Monday, November 12, 2007 Dumaguing: Heart-ware: Keeping up with pacemakers and defibrillators By Dr. Vic Dumaguing To your health
WHEN Canadian researcher John Hopps invented the first cardiac pacemaker in 1950, no one could have predicted how quickly the devices would become integrated into the medical mainstream. His discovery that mild electrical shocks could restore normal heart rhythms led to an estimated 250,000 pacemaker implants each year. More sophisticated, implantable defibrillators to prevent tachycardia also have become an almost routine cardiac procedure. More than 2.2 million Americans are affected by irregular heart rhythms, but what are we learning about these devices and their impact on the lives of patients?
Heart patients may experience heightened anxiety and depression after insertion of an implantable cardioverter defibrillator (ICD), especially during their first year. Researchers will describe a special education and counseling program that significantly reduced clinical symptoms in this randomized trial involving 264 patients. Among them, 73 percent were men and 20 percent were African-American. The researchers divided the patients into two groups, one receiving usual post-implant follow-up care and another where patients were assigned to receive counseling and intervention during acute post-surgical care and again two or three months later, by telephone or in a group setting.
Patients received information on symptom management, cognitive behavioral techniques, coping skills and illness appraisal. The intervention resulted in increased use of active coping techniques and reduced threatening perceptions of the ICD. Although anxiety and depression scores declined in all of the patients over the course of the first year, depression scores in patients who did not receive intervention were more than twice as high as those among patients in the intervention program whose anxiety scores were also lower.
Wireless computer networks like Wi-Fi and Ethernet pose little danger for people with pacemakers and defibrillators, according to German researchers. With the dynamic evolution of wireless technology, there has been some concern about the potential effects of electromagnetic interference on heart pacemakers and implantable cardioverter defibrillators.
The Federal Communications Commission (FCC) limits the power generated by local area networks (LANs), but the agency allows power levels that are higher than those permitted in Europe. These scientists exposed 25 pacemakers and 22 defibrillators to the maximum U.S. and European WLAN (Wireless LAN or Wi-Fi) levels to see if they caused interference that might place patients at risk. Although interference occurred in 10.6 percent of the devices, there was no clinical significance. Five pacemakers showed mild interference in telemetry signals and WLAN radiation inhibited programming of emergency broadcast signals in one pacemaker model.
The scientists concluded that current wireless levels do not interfere with the devices, but because they can impede emergency programming and telemetry signals, hospitals should locate these services away from high-output access points.
