Pacemaker

Single chamber pacemaker from Guidant (explanted after regular battery exhaustion). Photo from 2005

Single-chamber pacemaker (VVI) on an X-ray

A pacemaker ( HSM ) or Pace Maker ( PM ) ( English for, pacemaker ') is an electronic pulse generator for the (mostly regular) electrical stimulation (stimulation) of the heart muscle for contraction . The device is used to treat patients with slow heartbeats ( bradycardiac arrhythmias ).

Strictly speaking, the heart's natural clock generators, the sinus nodes and possibly the atrioventricular nodes , are "natural pacemakers"; but the term is used predominantly for the artificial. In 2009, more than 730,000 new pacemakers were implanted worldwide.

history

First non-implanted pacemaker

In the 1950s, the first non-implantable cardiac pacemakers were designed, including in 1951 by the Canadian Wilfred Gordon Bigelow and in 1952 by the American Paul Maurice Zoll .

First implantations

Wearable pacemakers were developed in 1957 by Earl Bakken , founder of Medtronic .

First implantable pacemaker

The first pacemaker completely embedded in the human body was implanted on October 8, 1958 by the doctor Åke Senning and the engineer from Siemens Elema , Rune Elmqvist , in the patient Arne Larsson in Stockholm . Curiously, neither of them believed in the long-term success of pacemakers at the time. The device consisted of two transistors that worked in a flip-flop circuit, a nickel-cadmium accumulator and a coil for external charging of this accumulator . The capacity of the accumulator was already exhausted after a short period of time. The electronic components were encapsulated in a shoe polish can with epoxy resin. The electrodes required to deliver the stimulation energy to the heart were firmly attached to the pacemaker.

In Germany, Heinz-Joachim Sykosch (1926–2017) implanted the first 300 gram Medtronic CHARDACK-GREATBATCH 5850 cardiac pacemaker on October 6, 1961 at the Düsseldorf University Hospital , against the express will of his superior at the time. The recipient was 19-year-old Hans Gerd Finkentey († 1987), who was in mortal danger after a motorcycle accident. At that time, the operation was carried out on an open heart, the chest cavity had to be sawed open. The pacemaker was equipped with ten zinc oxide batteries with a total running time of approximately 18 months. In Austria, the first pacemaker was used in 1963 at the General Hospital of the City of Vienna (AKH) .

Radionuclide batteries

Plutonium pacemaker

Medtronic Laurens Alcatel model plutonium pacemaker

Since these first pacemakers only had a short battery life, pacemakers with radionuclide batteries were then implanted, which gained the required electrical energy from the decay heat of about 200 milligrams of plutonium ²³⁸ Pu. These pacemakers were also implanted in patients in West Germany between 1971 and 1976. Some are still in use today. Plutonium pacemakers were implanted in the Soviet Union until the mid-1980s.

The main advantages for the patients were that, thanks to the long service life of the batteries, no electrodes had to be passed through the skin to the outside. This eliminated wound care. In addition, the psychologically stressful charging cycles were eliminated.

The plutonium-containing pacemakers implanted in Germany were also recorded in a register of the Federal Office for Radiation Protection (BfS). In 2014 there were still two people who were still alive who had been implanted with pacemakers with plutonium-238 in 1972 and who still had them.

In an investigation, the BfS is discussing the radiation exposure of the wearer and the environmental impact of improper disposal of the unit.

Promethium pacemaker

The by the company Biotronik pacemakers produced in 1970 used by the beta decay of naturally occurring promethium - nuclide ¹⁴⁷ Pm emitted electrons to generate electricity ( Betavoltaikbatterie ) and at least reached a theoretical term of 10 years, with lower material prices and lower risk potential compared to plutonium.

The requirements for promethium pacemakers are less stringent than for plutonium pacemakers.

Pacemaker removal scandal 1976–1979

From 1976 onwards, the public prosecutor's offices in Cologne and Frankfurt am Main received anonymous reports, according to which there were specific suspicions that pacemakers were illegally removed from corpses, overhauled and used again for heart patients. The patients were not informed of this. On February 11, 1977, the Association of Leading Hospital Doctors in Germany "emphatically" advised its members against collecting money from medical technology companies for reusing old pacemakers. The medical technology company Ernst-Günter Lehmann, Elektro-Medizinische Apparate GmbH in Rösrath near Cologne, became known through investigations , which demonstrably acquired the pacemakers of deceased patients from doctors for a "fee" of up to DM 2600  each and the used devices again at the new price had sold. Most of them were pacemakers from the Dutch company Vitatron . For example, a senior physician in Karlsruhe received exactly DM 2,971.29 from the company Ernst-Günter Lehmann, Elektro-Medizinische Apparate GmbH, for 46 Vitatron brand pacemakers that he had implanted between July 1, 1976 and December 31, 1976. Heart specialists such as Heinz-Joachim Sykosch, who was also the president of the “Society for Pacemakers e. V. ”, saw“ no medical concerns ”against the removal and reuse of impulse generators, but without any“ profiteering ”. According to the doctor, “such expensive devices” should “not simply be thrown in the garbage or given into the grave.” The Barmer Substitute Fund also did not consider the removal and re-use of the pacemaker to be legally controversial, since it does not involve the removal and transplantation of Organs of the body were comparable to a serious procedure, such as an autopsy. The health insurances saw the pacemaker in deceased patients as their property again and demanded notifications from the doctors about withdrawals so that the costs for the pacemaker would not be billed again. In other European countries and in the USA there were already legal regulations for the reuse of pacemakers in the 1970s, where there was a ban on the reuse of used pacemakers. Until 1979 the public prosecutor's office in Cologne investigated doctors and assistants, nurses and nurses in municipal and church clinics, in district and university hospitals, in private institutions and in those of the Red Cross. Including the district hospital in Wolfach , the Elisabeth hospital in Kassel, the clinic of the Hannover Medical School and the Trinity Hospital in Lippstadt. Most of the medics accused from the investigation paid fines between DM 2000 and DM 25,000 according to § 153 StPO because of “minor guilt of the perpetrator”. Around 400,000 DM in fines went to non-profit organizations. Today, the removal of a pacemaker without the consent of the deceased or his relatives is punishable under Section 168 of the Criminal Code for disturbing the peace of the dead . The explantation of dead that a cremation are fed - formerly legally due to the battery law (before 2009: the battery regulation ) prescribed - is no longer required for most modern crematoria.

function

Newer pacemakers also have other areas of application:

• Record cardiac arrhythmias in the patient (Holter functions)
• Bridge conduction disturbance between atrium and ventricle ( AV block ) (triggered stimulation)
• In the case of left bundle branch block and reduced ventricular function, improve the pumping function of the heart through bi- or left ventricular stimulation (cardiac resynchronization therapy - CRT)
• Adapt the beat sequence to the patient's physical activity (rate-adaptive pacemaker)
• Helping to avoid atrial arrhythmias (e.g. atrial fibrillation ), among other things through timely stimulation ( preventive pacing )

The functions of a pacemaker are also integrated in implantable defibrillators (ICDs) , since after electroshock therapy the cardiac actions are often too slow or only start again after a certain pause, as well as for patients who also need anti-bradycardia stimulation by a pacemaker anyway. This combination avoids the implantation of a second device and the problematic coordination of two devices.

After years of technical improvement, cardiac pacemakers are now safe and well-functioning systems that have made the chronic drug treatment of slow cardiac arrhythmias practically superfluous. The average age of the patients at the first implantation is 75 years.

The device, often incorrectly referred to as a “battery” in the vernacular, consists of a lithium-iodine battery or lithium-carbon monofluoride battery for the energy supply and the electronics for controlling the functions. Both are housed in a common housing. A modern pacemaker lasts between five and twelve years, with an average of eight years. In individual cases, a service life of over 19 years was achieved. If the reliable function is no longer guaranteed, a device change is carried out in a minor surgical procedure. Thanks to standardized electrode connectors (IS-1 standard), replacement is no longer time-consuming.

construction

implanted pacemaker

Pacemaker with an electrode

A pacemaker consists of the pulse generator (battery-operated device, device) and the electrode ( probe ) that connects the pulse generator to the chamber. The electrode conducts electrical impulses to the heart and signals from the heart back to the pulse generator. This controls the performance of the pacemaker.

Unit and drive

The main component (the aggregate) of a permanent (firmly implanted) pacemaker contains the battery, the pulse generator and the control electronics. Today only lithium-iodine batteries are used. Lithium-iodine batteries are solid-state batteries without liquid components, which are intrinsically safe and, due to their principle, cannot “leak” and show only a very low self-discharge .

The first permanent pacemakers used rechargeable batteries that had to be charged externally after a few hours of operation. Later, non-rechargeable mercury oxide-zinc batteries were used, which lasted a few months to three years and were difficult to hermetically seal because of the electrolyte . Radioisotope generators containing plutonium were installed for a short time . Soon afterwards, the lithium-iodine batteries finally prevailed.

electrode

The pacemaker electrode or probe connects the heart to the pacemaker. A probe consists of a connector, the electrode conductor and the electrode tip. The electrode head represents the final link between the pacemaker system and the heart. Its structure and attachment to the myocardium are therefore responsible for the optimal function of the electrode. The electrode head can be attached to the heart muscle using various fixation methods. The anchoring of the electrode can be divided into passive and active fixation mechanisms. The active fixation methods include the screw electrode , which is actively screwed into the myocardium. With passive fixation, such as the anchor electrode , the barb-like system is anchored in the trabecular network (the highly articulated surface of the right ventricle). Nowadays, actively and passively fixed probes are usually guided transvenously to the right heart. Both types of electrodes are placed with a special wire, a so-called mandrin, which is inserted into the lumen of the pacemaker electrode and removed again after implantation. An electrode inserted endocardially in this way stimulates the inside of the heart.

Depending on the design of the pacemaker electrode, a further distinction is made between:

• unipolar
• bipolar
• straight
• pre-bent
• VDD electrodes

Programming unit

In the case of implanted pacemakers, the setting is carried out wirelessly and bidirectionally, usually by means of an interrogation device placed on the chest, and contactless radio transmission is also used. External pacemakers are set directly on the device.

functionality

Cardiac pacemakers are connected to electrodes that are used both to perceive the cardiac function and to stimulate it. An EKG is recorded and evaluated using these electrodes . Depending on the purpose and structure, different signals from the EKG are used as triggers . The QRS complex from the ECG is often used as a trigger to detect the heartbeat. If no heartbeat is detected within an adjustable period of time, stimulation with an electrical impulse follows.

Possible complications

• Failure of stimulation
• Heart muscle injury (myocardial perforation)
• Cardiac arrhythmias (atrial fibrillation, ventricular fibrillation)
• Esophageal injury from transesophageal stimulation
• Thrombophlebitis with intracardiac stimulation
• Knot and lead dislocation during intracardiac stimulation

Types

There are different types of pacemakers, which can be divided into five types according to the location of the stimulation, for example:

• Transcutaneous stimulation (external, non-invasive pacemaker): Large, stick-on electrodes are used to deliver a current through the skin, whichstimulatesthe heart . Due to the large distance between the electrodes and the heart, large currents are necessary, which lead to an undesirable stimulation of the skeletal muscles. Therefore, this procedure is only useful and practicable in an emergency and the patient should beshieldedwith analgesic sedation .
• Esophageal stimulation : This is a minimally invasive procedure in which an electrode ispushedthrough the esophagus up to the level of the heart. The stimulation is painful and is therefore rarely carried out, mainly for diagnostic purposes (the atrial location enables better differentiation of atrial and ventricular action). The process was not widely used.
• Temporary intracardiac stimulation : it will have a larger vein ( basilic vein , jugular , subclavian or innominate vein introduced) a pacemaker probe (with chamber electrode or atrial electrode) in the right half of the heart, in open heart surgery, the electrode is attached directly to the heart. The pulse is generated by an external stimulator. Because of the increased risk of infection and the risk of endocarditis compared to other types, this method is only suitable for temporary therapy.
• (Temporary) extracardiac stimulation : In the early days of pacemaker therapy, the electrode was sewn directly onto the heart. Today, temporary stimulation from the outside of the heart is only given after cardiac surgery. The electrode cables are led out through the skin at the lower end of the sternum .
• Intracardiac stimulation by implant : The pacemaker is implanted above the right or left breast below the collarbone, mostly under the skin (subcutaneous) or, in lean patients, under the large pectoral muscle (submuscular). The electrodes are passed transvenously to the right atrium or right ventricle (with the biventricular pacemaker, a third electrode is advanced through the right atrium and the coronary vein sinus to the posterolateral wall of the left ventricle). This type of pacemaker implantation is the most commonly used in practice.

Types of permanent pacemakers

Revised NASPE / BPEG code
Job	1.	2.	3.	4th	5.
meaning	Stimulation location	Registration location	Operating mode	Frequency adaptation	Multifocal stimulation
content	0 (none)	0 (none)	0 (none)	0 (none)	0 (none)
	A (atrium)	A (atrium)	T (triggered)	R (adaptive)	A (atrium)
	V (ventricle)	V (ventricle)	I (inhibited)		V (ventricle)
	D (Dual A + V)	D (Dual A + V)	D (Dual T + I)		D (Dual A + V)
	S (single A / V)	S (single A / V)

NBG pacemaker code

The pacemakers offered today follow the NBG code that has been in effect since 1988 and revised in 2002 and can be divided into several groups, which are abbreviated / designated with a maximum of five (usually only the first three) letters.

The first letter indicates the stimulation location: The letters are based on the position of the electrodes or the stimulation. "A" for stimulation in the atrium (atrium), "V" (formerly "B") stands for stimulation in the ventricle (heart chamber), "D" (dual) for stimulation in the atrium and chamber. "S" (English single ) stands for single-chamber stimulation if the pacemaker has not yet been implanted and is therefore not yet fixed to the atrium or ventricle. “0” stands for “no stimulation”.

The second letter indicates the detection location: Here, "A" for detection in the atrium, "V" for detection in the ventricle, "D" (dual) for detection in both heart areas, "S" ( single ) for single-chamber detection and " 0 ”used for“ no detection ”(with asynchronous stimulation).

The third letter indicates the mode of operation of the pacemaker. A distinction is made between "I" (Inhibition; English inhibited , " hemmer ") and "T" (Triggering; English triggered , "triggered"): In the inhibited mode, the delivery of an impulse is suppressed during intrinsic activity, in the triggered mode an im Atrium registered signal for impulse delivery in the ventricle. "D" (dual) means here again that both modes are supported, i. That is, in the case of a pulse in the atrium or ventricle, the corresponding stimulations are inhibited and, if there is an AV block, the stimulation in the ventricle is triggered (triggered) by an action registered in the atrium. “0” means that neither mode is supported. The designation "R" (reserve) describes the activation by a high, but not by a too low heart rate.

The fourth letter describes the programmability , telemetry and rate adaptation . “0” means that the pacemaker is not programmable. "P" (English programmable , "programmable") are pacemakers that allow a maximum of two functions to be programmed, and "M" (English multi programmable , "multiple programmable") those of more than two functions. "C" (English Communication , "communication") indicates the possibility of data telemetry and "R" (English rate modulation , " rate modulation ") the possibility of adapting the pacemaker frequency to a load-induced signal. Since the revision of the NBG pacemaker code in 2002, “P”, “M” and “C” can no longer be used officially, especially since these functions have become a matter of course for every modern pacemaker.

The fifth and last letter indicates the location of the multisite stimulation (multi-site stimulation). “A” means pacing in more than one location in the right atrium (or pacing in the right and left atrium). “V” stands for pacing at more than one point in the right ventricle or biventricular pacing (pacing in the right and left ventricles). “D” stands for multisite pacing in the atrium and ventricle. “0” means no multisite pacing, neither in the atrium nor in the ventricle. Before the revision of the pacemaker code in 2002, the fifth letter indicated the anti- tachycardia function. "0" means no antitachycardia function, "P" (English pacing , "clocking") antitachycardia stimulation, "S" (shock) and "D" (dual) pacing and shock. Occasionally, this outdated nomenclature is still used.

Unicameral pacemaker

V00 / A00

The pacemaker mode V00 / A00 is no longer used today, but only used as an emergency solution in the event of dysfunction in another mode. The pacemaker stimulates either the atrium or the ventricle at a fixed rate (asynchronous) and without any detection. The disadvantages are:

• Stimulation in the vulnerable phase (of the atrium / ventricle) is possible (risk of dangerous cardiac arrhythmias ).
• The lack of synchronicity between atrium and ventricle can lead to pacemaker syndrome in V00 .
• The stimulation regardless of any natural cardiac activity is poor from an energetic point of view and reduces the life of the implant.
• It is not possible to adapt to the required power (frequency adaptation).
• Parasystoles are possible.

When a magnet is applied , the pacemaker temporarily switches for control purposes in the V00 / A00- (or with dual chamber pacemakers, D00-) mode.

VVI

The VVI ventricular pacemaker remains one of the most common types of pacemakers. This pacemaker is used as an on-demand pacemaker: If the ventricular activity fails temporarily or completely, a pulse is emitted via the electrode into the ventricle after a set stimulation interval has elapsed. If there is sufficient ventricular activity, the pacemaker is not active (inhibited). This type of pacemaker is indicated for chronic atrial fibrillation with bradycardic (slow) conduction. Even in the case of intermittent AV block with mostly normal, intrinsic conduction and only seldom need for stimulation in the ventricle, this mode does not seem to be of disadvantage for the patient, if a relatively low lower rate and also a rate hysteresis are programmed. In this way, the hemodynamically unfavorable, asynchronous ventricular stimulation can be reduced to a minimum. The disadvantages are:

• The lack of synchronicity between atrium and ventricle can lead to pacemaker syndrome.
• It is not possible to adapt to the required power (frequency adaptation).

AAI

The atrial pacemaker AAI (related to atrial stimulation and detection, AA, as well as inhibition, I), also called atrial demand pacemaker, is the counterpart at the atrial level. It is a so-called physiological pacemaker because in sinus node syndrome it simulates the lack of excitation and allows the conduction of excitation to go the natural way. It is therefore only indicated in cases in which the excitation conduction system is fully functional and there is undisturbed atrioventricular conduction. In the pure sinus node syndrome it is the ideal stimulation mode. Due to the fact that some patients with sinus node syndrome also develop an AV block in the course of the course, this pacemaker mode is no longer common today.

SSI

Single-chamber pacemakers are also referred to as SSI on the packaging or in the specification, with the “S” standing for single , ie a single-chamber device. This takes account of the fact that the pacemaker can be used both in the atrium and in the ventricle.

Dual chamber pacemaker

(VAT)

The VAT pacemaker was the first two-chamber pacemaker that was able to ensure synchronization between the atrium and ventricle in the event of atrioventricular blockage, thus solving the hitherto unsolved problem of the so-called pacemaker syndrome. It detects impulses in the atrium and then stimulates the ventricle accordingly. Unfortunately he is “blind” to his own actions in the ventricle. There are currently no more implantable VAT pacemakers on the market.

The disadvantages are:

• Due to the lack of registration in the ventricle, pacing is possible in the vulnerable phase of the ventricle (risk of dangerous arrhythmias).
• The stimulation regardless of any natural cardiac activity is poor from an energetic point of view and reduces the life of the implant.
• Constant self- triggering is possible ( pacemaker-induced tachycardia ).

(DVI)

The DVI pacemaker can be used for sinus bradycardia and conduction disorders and was the first available pacemaker of its kind. It always emits an atrial pulse and then tests whether ventricular excitation occurs. If this is not the case, a pulse is emitted in the ventricle after an adjustable period of time. Pure DVI pacemakers are no longer on the market today.

The disadvantages are:

• Stimulation in the vulnerable phase of the atrium is possible (risk of atrial arrhythmias).
• The lack of synchronicity between atrium and ventricle with intrinsic activity in the atrium and additional AV blockage can lead to pacemaker syndrome.
• It is not possible to adapt to the required power (frequency adaptation).

VDD

The VDD pacemaker is a special form of the two-chamber pacemaker. It can only detect in the atrium, but not stimulate, and is therefore only indicated for AV block with retained atrial activity. He only needs one electrode with the tip in the right ventricle, which picks up the atrial signals via two freely floating electrode rings on the electrode at the level of the atrium. The restriction to one electrode simplifies and shortens the implantation.

The disadvantages are:

• If the atrial rate is lower than the base rate or there is no activity at all, the atrium works functionally in the VVI mode and then has the same disadvantages as a VVI pacemaker.
• The atrial signals are often only perceived with a small amplitude because the electrode in the atrium is not in direct contact with the myocardium.

DDD

The DDD pacemaker is a combination of the pacemaker types VVI, AAI and VAT and comes closest to the physiological function of the heart. The pacemaker stimulates in the atrium if no self-action has been perceived there after the set time interval. If no action is perceived in the ventricle after the set AV interval after a paced or detected atrial action, the pacemaker emits an impulse there. Cardiac activity in the atrium or ventricle leads, as in the case of single-chamber pacemakers, to the suppression of impulses in the respective chamber (inhibition). Furthermore, the DDD pacemaker can transmit detected atrial actions to the ventricle (triggered). This is the principle behind the atrioventricular block ( AV block ) and is called the VAT functional mode.

Three-chamber pacemaker (biventricular pacemaker)

Three-chamber pacemaker for cardiac resynchronization therapy, here without an implanted defibrillator (picture with annotations)

Cardiac resynchronization therapy (engl. CRT) is advised for asynchronous, cardiac contraction flow, usually in the context of a left bundle branch block , and at the same time highly reduced pump function with symptomatic course, that is, a restricted cardiac capacity of the severity II, III or IV according to NYHA classification with leads himself. An improvement in cardiac pumping function, physical resilience, quality of life and survival, especially in combination with a function as an implantable cardioverter defibrillator , could be demonstrated. For this purpose, a third electrode is introduced venously over the coronary sinus at the level of the side wall (posterolateral) of the left ventricle. In the left bundle branch block, the ventricular septum contracts first and the posterolateral region is delayed, which leads to inefficient pendulum flow within the ventricle and can significantly contribute to a reduced ejection rate. Due to the premature stimulation of the delayed excited posterolateral wall, the disturbed ventricular contraction process can be resynchronized.

Additional functions (rate adaptive pacemaker)

Each type of pacemaker can be equipped with a sensor that tries in various ways to adapt the stimulation frequency to current needs. The heart rate should increase during physical exertion. Many different principles are in use. The most common type of sensor is the "shake sensor" that reacts to vibrations ( piezoelectric crystal , accelerometer), further there including the QT sensor, the minute ventilation sensor and some others. There are now also pacemakers that have 2 sensors in order to combine the advantages of the individual principles and to mitigate disadvantages (two-sensor pacemakers) e.g. B. Boston Scientific Altrua. Closed-loop stimulation (CLS) has proven to be quite physiological. With this type of frequency adjustment, not only is there a reaction to physical stress, but a frequency adjustment is also carried out in the event of mental stress. Older, mostly physically less active patients in particular benefit from CLS. However, the CLS algorithm has the disadvantage that right ventricular stimulation is required.

Temporary pacemakers

Temporary pacemakers are also used prophylactically or therapeutically. Like other pacemaker types, they also differ in the placement of the stimulation electrodes:

• External transthoracic stimulation
• Transesophageal stimulation
• Transgastric stimulation
• Intracardiac stimulation.

Main settings of the temporary pacemaker:

• Frequency: approx. 20 / min for prophylactic indications ( “on demand” ), 70–90 / min for pacemaker dependency
• Sensing threshold (sensitivity): 0–6 mV
• Pacing threshold: below 1.5 mA to 15 mA

Temporary pacemakers are suitable, among other things, for low-risk antitachycardia pacemaker therapy that can be carried out without anesthesia using high-frequency stimulation ( overdrive stimulation with transvenous stimulation of the right atrium or right ventricle) as an alternative to medical or electrical cardioversion.

Prophylactic uses :

• Heart attack with high-grade AV blocks
• New emergent bifascicular block
• Alternating right and left thigh blocks
• Right or left bundle branch block with first-degree AV block.

Safety instructions for people with pacemakers

Prohibition sign P007 according to DIN EN ISO 7010 : No access for people with pacemakers or implanted defibrillators

In rare exceptional cases, electromagnetic fields emitted by some devices can temporarily interfere with the pacemaker. Signs of a possible disorder may include dizziness , palpitations, or an irregular pulse. As soon as the wearer has switched off the corresponding device or has moved away from the source of interference, a pacemaker works normally again. It is recommended that you quickly cross existing anti-theft systems (for example behind the cash registers and at the entrance and exit) and not stop in the area. Electrical devices should also be kept at least 15 to 20 cm away from a pacemaker, for example hair dryers, razors, soldering irons, cell phones, two-way radios, drills, table saws, loudspeaker systems, heating pads, remote controls, magnets. However, it will expire at larger magnets (for example, in magnetic mats for back pain or even permanent magnet - Undulators rarely to disturbances). With induction cookers , it is recommended to keep the pacemaker at least 40 cm away.

Until now, the rule has been that pacemaker wearers should generally avoid magnetic resonance imaging (MRI) , as these devices generate strong, changing magnetic fields. This can lead to overheating of the electrodes with an increase in the stimulation threshold, incorrect stimulation, possibly triggering dangerous rhythm disturbances and destruction of the device. MRI-compatible pacemakers have been on the market since 2011.

X-rays, even in the context of computed tomography , are harmless.

When using mobile phones , the Federal Office for Radiation Protection recommends a minimum distance of 20 cm from the implanted pacemaker. Cordless phones are considered harmless.

People with the necessary knowledge are theoretically able to manipulate cardiac pacemakers and automatic defibrillators ( ICD ) in a targeted manner and thus, for example, to carry out attacks on implant carriers. US computer experts from Boston pointed this out in an experimental study.

Magnet mode

Pacemaker magnet for implanted cardiac pacemakers, a ballpoint pen for size comparison.

The pacemaker's magnet function is an emergency mode . If there are errors in the registration of the heart's own actions or other complications, a permanent magnet can be placed on the patient's pacemaker. However, this should only be done with ECG monitoring, as the magnetic pad results in asynchronous stimulation (S00 for single-chamber systems or D00 mode for two-chamber systems). The heart's own actions are then ignored (including all possible interfering signals, of course ), but theoretically it is also possible to stimulate the device in the so-called vulnerable phase of the heart (the so-called spike-on-T phenomenon), which can trigger life-threatening ventricular fibrillation. In magnet mode, pacemakers excite the heart at a fixed rate of 60 to 100 beats per minute (depending on the model and company, e.g. newer Medtronic 85 bpm, Guidant 100 bpm, St. Jude 98 bpm, Biotronik 90 bpm, several models with the programmed basic rate) and ignore them all the heart's own actions. Furthermore, the magnetic frequency represents a (albeit imprecise) marker of the battery charge still present in the unit, so that a change in the magnetic frequency can indicate impending battery exhaustion. Exact information on the magnetic frequency and its statement can be found in the instructions for use for the doctor by the manufacturer for the individual implants, for example in collected form in documents such as the cardiac pacemaker type index , which summarizes the technical data of the known pacemakers, implantable defibrillators and some other cardiac devices Contains implantable electrical devices. The magnetic function of an implantable defibrillator, on the other hand, is usually in the fact that the therapies directed against rapid rhythm disturbances coming from the heart chamber are switched off by means of a magnet. This is useful in operations, for example, when there is a risk of incorrect registrations due to the "electric knife", or to prevent inadequate shock delivery in the event of a malfunction of the defibrillator. This function is usually programmable and can also be switched off permanently in individual cases (currently recommended for some models from Guidant, since in rare cases "hanging magnetic switches" after magnetic application could have led to permanent suppression of the life-saving shock delivery in the event of ventricular fibrillation) .

Manufacturer

Major manufacturers of pacemakers are:

• Abbott Laboratories (through the takeover of St. Jude Medical in 2017 , which in turn was formerly with Teletronics , in 1994 the takeover of Siemens-Pacesetter )
• Biotronics
• Boston Scientific (took over Guidant ; Guidant himself previously took over Sulzer-Intermedics and CPI; Cardiac Pacemakers Inc. )
• LivaNova (including former ELA Medical and Sorin Biomedica )
• Medtronic (including Vitatron )
• Osypka Medical (external pacemaker)

Market shares in Germany

According to the German Pacemaker Register, of the 77,188 implantations registered in Germany in 2016, the pacemakers came from the following manufacturers:

Number of HSM	Market shares in%	Manufacturer
29,412	38.1%	Medtronic with Vitatron
24,689	32.0%	Biotronics
18,079	23.4%	St. Jude Medical (with Abbott Laboratories since 2017 )
3,363	4.4%	Boston Scientific with CPI (Cardiac Pacemakers Inc.) / Guidant and Intermedics
1,560	2.0%	LivaNova (formerly Sorin Biomedica and ELA Medical)
85	0.1%	Other and unknown (Osypka, Cook, Implantronik, Medico, CCS, Cardiac Impulse, Stöckert)

See also

• Bladder pacemaker
• Intestinal pacemaker
• Brain pacemaker
• Diaphragmatic pacemaker

literature

• Susanne Hahn: pacemaker. In: Werner E. Gerabek , Bernhard D. Haage, Gundolf Keil , Wolfgang Wegner (eds.): Enzyklopädie Medizingeschichte. De Gruyter, Berlin / New York 2005, ISBN 3-11-015714-4 , p. 585.

Web links

Commons : Pacemaker  - Collection of images, videos and audio files

Wiktionary: Pacemaker  - explanations of meanings, word origins, synonyms, translations

• German pacemaker register , joint initiative of the German Society for Cardiology, Cardiovascular Research and AQUA - Institute for Applied Quality Promotion and Research in Health Care GmbH
• museum-digital: owl: Historical pacemakers and accessories

Individual evidence

1. ^ Harry G. Mond: The 11th World Survey of Cardiac Pacing and Implantable Cardioverter-Defibrillators: Calendar Year 2009-A World Society of Arrhythmia's Project . In: Pacing and Clinical Electrophysiology . tape 34 , no. 8 , 2011, p. 1013-1027 , doi : 10.1111 / j.1540-8159.2011.03150.x .
2. ↑ Berit Larsson, Håkan Elmquist, Lars Rydén, Hans Schüller: Lessons From the First Patient with an Implanted Pacemaker: 1958-2001 . In: Pacing and Clinical Electrophysiology . tape 26 , 1p1, 2003, p. 114-124 , doi : 10.1046 / j.1460-9592.2003.00162.x .
3. ^ NM van Hemel, EE van der Wall: 8 October 1958, D Day for the implantable pacemaker . In: Netherlands Heart Journal . tape 16 , no. 1 , 2008, p. 1-2 , doi : 10.1007 / BF03086195 .
4. ↑ Biography of Arne Larsson. ( Memento from December 10, 2011 in the Internet Archive )
5. ↑ Berndt Luederitz: History of the Disorders of Cardiac Rhythm. 3. Edition. John Wiley & Sons, 2002, ISBN 0-87993-705-X , p. 127. Limited preview in Google Book Search
6. ↑ E. Berendsen: Cardiologist Heinz-Joachim Sykosch - "Two holes in the heart - done". In: Frankfurter Allgemeine Zeitung. from October 6, 2011.
7. ^ Medtronic pacemaker turns 50. In: RP Online. from October 7, 2011.
8. ↑ Plutonium pacemaker with illustrations.
9. ↑ Plutonium pacemaker, atomic battery in the chest. Spiegel Online, November 22, 2009, accessed June 11, 2014 . 
10. ↑ Pacemaker with radioactive isotope batteries. (No longer available online.) Federal Office for Radiation Protection, August 19, 2016, archived from the original on July 11, 2016 ; accessed on June 10, 2017 . 
11. ↑ BfS - Further information - Pacemaker with radioactive isotope batteries. July 11, 2016, accessed August 10, 2020 . 
12. ↑ [1]
13. ↑ [2]
14. ↑ Only booking errors . In: Der Spiegel . No. 13 , 1977, pp. 109-110 ( online ).
15. ↑ On the trail of bats . In: Der Spiegel . No. 38 , 1979, pp. 104-109 ( online - Sept. 17, 1979 ).
16. ↑ Small special account . In: Der Spiegel . No. 30 , 1981, pp. 58-62 ( Online - July 20, 1981 ).
17. ↑ The pseudomoral one doesn't do that . In: Der Spiegel . No. 4 , 1983, p. 58-59 ( Online - Jan. 24, 1983 ).
18. ↑ Fröhlig, Carlsson, Jung a. a. (Ed.): Pacemaker and defibrillator therapy. Georg Thieme Verlag, 2006, ISBN 3-13-117181-2 , p. 414.
19. ^ C. Holmes: The Lithium / Iodine-Polyvinylpyridine Pacemaker Battery - 35 Years of Successful Clinical Use . In: ECS Transactions . tape 6 , no. 5 , 2007, p. 1–7 , doi : 10.1149 / 1.2790382 (free full text).
20. ↑ HG Borst, W. Klinner, H. Oelert: Heart surgery - The interventions on the heart and on the vessels near the heart . 2nd Edition. Springer Verlag, Berlin / Heidelberg 1991, p. 489-490 .
21. ↑ A. Bolz, W. Urbaszek: Technology in cardiology: An interdisciplinary presentation for engineers and medical professionals . Springer-Verlag, Berlin / Heidelberg 2002, p. 369-370 .
22. ↑ R. Kramme (Ed.): Medical technology - procedures - systems - information processing . 4th edition. Springer Science & Business Media, Berlin / Heidelberg 2011, ISBN 978-3-642-16186-5 , p. 631-633 .
23. ↑ Amitava Majumder, Anne Paschen: Medical working techniques. In: Jörg Braun, Roland Preuss (Ed.): Clinic Guide Intensive Care Medicine. 9th edition. Elsevier, Munich 2016, ISBN 978-3-437-23763-8 , pp. 29–93, here: pp. 70–73 ( Temporary pacemaker ), here: pp. 72 f.
24. ↑ Amitava Majumder, Anne Paschen: Medical working techniques. In: Jörg Braun, Roland Preuss (Ed.): Clinic Guide Intensive Care Medicine. 9th edition. Elsevier, Munich 2016, ISBN 978-3-437-23763-8 , pp. 29–93, here: pp. 70–73 ( temporary pacemaker ), here: p. 72 ( intracardiac stimulation ).
25. ^ Marianne Abele-Horn: Antimicrobial Therapy. Decision support for the treatment and prophylaxis of infectious diseases. With the collaboration of Werner Heinz, Hartwig Klinker, Johann Schurz and August Stich, 2nd, revised and expanded edition. Peter Wiehl, Marburg 2009, ISBN 978-3-927219-14-4 , p. 34 f. ( Infections from pacemakers ).
26. ↑ NBG Code = NASPE / BPEG Generic Pacemaker Code (NASPE: North American Society of Pacing and Electrophysiology; BPEG: British Pacing and Electrophysiology Group)
27. ↑ Reinhard Larsen: Anesthesia and intensive medicine in cardiac, thoracic and vascular surgery. (1st edition 1986) 5th edition. Springer, Berlin / Heidelberg / New York a. a. 1999, ISBN 3-540-65024-5 , pp. 456-458.
28. ↑ Berndt Lüderitz : Rhythm disorders of the heart. In: Rudolf Gross , Paul Schölmerich , Wolfgang Gerok : 1000 memoranda of internal medicine. Schattauer, Stuttgart / New York 1971; 4th, completely revised edition ibid 1989 (= UTB for Science / Uni-Taschenbücher. Volume 522), ISBN 3-7945-1282-0 , pp. 67–71, here: p. 70.
29. ↑ Amitava Majumder, Anne Paschen: Medical working techniques. In: Jörg Braun, Roland Preuss (Ed.): Clinic Guide Intensive Care Medicine. 9th edition. Elsevier, Munich 2016, ISBN 978-3-437-23763-8 , pp. 29–93, here: pp. 70–73 ( Temporary Pacemaker ).
30. ↑ Biotronik: Possible interference from the implant ( Memento from July 21, 2012 in the web archive archive.today ). Retrieved May 3, 2012.
31. ↑ Medtronic: MRI-compatible pacemaker Advisa MRI and Ensura MRI SureScan ( Memento from September 8, 2012 in the web archive archive.today ). May 2011, accessed May 3, 2012.
32. ↑ St. Jude Medical: Conditional MRI-safe pacemaker, profile . ( Memento of May 18, 2013 in the Internet Archive ; PDF) September 2011; Retrieved May 3, 2012.
33. ↑ How far away do I have to keep my cell phone from a pacemaker? Quarks & Co ( Memento from June 25, 2008 in the Internet Archive )
34. ↑ Heike E. Krüger-Brand: Hacker attacks on pacemakers. In: Dtsch Arztebl . Volume 105, No. 33, 2008, pp. A-1749 ( online ).
    Original articles: Daniel Halperin, Thomas S. Heydt-Benjamin, Benjamin Ransford, Shane S. Clark, Benessa Defend, Will Morgan, Kevin Fu, Tadayoshi Kohno, William H. Maisel: Pacemakers and Implantable Cardiac Defibrillators: Software Radio Attacks and Zero-Power Defenses . In: IEEE Symposium on Security and Privacy, 2008 . IEEE, 2008, ISBN 978-0-7695-3168-7 , doi : 10.1109 / SP.2008.31 ( secure-medicine.org [PDF]).
35. ↑ Michael S. Lampadius: cardiac pacemaker type index. FGS-Forschungsgesellschaft Elektrostimulation mbH, 2019, accessed on April 12, 2019 . 
36. ↑ Annual Report 2016, Part 1: Pacemaker (PDF) German Pacemaker and Defibrillator Register, p. 9.

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