Background

The number of implantations of electronic implantable medical devices in the cardiovascular area has grown since their introduction in 1958 . In France, 65,000 pacemakers are implanted every year. The number of implantable defibrillators rose from 2700 in 2003 to 13,000 in 2013. These medical devices require regular post-implantation follow-up of patients to ensure that an appropriate response to the patient’s condition is transmitted. Monitoring of battery status is also essential. Currently, conventional monitoring (face-to-face four times per year) does not allow real-time follow-up. Technological advances, with the development of implantable devices with automatic remote monitoring (RM) capability, allow constant surveillance.

RM involves the transmission of data on the status of the device, patient variables gathered by the device and, sometimes, disease-related data, over a network from the patient’s location via a central database to a hospital or physician’s office. RM could also be a solution to the decrease in the number of practitioners envisaged in the coming years as opposed to the predicted increase in the number of patients. The increase in patients can be explained by the ageing of the population and the widening of heart failure indications, thanks to the development of cardiac resynchronization therapy (CRT) devices .

Currently, five manufacturers offer monitoring interfaces, which provide follow-up of 20,000 patients in France . These monitoring interfaces exhibit differences. The clinical and organizational impact of RM has already been supported by a large number of publications. Although the implantation of electronic medical devices is currently covered by health insurance, the deployment of RM remains subject to the supervisory authorities of the RM act itself in France, unlike in other countries. Validation of the act may evolve in the coming years and should be the subject of robust medico-economic studies.

This review firstly offers a reminder of the principle of RM. Secondly, the organizational and regulatory aspects of RM will be discussed, followed by medico-economic aspects inherent to RM.

The principle of cardiac remote monitoring

The principle of cardiac RM was first mentioned in the 1970s by Dreifus and Pennock . With the recent progress in telecommunications, RM has rapidly become a powerful tool in the rhythmology department. Initially, active systems were developed but were soon replaced by automatic transmission, which increases patient observance naturally.

Implantable devices with automatic RM capability are equipped with an antenna circuit and transmit daily information as electromagnetic signals to a transmitter located in the patient’s home. The transmitter automatically transmits this information after encoding via the mobile phone or landline network to the secure server managed by the manufacturer. The analysis of information is then possible from the cardiology centre due to a secure internet portal. Two different types of data are transmitted to the implant centre. Firstly, data on the medical device integrity are available: battery status; recording and stimulation capacity; and measurement of impedance lead. Secondly, cardiac events in patients are transmitted (see later). All abnormalities are reported by e-mail, facsimile, telephone and/or short message service (SMS) to the health professional in charge of monitoring.

There are currently five manufacturers offering RM systems ( Table 1 ), which operate differently ( Table 2 ), especially in terms of location of data storage and encoding used. The notification of alerts, as well as the management of end of monitoring and registration of new patients, can be configured according to the needs of the rhythmology centre. The Home Monitoring ^® system does not allow the patient to activate the transmission. With the exception of Boston Scientific, all systems use the mobile network. As transmissions need energy from the device, RM reduces the lifetime of implants by 1–6 months, according to the prosthesis. The Latitude ^® system avoids this pitfall due to the transmitter querying the prosthesis that supplies the energy.

Data storage is not carried out in France, except for the systems developed by Sorin and Boston Scientific. All systems authorize access by the treating physician. Regarding the rules of confidentiality, many countries allow manufacturers to dispose of the patient data; this is not the case in France, where patient data are confidential and can only be consulted by the rhythmology department.

The feasibility and reliability of RM has been demonstrated for a number of manufacturers across several publications . In these studies (Biotronik, Medtronic, Boston Scientific), messages were received in their entirety and were delivered in < 1 minute to the rhythmology centre in > 90% of cases . The correlation coefficient between the transmitted data and those collected by device querying was 95% . Three manufacturers allow a wire-line transmission, which is useful in areas not covered by the Global System for Mobile Communications (GSM) network, covering 99% of the metropolitan area ( Table 2 ).

Initially, RM systems transmit data on the prosthesis and probe integrity, as well as on cardiac events in patients. The reports allow detection of:

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  failure of the implants to charge and deliver appropriate therapy;

  
  
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  inappropriate ventricular tachycardia and intermittent T-wave oversensing;

  
  
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  a change in lead impedance that could reflect a lead fracture.

As a function of the medical devices implanted in patients, data are different, and the complexity of the implants increases the amount of data transmitted. With the development of CRT devices, new variables have been proposed to follow-up patients with heart failure . Weight and blood pressure are particularly useful for monitoring aggravation of heart failure. Pulmonary artery pressure is also followed up with these new devices and gives important information for rapid patient management. All the data downloaded from these increasingly complex devices need careful management and highlight the importance of a well-organized RM procedure.