To the Editor: Cardiac implantable electrical devices (CIEDs) are the most effective method of treating and diagnosing several different kinds of arrhythmia and heart failure. It is necessary for a clinician to evaluate the parameters of the device to ensure safety and efficacy during the procedure. Traditionally, parameter testing and programming are performed by the manufacturer's clinical service technician on- site in the Cath-lab. However, after the outbreak of the corona virus disease-2019 (COVID-19), the manufacturer's clinical service technicians are not allowed access to the Cath-lab and ward. Solving the problem of parameter testing and programming is crucial. A novel non-contact interrogation system based on China Telecom 5G data transmit Module with Merlin Programmer 3650 Software version 20.1.1 rev3 (St. Jude Medical, USA) provides a useful solution without any physical contact with the manufacturer's clinical service technician during CIED implantation and reduces the risk of COVID-19 infection. This novel remote interrogate system is composed of an off-site device installed remote interrogation (RI) software called 5G cloud follow-up, a Merlin Patient Care system-3650 programmer (version 20.1.1 rev3) equipped with a 5G data transmit module in the Cath-lab, and a central server located at the secure data center [ Figure 1]. Figure 1:
Description of the mechanism for Cloud follow-up technology system. (A) China Telecom 5G Remote control server. (B) Remote control Device (Outside the hospital). (C) China Telecom 5G data transmit module with Abbott Merlin Programmer 3650 system (In Cath-lab). 1: Technician enters the individual password and gets the mobile short message service(SMS) random verification code to log in to the remote interrogate application (APP). 2: Technician chooses the programmer in target Cath-lab and data transfer between the remote control device and the 5G remote control server. 3: Cath-lab staff connects the 5G signal transmit Module with Abbott Merlin Programmer 3650 system. 4: Data transfer between 5G remote control server and programmer in Cath-lab. 5: Real-time communication between the technician and medical staff via phone.
This system allows the manufacturer's clinical service technician to perform parameter testing and programming in real time from an off-site location in accordance with the CIEDs implant procedure. The RI software has appropriate security procedures to authenticate the technician to connect the Merlin Patient Care system-3650 programmer.
In addition to the technician's individual secret identification password, the secure data center also sends a dynamic verification code to the technician after the Cath-lab staff confirms that the implantation procedure has begun. Realtime communication between the technician and medical staff also increases the security of non-contact parameter testing and programming.
This study continually enrolled 110 CIEDs implanted patients admitted to Beijing Anzhen Hospital, Capital Medical University, from August 2020 to March 2021. Among the enrolled cases, 59 patients were interrogated by technicians with their physical presence. In the other 51 cases, we used the non-contact interrogated system. The enrolled patients received 92 dual-chamber pacemakers, five single-chamber pacemakers, three single-chamber implantable cardioverter-defibrillator (ICD), five dual-chamber ICDs, and five cardiac resynchronization therapy (CRT) devices. In the physical presence group, two single-chamber pacemakers and 50 dual-chamber pacemakers, two single-chamber ICDs, two dual-chamber ICDS, and three CRT devices were implanted. In the non-contact group, there were three single-chamber pacemakers and 42 dual-chamber pacemakers implanted as well as one single-chamber ICD, three dual-chamber ICDs, and two CRT devices.
Quantitative data are expressed as mean ± standard deviation. Qualitative data are expressed as frequency (percentage [%]). Two independent sample
t-test and paired t-test were used for statistical analysis of the two sets of quantitative data. The chi-squared test was performed to assess differences in qualitative data between the two groups. Results were considered significant for two-tailed P ≤ 0.05. Statistical analysis was performed using the Statistical Package for the Social Sciences ver. 26 software (SPSS, Chicago, IL, USA).
The baseline demographic data were acquired from the medical database of Beijing Anzhen Hospital. The parameters of left ventricle ejection fraction (LVEF) were synthesized and controlled by a validated and standardized protocol at Beijing Anzhen Hospital, Capital Medical University. The interrogation was performed by the assigned manufacturer's technicians when patients were admitted and discharged for the purpose of avoiding individual bias. The confounding factors included age, sex, body mass index (BMI), hypertension, diabetes, coronary artery bypass grafting (CABG), and clinical serum indicators.
We found that the demographic data in gender, age, BMI, CIED type, indication, baseline LVEF, CABG, diabetes, hypertension, hemoglobin, high-sensitivity C-reactive protein, uric acid, Scr (mmol/L), and angiotensin-converting enzyme inhibitor use between the physical presence group and the non-contact group were not statistically significantly different (
P > 0.05).
The parameters of sensing, threshold, and impedance regarding the right atrium (RA), right ventricle (RV), and left ventricle (LV) were not statistically significantly different between the two groups in real time as well as after 1 month (
P > 0.05).
RA impedance, RV impedance, and LV impedance had higher values in real time than 1 month later in the non-contact group, which is statistically significant (
P < 0.05). There is no statistically significant difference in the other parameters between the two groups ( P > 0.05).
Shut-open door frequency was higher in the technician physical present group than the non-contact group (
P < 0.05). Procedure time and device malfunction were not significantly different between the two groups ( P > 0.05). Infection occurred at the same frequency in the two groups, and there was no statistically significant difference in test results.
Nowadays, the prospect of RI is getting wider than before, especially with the expanded indications for ICD or CRT dramatically increased in the population of patients requiring ongoing follow-up. According to the previous study, the author believes that RI or monitoring will take the place of traditional physical present follow-up. It can be used to monitor commodities if relevant data are stored in the device.
It was first introduced in 1971 when the remote monitor system was applied via transtelephonic monitoring (TTM) for pacemakers. In accordance with improvements in technology and the recognition of the importance of the management of CIEDs, RI technology was first used in this way in the late 1990s. RI is a superior technology to TTM because it can retrieve diagnostic data and modify the functional parameters of CIEDs. There are several clinical trials of RI that have validated its safety and effectiveness. In 2009, George H. Crosseley published The Pacemaker Remote Follow-up Evaluation and Review study; this study enrolled 980 patients. They were assigned in a 2:1 ratio to undergo RI
vs. a control group with conventional follow-up. After 12 months of follow-up, results showed that atrial fibrillation, ventricular arrhythmia, device/lead malfunction, and battery depletion events were detected sooner in the RI group. Among patients undergoing RI, 446 of 676 events (66%) were detected, and only three of 190 events (2%) were detected in the control group. Another two prospective studies evaluated RI technology as used in ICD patients.  The authors reported the results were similar to those of the Pacemaker Remote Follow-up Evaluation and Review study. [2,3]
The clinic staff in these studies found the data to be reliable and sufficient for evaluating device function and detecting arrhythmia while reducing the frequency of the traditional follow-up. RI technology has specific superiority over physically present evaluation in an emergency room or remote area hospital. Neuenschwander
et al reported that, in an emergency department, when the RI was used, it was associated with significant reductions in the duration of CIED device evaluation and time elapsed before a treatment decision was made. Several studies have approved that RI technology not only reduces the clinic follow-up but also has the potential to improve clinical outcomes among stable patients by providing early detection of adverse events.  Meanwhile, there was strong proof which indicated that over 90% of clinically significant events were captured using remote monitoring.  Another worthwhile tissue is RI technology could save 81 hours for a physician a year when remote interrogate 100 patients. [6,7] 
Unlike a traditional RI system, this novel non-contact interrogate system not only allows remote CIEDs monitoring but also remote testing and programming. This system reduces the degree of personnel contact and minimizes personnel exposure to COVID-19 infection. This is a new type of RI technology, and it shows a unique advantage in faster data transmission and higher data security compared with the other RI systems used at present. It uses 2048-bit Rivest-Shamir-Adleman (RSA) asymmetric key exchange and autonomous peer to peer data transfer protocol building on the advanced encryption standard encryption mechanism and anti-cracking measures to ensure communication and client security.
This study has several limitations. First, the sample size was relatively small; Second, the duration of follow-up was relatively short; Third, the number of observed variables was relatively small.
In our study, we observed that results are similar to those of previous studies. As this novel non-contact system showed stability and quick data transmission speed, we think it is reliable in CIEDs implantation procedures.
The authors thank all the medical staff working in the 33rd ward, Beijing Anzhen Hospital, Capital Medical University, and the technician from Abbott.
Conflicts of interest
1. Crossley GH, Chen J, Choucair W, Cohen TJ, Gohn DC, Johnson WB, et al. Clinical benefits of remote versus transtelephonic monitoring of implanted pacemakers. J Am Coll Cardiol 2009;54:2012–2019. doi: 10.1016/j.jacc.2009.10.001.
2. Schoenfeld MH, Compton SJ, Mead RH, Weiss DN, Sherfesee L, Englund J, et al. Remote monitoring of implantable cardioverter defibrillators: a prospective analysis. Pacing Clin Electrophysiol 2004;27:757–763. doi: 10.1111/j.1540-8159.2004.00524.x.
3. Joseph GK, Wilkoff BL, Dresing T, Burkhardt J, Khaykin Y. Remote interrogation and monitoring of implantable cardioverter defibrillators. J Interv Card Electrophysiol 2004;11:161–166. doi: 10.1023/B:JICE.0000042356.52369.89.
4. Neuenschwander JF II, Girsky M, Peacock WF IV, Stirman T, Magdy M, Daugherty JC Jr, et al. 45 Remote device interrogation in the emergency department study shows decreased time to interrogation and disposition decision. Ann Emerg Med 2015;66:S16. doi: 10.1016/j.annemergmed.2015.07.074.
5. Scholten MF, Thornton AS, Theuns DA, Res J, Jordaens LJ. Twiddler's syndrome detected by home monitoring device. Pacing Clin Electrophysiol 2004;27:1151–1152. doi: 10.1111/j.1540-8159.2004.00599.x.
6. Spencker S, Coban N, Koch L, Schirdewan A, Müller D. Potential role of home monitoring to reduce inappropriate shocks in implantable cardioverter-defibrillator patients due to lead failure. Europace 2009;11:483–488. doi: 10.1093/europace/eun350.
7. Raatikainen MJ, Uusimaa P, van Ginneken MM, Janssen JPG, Linnaluoto M. Remote monitoring of implantable cardioverter defibrillator patients: a safe, time-saving, and cost-effective means for follow-up. Europace 2008;10:1145–1151. doi: 10.1093/europace/eun203.
8. Elsner CH, Sommer P, Piorkowski C, Taborsky M, Neuser H, Bytesnik J, et al. A prospective multicenter comparison trial of home monitoring against regular follow-up in MADIT II patients: additional visits and cost impact. Comput Cardiol 2006;33:241–244.