PARIS – Results of two randomized controlled trials appear to solidify the safety of remote monitoring of implantable cardioverter defibrillators, and one of the studies showed a significant decrease in the number of patients receiving inappropriate shocks in the remote-monitoring group.

Manufacturers of ICDs currently recommend in-clinic follow-up every 3 months to detect clinical events or device malfunctions. With increasing numbers of people receiving ICDs to prevent sudden cardiac death from rhythm disturbances, investigators are testing ways to avoid the time constraints of so many in-clinic visits by remotely transmitting information from the device via telephone from the patient’s home. Most ICDs now have this capability.

The two randomized controlled trials support findings from patient registries in Europe and in the United States, where remote monitoring is common.

In the yearlong Evaluation of Tele Follow-up (EVATEL) trial, 1,501 patients at 30 French centers were randomized to in-clinic follow-up at the implant center every 3 months or to remote transmission of data to the implant center every 3 months. The study included four types of ICDs.

Results showed no significant difference between groups in the time to first major cardiovascular event or in the rates of major cardiovascular events (death from all causes, cardiovascular-related hospitalization, or inappropriate or ineffective shocks), Dr. Philippe Mabo and his associates reported at the annual congress of the European Society of Cardiology .

Rates of this composite end point were 28% in the remote-monitoring group and 29% in the control group in an intent-to-treat analysis, showing that home monitoring was not inferior to in-office monitoring. In a per-protocol analysis, the primary end points were seen in 28% and 30% of the groups, respectively, but the confidence interval was too wide to claim that there was no significant difference between groups, said Dr. Mabo of Rennes (France) University Hospital.

The trial could not demonstrate an impact on preventing major clinical events, but it did reinforce the safety of remote monitoring, he said.

The study also found a significant 27% reduction in the number of inappropriate shocks delivered by the ICDs, from approximately 8% in the control group to 5% in the remote-monitoring group.

Among several weaknesses of the study, there were no interventions planned in response to monitoring, said Dr. Angelo Auricchio, who commented on the study in the presentation session. Using the data to intervene in problems with ICDs is "the greatest advantage" of the technology, so it is not surprising that the EVATEL study did not show a major impact on cardiovascular end points, said Dr. Auricchio of the Fondazione Cardiocentro Ticino, Lugano, Switzerland.