1.     Bruining N, Caiani E, Chronaki C, Guzik P, van der Velde E. Acquisition and analysis of cardiovascular signals on smartphones: potential, pitfalls and perspectives: by the Task Force of the e-Cardiology Working Group of European Society of Cardiology. European journal of preventive cardiology. 2014 Nov 1;21(2_suppl):4-13.
2.    World Health Organization, 2015. Systematic review of needs for medical devices for ageing populations: commissioned to the Australian Safety and Efficacy Register of New Interventional Procedures–Surgical (ASERNIP-S) by the World Health Organization (WHO).
3.    Otawova, R., Kamensky, V., Hasenohrlova, P. and Rogalewicz, V., 2015, April. Cost-effectiveness studies on medical devices: Application in cardiology. In International Conference on Bioinformatics and Biomedical Engineering (pp. 163-174). Springer, Cham.
4.    Health Quality Ontario, 2017. Long-Term Continuous Ambulatory ECG Monitors and External Cardiac Loop Recorders for Cardiac Arrhythmia: A Health Technology Assessment. Ontario health technology assessment series, 17(1), p.1.
5.    Galli, A., Ambrosini, F. and Lombardi, F., 2016. Holter monitoring and loop recorders: from research to clinical practice. Arrhythmia & electrophysiology review, 5(2), p.136.
6.    Zimetbaum, P. and Goldman, A., 2010. Ambulatory arrhythmia monitoring: choosing the right device. Circulation, 122(16), pp.1629-1636.
7.    Brignole, M., Vardas, P., Hoffman, E., Huikuri, H., Moya, A., Ricci, R., Sulke, N., Wieling, W., Auricchio, A., Lip, G.Y. and Almendral, J., 2009. Indications for the use of diagnostic implantable and external ECG loop recorders. Europace, 11(5), pp.671-687.
8.    Cotter, P.E., Martin, P.J., Ring, L., Warburton, E.A., Belham, M. and Pugh, P.J., 2013. Incidence of atrial fibrillation detected by implantable loop recorders in unexplained stroke. Neurology, 80(17), pp.1546-1550.
9.    Tanno, K., 2017. Use of implantable and external loop recorders in syncope with unknown causes. Journal of arrhythmia, 33(6), pp.579-582.
10.    Tabassum, R., Okeke, Z., Arif, S., Clift, P., Bowater, S., Thorne, S., Marshall, H., de Bono, J. and Hudsmith, L., 2017. 3 Implantable loop recorders in adult congenital heart disease: a single-centre experience.
11.    Sanna, T., Diener, H.C., Passman, R.S., Di Lazzaro, V., Bernstein, R.A., Morillo, C.A., Rymer, M.M., Thijs, V., Rogers, T., Beckers, F. and Lindborg, K., 2014. Cryptogenic stroke and underlying atrial fibrillation. New England Journal of Medicine, 370(26), pp.2478-2486.
12.    Marini, C., De Santis, F., Sacco, S., Russo, T., Olivieri, L., Totaro, R. and Carolei, A., 2005. Contribution of atrial fibrillation to incidence and outcome of ischemic stroke: results from a population-based study. Stroke, 36(6), pp.1115-1119.
13.    Lee, R. and Mittal, S., 2018. Utility and limitations of long-term monitoring of atrial fibrillation using an implantable loop recorder. Heart Rhythm, 15(2), pp.287-295.
14.    Bisignani, A., De Bonis, S., Mancuso, L., Ceravolo, G. and Bisignani, G., 2019. Implantable loop recorder in clinical practice. Journal of arrhythmia, 35(1), pp.25-32.

Intro paragraph

With an aging global population, research into streamlining medical devices has enabled remote observation of patients with cardiac issues, both symptomatic and asymptomatic. Matt Colborne looks at recent progress.

Author name and role

Matthew Colborne - Corpus Content Team

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