br What is the best pacing algorithm for vasovagal syncope
What is the best pacing algorithm for vasovagal syncope?
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Introduction The number of implantations of cardiovascular implantable electronic devices (CIEDs), including permanent pacemakers (PPMs), implantable cardioverter defibrillators (ICDs), and cardiac resynchronization therapy (CRT) defibrillators (CRT-D) is increasing annually in Japan as well as in Western countries (Fig. 1). The follow-up of the patients with CIEDs must be individualized in accordance with the patient׳s clinical status and conducted by a physician fully trained in device follow-up. Current guidelines suggest 1 or 2 follow-up evaluations per year for stable patients with PPMs and more than that for patients with defibrillators . As the number of patients with chronically implanted CIEDs grows, the amount of follow-ups also increases, placing an increasing burden on device clinics. Remote monitoring (RM) of CIEDs is expected to provide a solution to this equol problem.
Systems for RM In Japan, the methods of data transmission between the device and the communicator, as well as between the communicator and the Internet, vary among the device manufacturers. Moreover, the transmission frequencies are also different. Table 1 summarizes the characteristics of the 5 systems currently available in Japan: Biotronik׳s Home Monitoring, Boston Scientific׳s LATITUDE, Medtronic׳s CareLink, St. Jude Medical׳s Merlin.net, and Sorin׳s SMARTVIEW. Some of them transmit the data automatically as illustrated in the upper panel of Fig. 2, whereas others require the interrogation to be initiated by the patient by placing a special wand in the vicinity of the CIED, as depicted in the lower panel of Fig. 2. The third generation mobile phone network (3G network) has been used to transmit the data to the data server. Wireless transmission of the data between the device and the communicator is performed using a radio frequency range assigned for medical implant communications (402–405MHz). From the safety standpoint, automatic wireless data transmission from the CIED to the communicator is ideal. Within the wired transmission design, a patient can send the data manually only when he or she senses abnormalities such as palpitation or shock. In this regard, the largest advantage of RM is the possibility to transmit asymptomatic events. The physician can receive such alert messages via e-mail, fax, etc. Once the data have been transmitted to a data server, the physician can also use the Internet to access this information and, if needed, to arrange a hospital visit. However, CIED programming cannot be performed remotely at present.
The expected role of RM in overcoming the problems of CIED therapy Lead dysfunction is a major concern in CIED therapy. Spencker et al.  reported that the automatic RM surveillance system enables physicians to detect severe lead problems early and to react quickly. They studied 54 patients who had to undergo resurgery because of malfunctions of the ICD leads. Eleven of these patients had RM systems that interrogated their devices every night. The rates of inappropriate shocks and symptomatic pacemaker inhibition due to oversensing were compared with those in 43 patients without the remote surveillance. RM systems sent alert messages in 91% of all incidents, whereas changes in the pacing impedance were notified only in 18%. Remarkably, 80% of the patients were asymptomatic at the first onset of oversensing. Inappropriate shocks occurred in 27.3% of the patients in the RM group compared to 46.5% in the non-RM group (P=not significant). The mean time between the last ICD interrogation and the event message was 54 days, or about 56 days before the next scheduled visit. Thus, 56 days of reaction time were gained to avoid adverse events. The authors concluded that RM may be useful for avoiding inappropriate shocks due to lead failure and T-wave oversensing. Similar studies demonstrating the capability of RM to promptly detect lead dysfunction were reported [2–5].