Innovative technologies for the cardiac patient and their effects

Abstract

Writing in the prestigious American journal Science some half a century ago, Norman Holter described a vision where he saw clinicians being able to make ‘long, continuous recordings of physiological phenomena’ from patients ‘with numerous little boxes piling up information about body function’. He predicted ‘full freedom, through elimination of wires, electronic baggage and radio interference’ (Holter, 1961). Well, his vision is now reality. The technology for ambulatory ECG recording, a technique originally introduced by Holter and used for the first time in a clinical setting in 1954 (Maclnnis, 1954), has altered remarkably in the last few years, although you might be hard pushed to notice this in many hospital departments. Signage directing patients to the ‘Tapes Department’ and patient letters requesting their attendance for fitting of a ‘24-hour tape’ are commonplace even though tapes disappeared from most centres over a decade ago. Ambulatory ECG recorders are frequently requested for a traditional 24-hour or 48-hour period even though the pick-up rate in certain circumstances may be low (Kinlay et al, 1996) and modern digital recorders are actually capable of so much more. Patient-activated recorders are issued with variable, but often limited success (Zimetbaum and Josephson, 1998). Following a flurry of developments, a multitude of new recording devices have appeared. Over recent times, I’ve been contacted by the inventor of a ball-shaped ECG recording device that apparently offers great potential as it is ‘easy to hold’ and I’ve been invited to inspect a finger ‘glove’ that detects heart rhythm, blood pressure, oxygen saturation and temperature. A quick search of the web throws up all sorts, ranging from an ‘AF stick’ (Tieleman et al, 2014) to a multi-sensing sticking plaster (Hernandez-Silveira et al, 2015). As described in a previous edition of this journal, mobile phones can easily be adapted to detect the owner’s ECG (Richley and Graham, 2015) and the latest versions of computer-game consoles can remotely monitor pulse rates while a user is playing. In fact, if you’re thinking of dabbling in the heart monitoring industry, it is probably too late to make your fortune, at least in terms of hardware. With this rapid explosion of interest, the effectiveness of these new tools in the clinical setting has yet to be firmly established, though the early signs are encouraging. The detection of paroxysmal atrial fibrillation is one area of particular interest (Turakhia et al, 2015). Ambulatory ECG recording is often performed in patients with a history of cryptogenic stroke with the aim of documenting the presence of atrial fibrillation. In these situations, recording over a period of 30 days or longer has benefits and long-term, continuous recording using unobtrusive, noninvasive devices has potential. Our understanding of atrial fibrillation might well be transformed by these novel recording devices. The true prevalence of atrial fibrillation might be very different to current thinking based on the low-yield techniques used in previous epidemiological studies. It is inevitable that these innovations will disrupt life as we know it in cardiac diagnostic departments. Adhesive patch-based recorders will be more acceptable to patients than numerous electrodes and wires; waterproof products avoid shower dilemmas; disposable units negate infection control issues. The ability of novel devices to link up with mobile phones allows for real-time tracking of the ECG with potential for instant notification of rhythm disturbances. We’re likely to see more monitoring centres popping up, some will be within the current services but perhaps more will be outside of the traditional hospital setting. The ubiquitous, ever-present mobile phone is sure to be key to the future of ambulatory ECG, whether recording directly or acting as a routing device to transmit signals elsewhere for analysis. We might see a shifting of resources from health service-provided kit to patients providing their own devices. Patient choice will be improved in terms of whom they would like to interpret their recordings and from whom they seek their clinical advice. There might even be an improvement in arrhythmia detection rates as patients will inevitably have their phones at hand, rather than languishing in a drawer as is likely to be the case for many of the patient-activated recorders issued today. BJCN