Safer Implanted Defibrillators on the Horizon?
Unnecessary shocks from the heart devices are often distressing, come with their own risks, experts say
The volunteers were randomly placed into one of two groups: standard programming or programming with a long detection interval.
"Every time the heart beats, an electrical activity is recorded by the device. An interval is the time between two consecutives beats. Basically it is the time between two heartbeats. So, a long detection interval simply means a longer period of time to permit recognition of arrhythmias," Gasparini explained.
During an average of 12 months of follow-up, 530 episodes of an arrhythmia were recorded. The long detection group had a 37 percent lower rate of delivered therapies (pacing or shocks) than the standard therapy group, according to the study.
There were no significant differences in mortality or in fainting (syncope) episodes between the groups.
"This study shows that we can decrease inappropriate and unnecessary therapies, and clearly you make people feel better because they're not getting inappropriate or unnecessary therapy, said Dr. Ranjit Suri, director of the electrophysiology service and Cardiac Arrhythmia Center at Lenox Hill Hospital in New York City.
However, Suri said it's not yet clear what the ideal interval time is. The current study doesn't show a benefit in terms of reduced risk of death. Another study, published last December in the New England Journal of Medicine, did find a mortality benefit. But, the interval was longer in that study.
Still, Suri said, doctors could start programming ICDs with longer intervals, and making such a change to the device isn't difficult or time-consuming.
In his editorial, Raitt wrote: "Regardless of whether these programming interventions lead to reduced mortality, the unequivocal reduction in ICD shocks and the reduction in hospitalization without an increase in adverse events such as syncope suggests that this programming approach should be considered for adoption in the care of patients with ICDs and clinical characteristics similar to those enrolled in these studies."
Study author Gasparini noted that the research provides physicians with an easy programming guideline that's "applicable to the great majority of patients who may benefit from the reduction of unnecessary painful shocks and hospitalizations."