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Effects of electromagnetic radiation on pacemakers

The problems

The pacemaker electrode can act as an antenna. It captures disturbing electromagnetic signals and carries them into the pacemaker. Magnetic fields can also enter the housing directly. In both cases malfunctions of the pacemaker can be initiated.

Solution

The warning device Cardioman enables you to recognize disturbing signals and to leave the area of risk. Furthermore Cardioman allows a risk assessment for electrical everyday appliances. Cardioman alerts the user with visible and audible warnings.

Detailed information

Signals with low frequencies can directly intersperse magnetic fields into the pacemaker housing. Additionally the pacemaker electrode can act as an antenna that captures disturbing electromagnetic signals with higher frequencies and carry them into the pacemaker.

The exposure of a pacemaker to electromagnetic radiation can

• produce currents from the electrode into the cardium and therefore ventricular fibrillation or tissue damage by local heating
• induce electric voltage into the electrode that influences the pacemaker's control of heart signals (ECG)
• induce electric voltage into the electrode that damages the pacemaker
• accidentally activate or damage magnetic controllers of the pacemaker
• cause the pacemaker to switch into the safety mode

The draft standard DIN VDE 0848-3-1 is the basis

Hazards depend on the electrode's orientation but also on the properties of the electromagnetic field. The frequency and signal form (modulation type) of the field have a special impact. E.g. pacemakers respond exceptionally critical to modulation frequencies that are similar to the heart's own rhythm.

The draft standard DIN VDE 0848-3-1 ("Safety in electric, magnetic, and electromagnetic fields" dated May 2002) specifies typical thresholds at different frequencies for variably modulated fields. Since the thresholds depend on the circuitry of the device and vary for different devices the thresholds have been defined in that way, that more than 95% of all pacemakers being implanted in the time period between 1995 and 1999 are not affected at field strengths below the given values.

The draft standard recommends to mark all public areas where a hazard for pacemaker patients might occur with warning signs. However, the implementation of this measure has proved to be not practicable. It is for example almost impossible to provide all power transmission lines over kilometres with warning signs.

That is why the Cardioman follows another approach: It gives every patient the possibility to identify and avoid dangerous areas by himself or herself. It additionally enables to value the hazards of everyday electric appliances.

Guideline of the International Commission on Non-Ionizing Radiation Protection

The ICNIRP (International Commission on Non-Ionizing Radiation Protection) works out and regularly publishs guidelines for different radiation modes which are based on the accepted state of science and art. A respective guideline also exists for electric, magnetic, and electromagnetic fields (see ICNIRP guideline). It includes very interesting information about the interaction of such fields with the human body.

Product description

Cardioman - The warning device

• facilitates the valuation of everyday hazards
• warns of electromagnetic radiation ("electromagnetic pollution")
• signals the necessary distance to household appliances, broadcasting antennas, machines, transformers, etc.
• discovers damaged appliances with bad risk

Function

The Cardioman warns of magnetic and electromagnetic fields (EMF) that can cause interferences with pacemakers or defibrillators. Whenever the measured field strengths approach specific limits that can cause a hazard for the user it informs you by means of acoustic and visual signals. Important: The warning appears before an interference or disfunction can take place. Thus, you can avoid the source of danger before anything happens.

The Cardioman can be a continuous companion in everyday life. It points out possible dangers and provides more safety. It additionally enables the valuation of hazards of everyday household appliances or machines. In such a way you can discover and sort out damaged appliances with bad risk.

More safety

Certain guidelines with respect to electric appliances are communicated by the attending physician or in information material. However, an uncertainty due to residual risk remains with the pacemaker or defi patient. Here, the Cardioman provides additional safety. For the first time you have the possibility to check and prove these guidelines. You gain more freedom in the arrangement of your life. E.g. it is more convincing to straightly check the radiation of your mobile phone than to follow the recommendation not to position it close to your pacemaker. In most cases you will find out, that the devices you use do not bear any risk. Uncertainty is replaced by safety.

In occupational safety the warning system renders a good service by detecting the fields emanating from appliances and machines. The Cardioman supports the assessment of workplaces, helps to avoid accidents, and gives the pacemaker or defi patient more safety.

Technology: The Cardioman ...

• detects magnetic fields and electromagnetic radiation
• covers the complete frequency range from 0 to 3.3 GHz
• warns with acoustic and visual signals
• is consequently adjusted to the characteristics of pacemakers
• is likewise appropriate for defis / ICDs
• comprises six integrated antennas and four different detectors

Danger sources

Reasons for failures or interference

The public debate about electromagnetic pollution concerns whether or not the human body can be affected by electromagnetic radiation. The scientific position is still not clear. Anyhow, there are guidelines and directives that include limits for the electromagnetic compatibility of electric appliances.

In case of pacemaker or defi patients we have a different problem: Here, the body is not directly interacting with the electromagnetic radiation but indirectly via the implanted electronic device that is in addition equipped with an electrode acting as an antenna. In this case we have to consider not only biological but also and primarily physical effects.

In spite of increasing safety with respect to external radiation there still remain failure hazards even with modern pacemakers:

• External signals can be misinterpreted as signals from the heart. Then a necessary stimulation by the pacemaker can be suppressed although the heart does not have sufficient rhythm by its own.
• External fields can cause the pacemaker to switch into the safety mode with constant frequency that might be too low for the patient in the current situation.
• Disturbing signals can embarrass the pacemaker to detect the heart's own rhythm, thus misleading the adaption of the stimulation frequency to the variations of the external field. Moreover, it can be critical, if unwanted stimulation takes place in the vulnerable phase of the heart's rhythm.

In most situations no interference of the pacemaker will occur. However, in rare cases malfunctions can lead to light or severe heart rhythm disturbances. The patient recognizes this as dizziness, inefficiency, or even unconsciousness. And defi patients can experience unwanted shocks. If the patient is dependent on a permanent stimulation, the worst case is cardiac arrest.

The Cardioman helps ...

• to determine the minimum distance to dangerous appliances
• to prove the information given in appliances' instruction manuals
• discover damaged appliances with bad risk

More safety by early warnings

Thresholds for the exposure of pacemakers depend on the frequency of the disturbing field. In all ranges the Cardioman already alerts before the threshold is reached. This is illustrated by the advance warning area in the following chart. After that a number of appliances that can have interfering effects on pacemakers are listed.

Sources of danger

Examples of potential danger sources of electromagnetic radiation are anti-theft devices, broadcasting transmitters, loudspeaker magnets, and wireless or mobile phones / cellular phones. More examples are plotted in the chart above or can be found in the references of pacemaker suppliers. In almost any case the actual risk depends on the distance between the disturbing source and your pacemaker or defi. This phenomenon can be easily and directly watched with the Cardioman.