Pacemaker

Synonyms in a broader sense

Pacemaker, HSM,

English: pacemaker (PM)

Definition of pacemaker

A Pacemaker is an artificial clock for that heart. It is used in patients who have a heart that is beating too slowly (Bradycardia) or take frequent breaks. The device emits electrical impulses at regular intervals that stimulate the heart muscle, causing it to contract (contraction) stimulate.

Epidemiology

In 2007, more than 66,000 pacemakers were used in Germany. The average age at which a patient receives a pacemaker for the first time is currently (Status 2011) at 75 years.

history

In 1932, the New York doctor described "Hyman" for the first time a device that could electrically stimulate the heart through periodic current pulses. This invention consisted of a DC generator and a circuit breaker.
With the help of an inserted needle electrode, the device should then Heartbeat through the Rib cage stimulate through. This first pacemaker weighed a remarkable 7.2 kg and had to be recharged every 6 minutes.

The two doctors "Senning" and "Elmquist" implanted the first pacemaker system that was completely embedded in the human body on October 8, 1958 in Stockholm in the patient Arne Larsson. They opened the man's entire chest and sewed the electrodes directly onto the heart muscle.

The device used consisted of two transistors, a mercury battery cell and a coil that could be charged from the outside. However, the capacity of the battery was so low that the life of the pacemaker was only 24 hours after the operation. Larsson only died in 2002, after becoming the proud owner of 21 other pacemakers in the course of his life.

In Germany became the first Pacemaker 1961 by the doctor "Sycosh" transplanted at the University Hospital in Düsseldorf. The recipient was a young person who was in a life-threatening condition following a motorcycle accident. His chest was sawed open and an open heart surgery followed. The implanted Pacemaker included ten Zinc oxide batterieswhich together reached a total duration of 18 months.

The biggest challenges in the advancement of the pacemaker have been to extend battery life and try to invent a device that works in the natural Cardiovascula-Function could be integrated with. 1965 Then pacemakers emerged that really only stimulated the heart muscle when needed. From 1971 to 1976, cardiac pacemakers were used, also in West Germany, which generated their required electrical energy from the decay of around 200mg plutonium (a toxic, radioactive heavy metal).

Towards the end of the 1980s, the pacemaker was expanded to include movement and temperature probes, and in 1992 a pacemaker was used for the first time that could be fully integrated into the natural regulation of the cardiovascular system.

In 1995 the Dual chamber stimulation by means of an electrode.

To this day, attempts are still being made to optimize the pacemaker, especially with regard to its function and aftercare, even though considerable advances in technology have been made since the first device, especially with regard to service life and programmability.

Structure and functionality

Today's Pacemaker are about the size of a matchbox and weigh between 20 and 27g. They have a titanium case, a small electronic circuit with a pulse generator with a Lithium-iodine accumulator, a battery that gives the pacemaker an average life of 10 years.
One or two thin wires (Probes) connect the device to the Musculature of the auricle and / or ventricle. These are able to receive electrical impulses from both Heart away, as well as to lead to the heart. They are responsible for checking the activity of the heart and passing this information on to the pacemaker. This can then react if necessary by sending out electrical impulses.

The program can now be easily adapted to the individual needs of different patients. The implanted pacemakers are adjusted wirelessly, usually by means of an interrogation device that is placed on the wearer's chest.

Types

In principle there is three types of pacemakers:

The Unicameral pacemakerwhich has only one probe and electrically stimulates either ventricle or atrium, the Dual chamber pacemaker, which contains two probes and can thus successively deliver electrical impulses to the chamber and atrium, and thirdly the rate-adapted pacemaker, with one or two probes, whereby the pacemaker is able to adapt the frequency of the impulses to the current life processes.

The pacemakers are named with three letters after a certain one Coding system. The first letter indicates the stimulation location (A. For Atrium = Atrium or V For Ventricle = Chamber, D. For dual = A. and V), the second the registration location (i.e. the point at which the pacemaker records the heart action) and the third letter describes the operating mode of the pacemaker. A distinction is made here between an inhibiting (I.) and a triggered (T) Mode.

In the inhibiting mode, the suppresses Pacemaker its impulse, as soon as it records an activity of the heart, in triggered mode, a perceived signal triggers pacemaker activity. A D. for dual means that the pacemaker can run in both modes. If the fourth letter is still a R. follows, this means that the pacemaker has the ability to adapt the rate and a fifth digit can describe how many points stimuli are delivered (multifocal stimulation).

The most common type of pacemaker is the unicameral pacemaker VVI. As long as the heart works independently, it is inactive. It is mainly used to treat the Bradycardia used. Disadvantages of this type of pacemaker are, on the one hand, that it is not rate-adapted, i.e. cannot adapt to the currently required performance, and, on the other hand, that atria and ventricles may no longer work synchronously, which in the worst case can trigger a pacemaker syndrome.

In diseases of the sinus node, the AAI for use with the probe in the atrium.

Of the Type DDD is a two-chamber pacemaker which is used for conduction disorders from atria to ventricles, as it can stimulate atrium and ventricle one after the other, which mimics the natural heart activity.

Summary

A Pacemaker is used in patients whose heart, for very different reasons, is no longer able to independently maintain a sufficient pumping function that could supply the body with sufficient oxygen.

The Operation for a pacemaker is a routine procedure and has only a few complications. Apart from the check-ups that are required at regular intervals, those who wear a pacemaker can lead a normal everyday life and usually hardly feel the artificial clock in their body. The only thing to watch out for is that they are not near strong magnetic fields or Magnetic resonance tomograph may issue. Devices that represent a hazard must have a corresponding prohibition sign.