Jauchem, JR, · 1997
The review examined cardiovascular changes in humans exposed to extremely-low-frequency electromagnetic fields and radiofrequency radiation. Most studies showed no acute effect of ELF EMFs on blood pressure, heart rate, or electrocardiogram waveform, though some reported subtle heart rate effects. Soviet reports from the 1960s linked long-term ELF EMF exposure to arrhythmias and tachycardia in switchyard workers, but Western studies did not confirm this. MRI-related RFR exposures were concluded not likely to cause adverse cardiovascular effects. Overall, no obvious cardiovascular hazards were found for exposures below current standards.
Hayes DL et al. · 1997
Researchers conducted a multicenter, prospective, crossover study testing 980 patients with cardiac pacemakers using five types of cellular telephones. Telephones were tested at maximal power in a test mode and one telephone during actual transmission, with monitoring at the ear and over the pacemaker. The incidence of any interference was 20 percent in 5533 tests, clinically significant interference occurred in 6.6 percent, and definitely clinically significant interference occurred in 1.7 percent only when the telephone was held over the pacemaker. Interference was more frequent with dual-chamber pacemakers than with single-chamber pacemakers and more frequent with pacemakers lacking feed-through filters than with those having filters.
Gadzicka E, Bortkiewicz A, Zmyslony M, Palczynski C · 1997
The study used 24-hour blood pressure monitoring with a Medilog ABP kit to assess male workers from middlewave broadcast stations, radioservice stations, and radio line stations. Mean arterial blood pressure and day-night blood pressure variability did not differ significantly between exposed and control groups. Daily heart rate was significantly lower in middlewave broadcast station workers compared to controls despite similar work and non-occupational activities. Day-night heart rate variability was significantly lower in exposed groups, which may suggest neurovegetative regulation disorders. Radioservice station workers had a higher incidence of increased arterial blood pressure than controls.
Altamura G et al. · 1997
The study used continuous ECG monitoring of 200 pacemaker patients to determine whether digital and analogue cellular phones affect them. GSM phones caused 97 interference episodes in 43 patients (21.5%) and TACS phones caused 60 episodes in 35 patients (17.5%). Interference episodes were more frequent during ringing (131) than during the on/off phase (26), and more at maximum sensitivity (106) than at base value (51). Prolonged pacing inhibition over 4 seconds occurred in six patients with GSM at base sensing value but only one with TACS. The researchers concluded that cellular phones may be dangerous but can be used safely if not carried close to the pacemaker.
Bortkiewicz et al. · 1997
This study evaluated the circulatory system function of workers occupationally exposed to medium-frequency electromagnetic fields. The study included 71 workers at four AM broadcast stations operating at 0.738–1.503 MHz and 22 workers at radio link stations who had no history of regular electromagnetic-field exposure. ECG abnormalities were significantly more frequent in exposed workers than in non-exposed workers (75% versus 25%, p = 0.006), and a tendency for more rhythm disturbances was observed in AM broadcast station workers.
Fiorani M et al. · 1997
Researchers investigated the effects of 50 Hz magnetic fields (0.2–0.5 mT) on rabbit red blood cells exposed at the same time to an oxygen radical-generating system, Fe(II)/ascorbate. A 0.5 mT magnetic field had no effect on intact red blood cells, but when cells were already under oxidative stress, exposure caused a significant further decay in hexokinase activity of about 20% and a twofold increase in methemoglobin production. The researchers concluded that the magnetic fields studied were able to potentiate the cellular damage induced in vitro by oxidizing agents.
Sparks PB, Mond HG, Joyner KH, Wood MP · 1996
Researchers exposed 16 implanted Telectronics META pulse generators to simulated GSM transmissions and a 2-W digital mobile telephone. The devices were programmed to maximum sensitivity and tested in unipolar and bipolar settings and rate adaptive and nonrate adaptive modes. At maximum sensitivity, 11 of 16 devices showed no EMI, while brief ventricular triggering, pauses, and one episode of pacemaker-mediated tachycardia occurred in the remaining devices. When programmed to routine sensitivities, only one device displayed rare single beat ventricular triggering, and no changes in minute ventilation rate adaptive pacing were observed.
Nowak B et al. · 1996
Researchers evaluated 31 patients with three types of single lead VDD pacemakers for interference from a 2-W mobile phone in the digital D-net. Atrial and ventricular sensitivity were programmed to their most sensitive values and ventricular sensing to unipolar. The phone's extendable antenna was placed in direct skin contact at the right sternal border just below the clavicle, within 5 cm of the pacemaker connector, while ECG was continuously monitored. No interference was detected and programmed values remained unchanged after the test. The authors concluded the interference risk appears low but could not be entirely excluded due to study design.
Wilke A, Grimm W, Funck R, Maisch B, · 1996
Researchers tested 50 patients with permanent pacemakers using a D-net cellular phone (Ericsson, 890–915 MHz) during three pacemaker settings. A six-channel surface ECG was continuously recorded to detect interactions. Only 2 patients (4%) repeatedly showed intermittent pacemaker inhibition during calls, and both had unipolar sensing. The authors concluded that interactions appear rare but pacemaker-dependent patients should avoid cellular phone use.
Naegeli B, Osswald S, Deola M, Burkart F · 1996
Reproducible interference occurred in 7 of 39 patients during 26 of 672 tests with phones operating within 10 cm of the pacemaker. Ventricular inhibition was induced only in unipolar pacing mode (12.5% positive test results). Interference was more likely at higher phone power output and maximal pacemaker sensitivity (6% vs 1.8% positive tests).
Irnich W, Batz L, Muller R, Tobisch R · 1996
Hofgartner F, Muller T, Sigel H · 1996
Researchers tested 104 patients with 58 different pacemaker models using three mobile phones from the C and D networks. They varied the distance between the phone antenna and the pacemaker, and adjusted the pacemaker's sensitivity and polarity settings during continuous ECG monitoring. Interference occurred in 43 patients (41.3%) and 28 pacemaker types (48.3%), including inhibition, switching to interference frequencies, and triggering of tachycardias. The D-network portable phone caused interference more often and at greater distances than the D-network handy phone, which performed similarly to the C-network phone. Reducing pacemaker sensitivity and switching to bipolar reception only partly eliminated the interference.
Chen WH, Lau CP, Leung SK, Ho DS, Lee IS · 1996
Researchers tested 29 patients with permanent pacemakers using three cellular phones at three positions and eight pacing modes. Interference occurred in 74 of 2,418 episodes (3.1%) in eight patients, only when the phone was above the pacemaker pocket. Three interference types were seen: inhibition of pacing output, rapid ventricular tracking in DDD(R) or VDD(R) mode, and asynchronous pacing. Unipolar atrial leads were more susceptible than bipolar or ventricular leads. Reprogramming sensitivity prevented interference in all patients.
Bortkiewicz A, Gadzicka E, Zmyslony M, · 1996
The study compared 71 workers at medium-frequency broadcast stations with 22 non-exposed radio link station workers. Age and work tenure distributions did not differ significantly between groups. Heart rate variability was measured from 512 normal heart evolutions at rest using a Medea-HV system. Time-domain and frequency-domain HRV parameters showed no statistically significant differences between exposed and non-exposed groups. In the exposed group, maximum EM field intensity correlated negatively with high-frequency power spectrum.
Bortkiewicz A, Zmyslony M, Gadzicka E, Szymczak W · 1996
The study covered 71 workers at four AM broadcast stations, 40 workers at ten radio link stations, and 42 workers at three radioservices. Workers underwent subjective and objective medical examinations, resting electrocardiogram, Holter measurements, high intensity ECG, and long-term blood pressure recording for cardiac rhythm analysis. Exposure to EMF at AM broadcast stations increased the risk of electrographic disturbances six times in comparison with radio link station workers not exposed to medium wave EMF. Radioservice workers had twice the risk of electrographic disturbances compared to link station workers.
Barbaro V, Bartolini P, Donato A, Militello C · 1996
Researchers used a human trunk simulator and two TACS-standard analog cellular telephones to test pacemaker interference. The electromagnetic field from the telephones interfered with 10 of 25 pacemakers tested. Close proximity of the telephone antenna caused desensitizing, sensitizing, and pulse inhibition during incoming calls and ringing, with the worst case showing three skipped beats. Maximum sensing threshold variation reached about 186% increase and 62% decrease, and pulse inhibition also occurred during failed connections and cell crossing, though the latter did not appear to pose a risk under experimental conditions.
Wolke S, Neibig U, Elsner R, Gollnick F, Meyer R, · 1996
Pakhomov AG, Dubovick BV, Degtyariov IG, Pronkevich AN · 1995
Pakhomov AG, Dubovick BV, Degtyariov IG, Pronkevich AN · 1995
Researchers studied the combined effects of microwave radiation and drugs on an isolated frog auricle preparation. Exposure to pulse-modulated 915 MHz microwaves for up to 40 minutes had no effect on the rate or amplitude of spontaneous auricle twitches unless the absorbed power caused heating. Caffeine (1 mM) strongly increased the average heart power, and this effect was significantly augmented by about 15% under burst-type pulsed microwaves with an average SAR of 8-10 W/kg, while heating was only approximately 0.1°C.
Rittweger J, Lambertz M, Kluge W, Kramer K, Langhorst P · 1995
The study examined magnetoencephalogram, heart frequency and ventilatory parameters before and after occipital application of the fields. Differences in these measures indicated that the effects can be explained by an influence on the common brainstem system.
Yoshida Y et al. · 1995
Researchers exposed pregnant rats to whole-body microwaves at 10 mW/cm2 and 2,450 MHz and measured placental blood flow and five endocrine indicators. Placental blood flow at 45-90 minutes after exposure was significantly decreased in exposed rats. Microwave exposure increased corticosterone and decreased estradiol regardless of angiotensin II pretreatment, increased progesterone and prostaglandin F2 alpha without pretreatment, and did not change prostaglandin E2. Pretreatment with angiotensin II increased placental blood flow at 15 and 30 minutes, but this effect was absent in microwave-exposed rats.
Yee KC, Chou CK, Guy AW · 1994
Researchers investigated the effect of microwave exposure on conduction velocity of frog ventricular muscle. Thirty-two frog hearts were divided into four groups and placed in temperature-controlled waveguides with Ringer's solution. One group served as control while three groups were exposed for 2 hours to pulsed 2,450 MHz microwave fields at SARs of 0.003, 2, and 6 W/kg. No significant difference in conduction velocity was found between control and exposed groups.
Vergassola R et al. · 1994
Researchers studied the effects of various electromagnetic sources including short-wave diathermy, electrosurgical knives, electrotherapy, and radiofrequencies on both humans and animals. Short-wave diathermy was tested with various electrode positions in pigs and 8 patients with pacemakers. Electrosurgical knives were tested on pigs with unipolar knives, on 6 humans during automatic defibrillator implantation using two-pole knives, and on 23 pacemaker patients undergoing abdominal surgery using two-pole knives. Electrotherapy (TENS) and radiofrequency ablation were tested on pigs. The results were completely negative, leading the researchers to conclude that modern pacemakers are more reliable and less susceptible to electromagnetic interference.
Lu Y, Yu J, Ren Y · 1994
Researchers measured dielectric properties of human red blood cells in suspension at 25 degrees C across 1-500 MHz using a coaxial transmission line reflection method. The study included 243 healthy persons with a hematocrit of 50%. The data revealed a statistically significant age dependence with a critical age of about 49 years, above which permittivity and conductivity decreased significantly.
Zhao Z, Zhang S, Zho H, Zhang S, Su J, Li L, · 1994
Researchers examined 121 workers exposed to radiofrequency radiation below 30 MHz for over one year, divided into high-intensity (>=100 V/m) and low-intensity (<100 V/m) groups compared to controls. No significant changes in autonomic nervous system functioning or blood parameters (hemoglobin, white blood cells, platelets) occurred in either exposed group. However, ECG changes including ST-T interval alterations and abnormal heart rate were observed in the high-intensity exposure group. The authors suggested 100 V/m as an exposure limit for radiofrequency radiation below 30 MHz.
