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Hospital Healthcare Europe

Remote monitoring of implanted cardiac rhythm management devices


20 July, 2010  

Follow-up information can be transferred to the physiologist and cardiologist without the patient leaving home – benefiting the patient in time, travel and anxiety and allowing expert carers to use their time more efficiently

Dr Chris Plummer
Consultant cardiologist
Freeman Hospital,
Newcastle-upon-Tyne, UK

Since the first permanent pacemaker was implanted in 1958, the number and complexity of cardiac rhythm management (CRM) devices implanted into patients has increased exponentially, along with the evidence showing improvements in quality of life and reduction in mortality. Now each year in Europe, more than 900 pacemakers per million population are implanted for bradycardia, 130/million/year implantable cardioverter defibrillators (ICDs) are implanted to prevent sudden cardiac death from ventricular tachyarrhythmias and more than 90/million/year devices are implanted to resynchronise the heart and treat heart failure.

Follow-up of implanted devices
Implantation of one of these devices involves the placement of one or more leads into the heart through the central venous system. This is then attached to the device containing a battery with detection and treatment circuitry which is implanted under the skin. Implantation is only the start of treatment. Following up patients and their devices is an integral part of this process and is required to maintain patient safety and optimise device performance. Follow-up has become increasingly complex and time-consuming with the increasing numbers and functionality of implanted systems. Conventional device follow-up is performed in a booked outpatient clinic, interrogating the device using radio-frequency telemetry via a wand placed over the device. Data on device function including battery longevity, sensing of intrinsic heart rhythm, lead impedance and threshold for pacing are recorded as is the patient’s intrinsic heart rate, activity and any significant heart rhythm abnormalities.
Most clinic visits are scheduled and do not result in changes in device programming or clinical care. Most unscheduled visits occur when the patient has symptoms which may be attributable to device malfunction. A new generation of implanted heart rhythm and haemodynamic monitors is being developed which can be incorporated into a rhythm management device or implanted separately when indicated. Some systems also have the capacity to include data from external monitors such as weight and blood pressure.

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Remote monitoring
Remote monitoring of CRM devices is the transfer of follow-up information from the device to the physiologist and cardiologist without the patient leaving home. Remote device monitoring has a long history in the United States. Large geographical distances led to the development of transtelephonic monitoring with the transmission of very limited ECG and pacemaker battery information over standard telephone lines. In recent years, this technology has developed into more sophisticated telemetry with on- or off-line analysis. This has significant efficiency advantages: patient travelling is reduced, clinic time is reduced and patients can transmit data at a time convenient for them with data reviewed off-line in a ‘virtual clinic’ at an efficient time. For some devices, this process requires the patient to initiate the remote follow-up by placing a wand over the device, on a planned date or because of symptoms. The next technological development was automatic monitoring – the device wirelessly uploads data to a monitor either routinely (e.g. each night) or as soon as a problem is detected. The data are then transmitted over a standard telephone line or mobile telephone network to a secure server which can be accessed by the clinical team at any time, but they are specifically alerted by any data outside pre-specified limits. This has a number of immediate advantages and has the capacity to change the paradigm of follow-up – from monitoring the device to monitoring the patient. We are now able to move from regular attendance at clinics to frequent unobtrusive monitoring of device, patient and disease. For the first time, this allows us to see patients only when they need to be seen and to intervene before the onset of symptoms to prevent clinical problems and emergency hospital admissions. Studies with this technology have shown significantly earlier detection not only of device problems[1] but also the onset of arrhythmias such as atrial fibrillation,[2] allowing early initiation of heart rate control and anticoagulation, thereby potentially reducing subsequent admissions with heart failure or stroke. Heart failure devices (CRT-P and CRT-D) are now available which can monitor patients’ physical activity, fluid status and/or haemo­dynamic parameters allowing early intervention in heart failure and reduction in emergency admissions. There are also new implantable devices for patients without rhythm management indications which can monitor these parameters in the same way. Patient surveys have shown that they prefer routine remote monitoring, with visits to the clinic limited to the occurrence of clinical or device problems. At present, there is no commercially available system which allows remote reprogramming of devices. However, the technology exists to do this and safety evaluations are underway. This has the potential to reduce in-clinic follow-up further by limiting it to wound and other physical problems.

Indications
Remote monitoring technology is applicable to all new and many already implanted devices – pacemakers, ICDs and implantable loop recorders, although wireless communication is possible only with wireless-enabled models. The patients with most to gain are those whose clinic visits can be safely reduced e.g. elderly, immobile patients living far from the clinic with a pacemaker implanted for brady­cardia with which there are no problems, and those who would benefit from closer monitoring e.g. a heart failure bi-ventricular defibrillator (CRT-D) patient with difficult to control symptoms or frequent arrhythmias. Other patient groups with clear benefit are younger working patients where taking time off work is problematic and older patients who need either ambulance transport or transport from a relative to attend the clinic.

Health economics
Remote monitoring has the potential to use healthcare provider time more efficiently – it allows screening of data by less highly trained personnel with problems passed to specialists who can review data at a convenient time. It also allows data to be shared by different clinical teams – for example, electrophysiologists and heart failure specialists. Remote monitoring systems can reduce follow-up in those who do not require it and thereby allowing increased follow-up of patients who will benefit in safety, symptoms and reduced emergency hospital admissions. Cost-effective­ness analyses have been performed which have shown reduced numbers of clinic visits,[3] reduced patient travel costs,[4] increased clinic efficiency and earlier detection of clinically significant effects.[1,2 ]Disease management – the anticipation of patient decompensation by remote monitoring from an implanted CRM or monitoring-only device – has the potential to avoid emergency admissions. This will improve patient safety and reduce healthcare costs. An ongoing multicentre cost-effectiveness study (EuroEco) should provide further European data in the next two years.

Manpower implications
There is a shortage of appropriately trained cardiac physiologists in Europe to provide follow-up services for an expanding population of device patients. Remote follow-up has the potential to allow physiologists and cardiologists to use their time more efficiently and flexibly, reviewing patient records faster and at an efficient time which does not need to be pre-arranged. More importantly, it has the capacity to focus the most highly trained physiologists’ follow-up capacity on patients with problems while the automatic nature of data review in other patients may allow others to review patient and device data safely and efficiently. Remote monitoring is therefore an essential component of the delivery of evidence-based device therapy.

Benefits for the patient
Remote device follow-up is an important new technology which has the potential to improve patient care and safety and increase the efficiency of hospital device services. It allows patient care to switch emphasis from device follow-up to disease monitoring, allowing early intervention to prevent decompensation and emergency hospital admission. Adoption of this technology will facilitate the expansion of evidence-based cardiac rhythm management device therapy for  patients to reduce mortality and improve quality of life.

References
1. Nielsen et al. Europace 2008;10:729-35.
2. Ricci et al. Europace 2009;11:54-61.
3. Heidbuchel et al. Europace 2008;10:351-7.
4. Fauchier et al. PACE 2005 28;s1:S255 -S259.