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An artificial cardiac pacemaker (or artificial pacemaker, so as not to be confused with the natural
cardiac pacemaker 350px, Image showing the cardiac pacemaker or SA node, the primary pacemaker within the electrical_conduction_system_of_the_heart">SA_node,_the_primary_pacemaker_within_the_electrical_conduction_system_of_the_heart. The_muscle_contraction.htm ...
) or pacemaker is a
medical device A medical device is any device intended to be used for medical purposes. Significant potential for hazards are inherent when using a device for medical purposes and thus medical devices must be proved safe and effective with reasonable assura ...
that generates electrical impulses delivered by
electrode An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials ...
s to the chambers of the heart either the upper atria, or lower ventricles to cause the targeted chambers to
contract A contract is a legally enforceable agreement between two or more parties that creates, defines, and governs mutual rights and obligations between them. A contract typically involves the transfer of goods, services, money, or a promise to tr ...
and pump blood. By doing so, the pacemaker regulates the function of the
electrical conduction system of the heart The cardiac conduction system (CCS) (also called the electrical conduction system of the heart) transmits the signals generated by the sinoatrial node – the heart's pacemaker, to cause the heart muscle to contract, and pump blood through ...
. The primary purpose of a pacemaker is to maintain an adequate
heart rate Heart rate (or pulse rate) is the frequency of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excr ...
, either because the heart's natural pacemaker is not fast enough, or because there is a block in the heart's electrical conduction system. Modern pacemakers are externally programmable and allow a cardiologist, particularly a cardiac electrophysiologist, to select the optimal pacing modes for individual patients. Most pacemakers are on demand, in which the stimulation of the heart is based on the dynamic demand of the
circulatory system The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, tha ...
. Others send out a fixed rate of impulses. A specific type of pacemaker called an implantable cardioverter-defibrillator combines pacemaker and
defibrillator Defibrillation is a treatment for life-threatening cardiac arrhythmias, specifically ventricular fibrillation (V-Fib) and non-perfusing ventricular tachycardia (V-Tach). A defibrillator delivers a dose of electric current (often called a ''coun ...
functions in a single implantable device. Others, called biventricular pacemakers, have multiple electrodes stimulating different positions within the ventricles (the lower heart chambers) to improve their synchronization.


Methods of pacing


Percussive pacing

Percussive pacing, also known as transthoracic mechanical pacing, is the use of the closed fist, usually on the left lower edge of the sternum over the
right ventricle A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the uppe ...
in the ''vena cava'', striking from a distance of 20 – 30 cm to induce a ventricular beat (the ''British Journal of Anaesthesia'' suggests this must be done to raise the ventricular pressure to 10–15 mmHg to induce electrical activity). This is an old procedure used only as a life-saving means until an electrical pacemaker is brought to the patient.


Transcutaneous pacing

Transcutaneous pacing (TCP), also called external pacing, is recommended for the initial stabilization of hemodynamically significant
bradycardia Bradycardia (also sinus bradycardia) is a slow resting heart rate, commonly under 60 beats per minute (BPM) as determined by an electrocardiogram. It is considered to be a normal heart rate during sleep, in young and healthy or elderly adults, ...
s of all types. The procedure is performed by placing two pacing pads on the patient's chest, either in the anterior/lateral position or the anterior/posterior position. The rescuer selects the pacing rate, and gradually increases the pacing current (measured in mA) until electrical capture (characterized by a wide
QRS complex The QRS complex is the combination of three of the graphical deflections seen on a typical electrocardiogram (ECG or EKG). It is usually the central and most visually obvious part of the tracing. It corresponds to the depolarization of the ri ...
with a tall, broad
T wave In electrocardiography, the T wave represents the repolarization of the ventricles. The interval from the beginning of the QRS complex to the apex of the T wave is referred to as the ''absolute refractory period''. The last half of the T wave ...
on the ECG) is achieved, with a corresponding pulse. Pacing artifact on the ECG and severe muscle twitching may make this determination difficult. External pacing should not be relied upon for an extended period of time. It is an emergency procedure that acts as a bridge until transvenous pacing or other therapies can be applied.


Epicardial pacing (temporary)

Temporary epicardial pacing is used during open heart surgery should the surgical procedure create atrio-ventricular block. The electrodes are placed in contact with the outer wall of the ventricle (epicardium) to maintain satisfactory cardiac output until a temporary transvenous electrode has been inserted.


Transvenous pacing (temporary)

Transvenous pacing, when used for temporary pacing, is an alternative to transcutaneous pacing. A pacemaker wire is placed into a vein, under sterile conditions, and then passed into either the right atrium or right ventricle. The pacing wire is then connected to an external pacemaker outside the body. Transvenous pacing is often used as a bridge to permanent pacemaker placement. It can be kept in place until a permanent pacemaker is implanted or until there is no longer a need for a pacemaker and then it is removed.


Permanent transvenous pacing

Permanent pacing with an implantable pacemaker involves transvenous placement of one or more pacing electrodes within a chamber, or chambers, of the heart, while the pacemaker is implanted inside the skin under the clavicle. The procedure is performed by incision of a suitable vein into which the electrode
lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, ...
is inserted and passed along the vein, through the valve of the heart, until positioned in the chamber. The procedure is facilitated by
fluoroscopy Fluoroscopy () is an imaging technique that uses X-rays to obtain real-time moving images of the interior of an object. In its primary application of medical imaging, a fluoroscope () allows a physician to see the internal structure and function ...
which enables the physician to view the passage of the electrode lead. After satisfactory lodgement of the electrode is confirmed, the opposite end of the electrode lead is connected to the pacemaker generator. There are three basic types of permanent pacemakers, classified according to the number of chambers involved and their basic operating mechanism: * ''Single-chamber pacemaker''. In this type, only one pacing lead is placed into a chamber of the heart, either the atrium or the ventricle. * ''Dual-chamber pacemaker''. Here, wires are placed in two chambers of the heart. One lead paces the atrium and one paces the ventricle. This type more closely resembles the natural pacing of the heart by assisting the heart in coordinating the function between the atria and ventricles. *''Biventricular pacemaker''. This pacemaker has three wires placed in three chambers of the heart. One in the atrium and two in either ventricle. It is more complicated to implant. * ''Rate-responsive pacemaker''. This pacemaker has sensors that detect changes in the patient's physical activity and automatically adjust the pacing rate to fulfill the body's metabolic needs. The pacemaker generator is a
hermetically sealed A hermetic seal is any type of sealing that makes a given object airtight (preventing the passage of air, oxygen, or other gases). The term originally applied to airtight glass containers, but as technology advanced it applied to a larger categor ...
device containing a power source, usually a
lithium battery Lithium battery may refer to: * Lithium metal battery, a non-rechargeable battery with lithium as an anode ** Rechargeable lithium metal battery, a rechargeable counterpart to the lithium metal battery * Lithium-ion battery, a rechargeable batte ...
, a sensing amplifier which processes the electrical manifestation of naturally occurring heart beats as sensed by the heart electrodes, the
computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations ( computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These prog ...
logic for the pacemaker and the output circuitry which delivers the pacing impulse to the electrodes. Most commonly, the generator is placed below the subcutaneous fat of the chest wall, above the muscles and bones of the chest. However, the placement may vary on a case-by-case basis. The outer casing of pacemakers is so designed that it will rarely be rejected by the body's
immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...
. It is usually made of
titanium Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion i ...
, which is inert in the body.


Leadless pacing

Leadless pacemakers are devices that are small enough to allow the generator to be placed within the heart, therefore avoiding the need for pacing leads. As pacemaker leads can fail over time, a pacing system that avoids these components offers theoretical advantages. Leadless pacemakers can be implanted into the heart using a steerable catheter fed into the
femoral vein In the human body, the femoral vein is a blood vessel that accompanies the femoral artery in the femoral sheath. It begins at the adductor hiatus (an opening in the adductor magnus muscle) as the continuation of the popliteal vein. It ends a ...
via an incision in the groin.


Basic function

Modern pacemakers usually have multiple functions. The most basic form monitors the heart's native electrical rhythm. When the pacemaker wire or "lead" does not detect heart electrical activity in the chamber – atrium or ventricle – within a normal beat-to-beat time period – most commonly one second – it will stimulate either the atrium or the ventricle with a short low voltage pulse. If it does sense electrical activity, it will hold off stimulating. This sensing and stimulating activity continues on a beat by beat basis and is called "demand pacing". In the case of a dual-chamber device, when the upper chambers have a spontaneous or stimulated activation, the device starts a countdown to ensure that in an acceptable – and programmable – interval, there is an activation of the ventricle, otherwise again an impulse will be delivered. The more complex forms include the ability to sense and/or stimulate both the atrial and ventricular chambers. From this the basic ventricular "on demand" pacing mode is VVI or with automatic rate adjustment for exercise VVIR – this mode is suitable when no synchronization with the atrial beat is required, as in atrial fibrillation. The equivalent atrial pacing mode is AAI or AAIR which is the mode of choice when atrioventricular conduction is intact but the natural pacemaker the sinoatrial node is unreliable – sinus node disease (SND) or
sick sinus syndrome Sinus node dysfunction (SND), also known as sick sinus syndrome (SSS), is a group of abnormal heart rhythms (arrhythmias) usually caused by a malfunction of the sinus node, the heart's primary pacemaker. Tachycardia-bradycardia syndrome is a varian ...
. Where the problem is atrioventricular block (AVB) the pacemaker is required to detect (sense) the atrial beat and after a normal delay (0.1–0.2 seconds) trigger a ventricular beat, unless it has already happened – this is VDD mode and can be achieved with a single pacing lead with electrodes in the right atrium (to sense) and ventricle (to sense and pace). These modes AAIR and VDD are unusual in the US but widely used in Latin America and Europe. The DDDR mode is most commonly used as it covers all the options though the pacemakers require separate atrial and ventricular leads and are more complex, requiring careful programming of their functions for optimal results. Automatic pacemakers are designed to be over-ridden by the heart's natural rate at any moment that it gets back to a non-pathologic
normal sinus rhythm A sinus rhythm is any cardiac rhythm in which depolarisation of the cardiac muscle begins at the sinus node. It is characterised by the presence of correctly oriented P waves on the electrocardiogram (ECG). Sinus rhythm is necessary, but not s ...
and can reinitiate influencing the electric activity in the heart when the pathologic event happens again. A " ventricular-demand pacemaker" produces a narrow vertical spike on the ECG, just before a wide QRS. The spike of an " atrial-demand pacemaker" appears just before the P wave. Comparably, a Triggered Pacemaker is activated immediately after an electrical activity is commenced in the heart tissue by itself. A "ventricular triggered pacemaker" produces the impulse just after a pulse is created in the ventricular tissue and it appears as a simultaneous spike with QRS. An "atrial triggered pacemaker" is the mode in which an impulse is produced immediately after an electrical event in the atrium. It appears as a
discharge Discharge may refer to Expel or let go * Discharge, the act of firing a gun * Discharge, or termination of employment, the end of an employee's duration with an employer * Military discharge, the release of a member of the armed forces from ser ...
following the p wave but prior to the QRS which is commonly widened.


Biventricular pacing

Cardiac resynchronization therapy (CRT) is used for people with
heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...
in whom the left and right ventricles do not contract simultaneously ( ventricular dyssynchrony), which occurs in approximately 25–50% of heart failure patients. To achieve CRT, a biventricular pacemaker (BVP) is used, which can pace both the septal and lateral walls of the
left ventricle A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the uppe ...
. By pacing both sides of the left ventricle, the pacemaker can resynchronize the ventricular contractions. CRT devices have at least two leads, one passing through the ''vena cava'' and the right atrium into the
right ventricle A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the uppe ...
to stimulate the
septum In biology, a septum (Latin for ''something that encloses''; plural septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interat ...
, and another passing through the ''vena cava'' and the right atrium and inserted through the
coronary sinus In anatomy, the coronary sinus () is a collection of veins joined together to form a large vessel that collects blood from the heart muscle (myocardium). It delivers deoxygenated blood to the right atrium, as do the superior and inferior vena ...
to pace the epicardial wall of the left ventricle. Often, for patients in normal sinus rhythm, there is also a lead in the right atrium to facilitate synchrony with the atrial contraction. Thus, the timing between the atrial and ventricular contractions, as well as between the septal and lateral walls of the left ventricle can be adjusted to achieve optimal cardiac function. CRT devices have been shown to reduce mortality and improve quality of life in patients with heart failure symptoms; a LV ejection fraction less than or equal to 35% and QRS duration on EKG of 120 ms or greater. Biventricular pacing alone is referred to as CRT-P (for pacing). For selected patients at risk of arrhythmias, CRT can be combined with an implantable cardioverter-defibrillator (ICD): such devices, known as CRT-D (for defibrillation), also provide effective protection against life-threatening arrhythmias.


Bundle pacing

Conventional placement of ventricular leads in or around the tip or ''apex'' of the right ventricle, or RV apical pacing, can have negative effects on heart function. It has been associated with increased risk of atrial fibrillation,
heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...
, weakening of the heart muscle and potentially shorter life expectancy. His bundle pacing (HBP) leads to a more natural or perfectly natural ventricular activation and has generated strong research and clinical interest. By stimulating the His–Purkinje fiber network directly with a special lead and placement technique, HBP causes a synchronized and therefore more effective ventricular activation and avoids long-term heart muscle disease. HBP in some cases can also correct
bundle branch block A bundle branch block is a defect in one the bundle branches in the electrical conduction system of the heart. Anatomy and physiology The heart's electrical activity begins in the sinoatrial node (the heart's natural pacemaker), which is situat ...
patterns.


Advancements in function

A major step forward in pacemaker function has been to attempt to mimic nature by utilizing various inputs to produce a rate-responsive pacemaker using parameters such as the
QT interval The QT interval is a measurement made on an electrocardiogram used to assess some of the electrical properties of the heart. It is calculated as the time from the start of the Q wave to the end of the T wave, and approximates to the time taken ...
, pO2 – pCO2 (dissolved
oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements ...
or
carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is t ...
levels) in the arterial-venous system, physical activity as determined by an
accelerometer An accelerometer is a tool that measures proper acceleration. Proper acceleration is the acceleration (the rate of change of velocity) of a body in its own instantaneous rest frame; this is different from coordinate acceleration, which is acce ...
,
body temperature Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperatur ...
, ATP levels,
adrenaline Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands an ...
, etc. Instead of producing a static, predetermined heart rate, or intermittent control, such a pacemaker, a 'Dynamic Pacemaker', could compensate for both actual respiratory loading and potentially anticipated respiratory loading. The first dynamic pacemaker was invented by Anthony Rickards of the
National Heart Hospital University College Hospital at Westmoreland Street, named The Heart Hospital until refurbished and renamed in 2015, was a specialist cardiac hospital located in London, United Kingdom until 2015. It is part of the University College London Hosp ...
, London, UK, in 1982. Dynamic pacemaking technology could also be applied to future
artificial heart An artificial heart is a device that replaces the heart. Artificial hearts are typically used to bridge the time to heart transplantation, or to permanently replace the heart in the case that a heart transplant (from a deceased human or, exper ...
s. Advances in transitional tissue welding would support this and other artificial organ/joint/tissue replacement efforts. Stem cells may be of interest in transitional tissue welding. Many advancements have been made to improve the control of the pacemaker once implanted. Many of these have been made possible by the transition to
microprocessor A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circ ...
controlled pacemakers. Pacemakers that control not only the ventricles but the atria as well have become common. Pacemakers that control both the atria and ventricles are called dual-chamber pacemakers. Although these dual-chamber models are usually more expensive, timing the contractions of the atria to precede that of the ventricles improves the pumping efficiency of the heart and can be useful in congestive heart failure. Rate responsive pacing allows the device to sense the physical activity of the patient and respond appropriately by increasing or decreasing the base pacing rate via rate response algorithms. The DAVID trials have shown that unnecessary pacing of the right ventricle can exacerbate
heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...
and increases the incidence of atrial fibrillation. The newer dual-chamber devices can keep the amount of right ventricle pacing to a minimum and thus prevent worsening of the heart disease.


Considerations


Insertion

A pacemaker may be implanted whilst a person is awake using
local anesthetic A local anesthetic (LA) is a medication that causes absence of pain sensation. In the context of surgery, a local anesthetic creates an absence of pain in a specific location of the body without a loss of consciousness, as opposed to a general a ...
to numb the skin with or without
sedation Sedation is the reduction of irritability or agitation by administration of sedative drugs, generally to facilitate a medical procedure or diagnostic procedure. Examples of drugs which can be used for sedation include isoflurane, diethyl ether, ...
, or asleep using a
general anesthetic General anaesthetics (or anesthetics, see spelling differences) are often defined as compounds that induce a loss of consciousness in humans or loss of righting reflex in animals. Clinical definitions are also extended to include an induced com ...
. An antibiotic is usually given to reduce the risk of infection. Pacemakers are generally implanted in the front of the chest in the region of the left or right shoulder. The skin is prepared by clipping or shaving any hair over the implant site before cleaning the skin with a disinfectant such as
chlorhexidine Chlorhexidine (CHX) (commonly known by the salt forms chlorhexidine gluconate and chlorhexidine digluconate (CHG) or chlorhexidine acetate) is a disinfectant and antiseptic that is used for skin disinfection before surgery and to sterilize surgi ...
. An incision is made below the collar bone and a space or pocket is created under the skin to house the pacemaker generator. This pocket is usually created just above the
pectoralis major The pectoralis major () is a thick, fan-shaped or triangular convergent muscle, situated at the chest of the human body. It makes up the bulk of the chest muscles and lies under the breast. Beneath the pectoralis major is the pectoralis minor, ...
muscle (prepectoral), but in some cases the device may be inserted beneath the muscle (submuscular). The lead or leads are fed into the heart through a large vein guided by X-ray imaging (
fluoroscopy Fluoroscopy () is an imaging technique that uses X-rays to obtain real-time moving images of the interior of an object. In its primary application of medical imaging, a fluoroscope () allows a physician to see the internal structure and function ...
). The tips of the leads may be positioned within the
right ventricle A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the uppe ...
, the right atrium, or the coronary sinus, depending on the type of pacemaker required. Surgery is typically completed within 30 to 90 minutes. Following implantation, the surgical wound should be kept clean and dry until it has healed. Care should be taken to avoid excessive movement of the shoulder within the first few weeks to reduce the risk of dislodging the pacemaker leads. The batteries within a pacemaker generator typically last 5 to 10 years. When the batteries are nearing the end of life, the generator is replaced in a procedure that is usually simpler than a new implant. Replacement involves making an incision to remove the existing device, disconnecting the leads from the old device and reconnecting them to a new generator, reinserting the new device and closing the skin.


Periodic pacemaker checkups

Once the pacemaker is implanted, it is periodically checked to ensure the device is operational and performing appropriately. Depending on the frequency set by the following physician, the device can be checked as often as is necessary. Routine pacemaker checks are typically done in-office every six months, though will vary depending upon patient/device status and remote monitoring availability. Newer pacemaker models can also be interrogated remotely, with the patient transmitting their pacemaker data using an at-home transmitter connected to their geographical cellular network. This data can then be accessed by the technician through the device manufacturer's web portal. At the time of in-office follow-up, the device will be interrogated to perform diagnostic testing. These tests include: * Sensing: the ability of the device to "see" intrinsic cardiac activity (Atrial and ventricular depolarization). * Impedance: A test to measure lead integrity. Large and/or sudden increases in impedance can be indicative of a lead fracture while large and/or sudden decreases in impedance can signify a breach in lead insulation. * Threshold amplitude: The minimum amount of energy (generally in hundredths of volts) required in order to pace the atrium or ventricle connected to the lead. * Threshold duration: The amount of time that the device requires at the preset amplitude to reliably pace the atrium or ventricle connected to the lead. * Percentage of pacing: Defines how dependent the patient is on the device, the percentage of time that the pacemaker has been actively pacing since the previous device interrogation. * Estimated battery life at current rate: As modern pacemakers are "on-demand", meaning that they only pace when necessary, device longevity is affected by how much it is utilized. Other factors affecting device longevity include programmed output and algorithms (features) causing a higher level of current drain from the battery. * Any events that were stored since the last follow-up, in particular arrhythmias such as atrial fibrillation. These are typically stored based on specific criteria set by the physician and specific to the patient. Some devices have the availability to display intracardiac electrograms of the onset of the event as well as the event itself. This is especially helpful in diagnosing the cause or origin of the event and making any necessary programming changes.


Magnetic fields, MRIs, and other lifestyle issues

A patient's lifestyle is usually not modified to any great degree after the insertion of a pacemaker. There are a few activities that are unwise, such as full-contact sports and activities that involve intense magnetic fields. The pacemaker patient may find that some types of everyday actions need to be modified. For instance, the shoulder harness of a vehicle seatbelt may be uncomfortable if the harness should fall across the pacemaker insertion site. Women will not be able to wear bras for a while after the operation and later might have to wear bras with wide shoulder straps. If the patient does wish to practice any type of sport or physical activity, special pacemaker protection can be worn to prevent possible physical injuries or damage to the pacemaker leads. Any kind of an activity that involves intense electro-magnetic fields should be avoided. This includes activities such as arc welding possibly, with certain types of equipment, or maintaining heavy equipment that may generate intense magnetic fields (such as a
magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio wave ...
(MRI) machine). However, in February 2011 the FDA approved a new pacemaker device from
Medtronic Medtronic plc is an American medical device company. The company's operational and executive headquarters are in Minneapolis, Minnesota, and its legal headquarters are in Ireland due to its acquisition of Irish-based Covidien in 2015. While it ...
called the Revo MRI SureScan which was the first to be labeled as
conditional Conditional (if then) may refer to: *Causal conditional, if X then Y, where X is a cause of Y *Conditional probability, the probability of an event A given that another event B has occurred *Conditional proof, in logic: a proof that asserts a co ...
for MRI use. There are several limitations to its use including certain patients' qualifications and scan settings. An MRI conditional device has to be reprogrammed right before and right after MRI scanning. All the 5 most common cardiac pacing device manufacturers (covering more than 99% of the US market) now have FDA-approved MR-conditional pacemakers. A 2008 US study has found that the magnetic field created by some headphones included with portable music players or cell phones, when placed within inches of pacemakers, may cause interference. In addition, according to the
American Heart Association The American Heart Association (AHA) is a nonprofit organization in the United States that funds cardiovascular medical research, educates consumers on healthy living and fosters appropriate cardiac care in an effort to reduce disability and deat ...
, some home devices have a remote potential to cause interference by occasionally inhibiting a single beat. Cellphones available in the United States (less than 3 watts) do not seem to damage pulse generators or affect how the pacemaker works. Having a pacemaker does not imply that a patient requires the use of
antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...
s to be administered before procedures such as dental work. The patient should inform all medical personnel that he or she has a pacemaker. The use of MRI may be ruled out by the patient having a pacemaker manufactured before MRI conditional devices became common, or by the patient having old pacing wires abandoned inside the heart, no longer connected to their pacemaker.


End-of-life care and pacemaker deactivation

A panel of the Heart Rhythm Society, a specialist organization based in Washington, DC, found that it was legal and ethical to honor requests by patients, or by those with legal authority to make decisions for patients, to deactivate implanted cardiac devices. Lawyers say that the legal situation is similar to removing a feeding tube, though there is currently no legal precedent involving pacemakers in the United States. A patient in the US is thought to have a right to refuse or discontinue treatment, including a pacemaker that keeps him or her alive. Physicians have a right to refuse to turn it off, but are advised by the HRS panel that they should refer the patient to a physician who will. Some patients believe that hopeless, debilitating conditions, like those brought on by severe strokes or late-stage dementia, can cause so much suffering that they would prefer not to prolong their lives with supportive measures, such as cardiac devices.


Privacy and security

Security and privacy concerns have been raised with pacemakers that allow wireless communication. Unauthorized third parties may be able to read patient records contained in the pacemaker, or reprogram the devices, as has been demonstrated by a team of researchers. The demonstration worked at short range; they did not attempt to develop a long range antenna. The proof of concept exploit helps demonstrate the need for better security and patient alerting measures in remotely accessible medical implants. In response to this threat, Purdue University and Princeton University researchers have developed a prototype firewall device, called MedMon, which is designed to protect wireless medical devices such as pacemakers and insulin pumps from attackers.


Complications

Complications from having
surgery Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pa ...
to implant a
pacemaker An artificial cardiac pacemaker (or artificial pacemaker, so as not to be confused with the natural cardiac pacemaker) or pacemaker is a medical device that generates electrical impulses delivered by electrodes to the chambers of the heart ei ...
are uncommon (each 1-3% approximately), but could include: infection where the pacemaker is implanted or in the bloodstream;
allergic reaction Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derm ...
to the dye or
anesthesia Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), ...
used during the procedure; swelling, bruising or bleeding at the generator site, or around the heart, especially if the patient is taking
blood thinners Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where the ...
, elderly, of thin frame or otherwise on chronic
steroids A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and ...
use. A possible complication of dual-chamber artificial pacemakers is 'pacemaker-mediated tachycardia' (PMT), a form of reentrant tachycardia. In PMT, the artificial pacemaker forms the anterograde (atrium to ventricle) limb of the circuit and the atrioventricular (AV) node forms the retrograde limb (ventricle to atrium) of the circuit. Treatment of PMT typically involves reprogramming the pacemaker. Another possible complication is "pacemaker-tracked tachycardia," where a supraventricular tachycardia such as atrial fibrillation or
atrial flutter Atrial flutter (AFL) is a common abnormal heart rhythm that starts in the atrial chambers of the heart. When it first occurs, it is usually associated with a fast heart rate and is classified as a type of supraventricular tachycardia. Atrial f ...
is tracked by the pacemaker and produces beats from a ventricular lead. This is becoming exceedingly rare as newer devices are often programmed to recognize supraventricular tachycardias and switch to non-tracking modes. Sometimes the leads, which are small diameter wires, from the pacemaker to the implantation site in the heart muscle will need to be removed. The most common reason for lead removal is infection, however over time leads can degrade due to a number of reasons such as lead flexing.Transvenous Lead Extraction: Heart Rhythm Society Expert Consensus on Facilities, Training, Indications, and Patient Management
Author: Bruce L. Wilkoff. Coauthor(s): Charles J. Love, Charles L. Byrd, Maria Grazia Bongiorni, Roger G. Carrillo, George H. Crossley III, Laurence M. Epstein, Richard A. Friedman, Charles E. H. Kennergren, Przemyslaw Mitkowski, Raymond H. M. Schaerf, Oussama M. Wazni
Changes to the programming of the pacemaker may overcome lead degradation to some extent. However, a patient who has several pacemaker replacements over a decade or two in which the leads were reused may require a lead replacement surgery. Lead replacement may be done in one of two ways. Insert a new set of leads without removing the current leads (not recommended as it provides additional obstruction to blood flow and heart valve function) or remove the current leads and then insert replacements. The lead removal technique will vary depending on the surgeon's estimation of the probability that simple traction will suffice to more complex procedures. Leads can normally be disconnected from the pacemaker easily which is why device replacement usually entails simple surgery to access the device and replace it by simply unhooking the leads from the device to replace and hooking the leads to the new device. The possible complications, such as perforation of the heart wall, come from removing the lead from the patient's body. The other end of a pacemaker lead is actually implanted into the heart muscle with a miniature screw or anchored with small plastic hooks called tines. In addition, the longer the leads have been implanted starting from a year or two, the more likely that they will have attachments to the patient's body at various places in the pathway from device to heart muscle, since the human body tends to incorporate foreign devices into tissue. In some cases, for a lead that has been inserted for a short amount of time, removal may involve simple traction to pull the lead from the body. Removal in other cases is typically done with a laser or cutting device which threads like a cannula with a cutting edge over the lead and is moved down the lead to remove any organic attachments with tiny cutting lasers or similar device. Pacemaker lead malposition in various locations has been described in the literature. Treatment varies, depending on the location of the pacer lead and symptoms. Another possible complication called
twiddler's syndrome Twiddler's syndrome is a malfunction of a pacemaker due to manipulation of the device and the consequent dislodging of the leads from their intended location. As the leads move, they stop pacing the heart and can cause strange symptoms such as ph ...
occurs when a patient manipulates the pacemaker and causes the leads to be removed from their intended location and causes possible stimulation of other nerves. Overall life expectancy with pacemakers is excellent, and mostly depends upon underlying diseases, presence of atrial fibrillation, age and sex at the time of first implantation.


Other devices

Sometimes devices resembling pacemakers, called implantable cardioverter-defibrillators (ICDs) are implanted. These devices are often used in the treatment of patients at risk from sudden cardiac death. An ICD has the ability to treat many types of heart rhythm disturbances by means of pacing,
cardioversion Cardioversion is a medical procedure by which an abnormally fast heart rate ( tachycardia) or other cardiac arrhythmia is converted to a normal rhythm using electricity or drugs. Synchronized electrical cardioversion uses a therapeutic dose ...
, or
defibrillation Defibrillation is a treatment for life-threatening cardiac arrhythmias, specifically ventricular fibrillation (V-Fib) and non-perfusing ventricular tachycardia (V-Tach). A defibrillator delivers a dose of electric current (often called a ''coun ...
. Some ICD devices can distinguish between ventricular fibrillation and
ventricular tachycardia Ventricular tachycardia (V-tach or VT) is a fast heart rate arising from the lower chambers of the heart. Although a few seconds of VT may not result in permanent problems, longer periods are dangerous; and multiple episodes over a short period ...
(VT), and may try to pace the heart faster than its intrinsic rate in the case of VT, to try to break the tachycardia before it progresses to ventricular fibrillation. This is known as ''fast-pacing'', ''overdrive pacing'', or ''anti-tachycardia pacing'' (ATP). ATP is only effective if the underlying rhythm is ventricular tachycardia, and is never effective if the rhythm is ventricular fibrillation.


History


Origin

In 1889, John Alexander MacWilliam reported in the ''
British Medical Journal ''The BMJ'' is a weekly peer-reviewed medical trade journal, published by the trade union the British Medical Association (BMA). ''The BMJ'' has editorial freedom from the BMA. It is one of the world's oldest general medical journals. Origi ...
'' (BMJ) of his experiments in which application of an electrical impulse to the human heart in
asystole Asystole (New Latin, from Greek privative a "not, without" + ''systolē'' "contraction") is the absence of ventricular contractions in the context of a lethal heart arrhythmia (in contrast to an induced asystole on a cooled patient on a heart-lu ...
caused a ventricular contraction and that a heart rhythm of 60–70 beats per minute could be evoked by impulses applied at spacings equal to 60–70/minute. In 1926, Mark C Lidwill of the Royal Prince Alfred Hospital of Sydney, supported by physicist Edgar H. Booth of the
University of Sydney The University of Sydney (USYD), also known as Sydney University, or informally Sydney Uni, is a public research university located in Sydney, Australia. Founded in 1850, it is the oldest university in Australia and is one of the country's si ...
, devised a portable apparatus which "plugged into a lighting point" and in which "One pole was applied to a skin pad soaked in strong salt solution" while the other pole "consisted of a needle insulated except at its point, and was plunged into the appropriate cardiac chamber". "The pacemaker rate was variable from about 80 to 120 pulses per minute, and likewise the voltage variable from 1.5 to 120 volts". In 1928, the apparatus was used to revive a
stillborn Stillbirth is typically defined as fetal death at or after 20 or 28 weeks of pregnancy, depending on the source. It results in a baby born without signs of life. A stillbirth can result in the feeling of guilt or grief in the mother. The ter ...
infant at
Crown Street Women's Hospital Crown Street Women's Hospital (now-closed) was once the largest maternity hospital in Sydney, New South Wales, Australia. It was located at 351 Crown Street (corner of Crown and Albion Streets), Surry Hills. The hospital was one of several ...
in Sydney, whose heart continued "to beat on its own accord", "at the end of 10 minutes" of stimulation. In 1932, American physiologist
Albert Hyman Albert Salisbury Hyman (1893 - 1972), a Harvard-trained New York cardiologist, together with his brother Charles, constructed in 1930-1932 an electro-mechanical device which was one of the earliest artificial pacemakers. The device was, reportedly, ...
, with the help of his brother, described an electro-mechanical instrument of his own, powered by a spring-wound hand-cranked motor. Hyman himself referred to his invention as an "artificial pacemaker", the term continuing in use to this day. An apparent
hiatus Hiatus may refer to: * Hiatus (anatomy), a natural fissure in a structure * Hiatus (stratigraphy), a discontinuity in the age of strata in stratigraphy *''Hiatus'', a genus of picture-winged flies with sole member species '' Hiatus fulvipes'' * G ...
in the publication of research conducted between the early 1930s and
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...
may be attributed to the public perception of interfering with nature by "reviving the dead". For example, "Hyman did not publish data on the use of his pacemaker in humans because of adverse publicity, both among his fellow physicians, and due to newspaper reporting at the time. Lidwell may have been aware of this and did not proceed with his experiments in humans".


Transcutaneous

In 1950, Canadian electrical engineer John Hopps designed and built the first external pacemaker based upon observations by cardio-thoracic surgeons Wilfred Gordon Bigelow and John Callaghan at
Toronto General Hospital The Toronto General Hospital (TGH) is a major teaching hospital in Toronto, Ontario, Canada and the flagship campus of University Health Network (UHN). It is located in the Discovery District of Downtown Toronto along University Avenue's Hospi ...
, although the device was first tested on a dog at the
University of Toronto The University of Toronto (UToronto or U of T) is a public research university in Toronto, Ontario, Canada, located on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution ...
's Banting Institute. A substantial external device using
vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. The type known as ...
technology to provide transcutaneous pacing, it was somewhat crude and painful to the patient in use and, being powered from an AC wall socket, carried a potential hazard of
electrocution Electrocution is death or severe injury caused by electric shock from electric current passing through the body. The word is derived from "electro" and "execution", but it is also used for accidental death. The term "electrocution" was coin ...
of the patient and inducing
ventricular fibrillation Ventricular fibrillation (V-fib or VF) is an abnormal heart rhythm in which the ventricles of the heart quiver. It is due to disorganized electrical activity. Ventricular fibrillation results in cardiac arrest with loss of consciousness and n ...
. A number of innovators, including Paul Zoll, made smaller but still bulky transcutaneous pacing devices from 1952 using a large rechargeable battery as the power supply. In 1957, William L. Weirich published the results of research performed at the
University of Minnesota The University of Minnesota, formally the University of Minnesota, Twin Cities, (UMN Twin Cities, the U of M, or Minnesota) is a public land-grant research university in the Twin Cities of Minneapolis and Saint Paul, Minnesota, United States. ...
. These studies demonstrated the restoration of heart rate, cardiac output and mean aortic pressures in animal subjects with complete heart block through the use of a myocardial electrode. In 1958 Colombian doctor Alberto Vejarano Laverde and Colombian electrical engineer
Jorge Reynolds Pombo Jorge Reynolds Pombo is an electrical and bio- engineer born in Bogotá, Colombia on June 22, 1936. He is known for contributing to the invention of the pacemaker, being one of the first doctors in Latin America to make a significant contribution ...
constructed an external pacemaker, similar to those of Hopps and Zoll, weighing 45 kg and powered by a 12 volt car
lead–acid battery The lead–acid battery is a type of rechargeable battery first invented in 1859 by French physicist Gaston Planté. It is the first type of rechargeable battery ever created. Compared to modern rechargeable batteries, lead–acid batteries have ...
, but connected to electrodes attached to the heart. This apparatus was successfully used to sustain a 70-year-old priest, Gerardo Florez. The development of the
silicon Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic ...
transistor upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch ...
and its first commercial availability in 1956 was the pivotal event that led to the rapid development of practical cardiac pacemaking.


Wearable

In 1958, engineer
Earl Bakken Earl Elmer Bakken (January 10, 1924 – October 21, 2018) was an American engineer, businessman and philanthropist of Dutch and Norwegian American ancestry. He founded Medtronic, where he developed the first external, battery-operated, transi ...
of Minneapolis, Minnesota, produced the first wearable external pacemaker for a patient of
C. Walton Lillehei Clarence Walton Lillehei (October 23, 1918 – July 5, 1999), was an American surgeon who pioneered open-heart surgery, as well as numerous techniques, equipment and prostheses for cardiothoracic surgery. Background Clarence (often called " ...
. This transistorized pacemaker, housed in a small plastic box, had controls to permit adjustment of pacing heart rate and output voltage and was connected to electrode
leads Lead is a chemical element with symbol Pb and atomic number 82. Lead or The Lead may also refer to: Animal handling * Leash, or lead * Lead (leg), the leg that advances most in a quadruped's cantering or galloping stride * Lead (tack), a lin ...
which passed through the skin of the patient to terminate in electrodes attached to the surface of the
myocardium Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle tha ...
of the heart. In the UK in the 1960s, Lucas Engineering in
Birmingham Birmingham ( ) is a city and metropolitan borough in the metropolitan county of West Midlands in England. It is the second-largest city in the United Kingdom with a population of 1.145 million in the city proper, 2.92 million in the We ...
was asked by Mr Abrams of The Queen Elizabeth Hospital to produce a prototype for a transistorised replacement for the electro-mechanical product. The team was headed by Roger Nolan, an engineer with the Lucas Group Research Centre. Nolan designed and created the first blocking oscillator and transistor-powered pacemaker. This pacemaker was worn on a belt and powered by a rechargeable sealed battery, enabling users to live a more-normal life. One of the earliest patients to receive this Lucas pacemaker device was a woman in her early 30s. The operation was carried out in 1964 by South African cardiac surgeon (and later professor) Alf Gunning, a student of
Christiaan Barnard Christiaan Neethling Barnard (8 November 1922 – 2 September 2001) was a South African cardiac surgeon who performed the world's first human-to-human heart transplant operation. On 3 December 1967, Barnard transplanted the heart of accident-v ...
. This pioneering operation took place under the guidance of cardiac consultant Peter Sleight at the
Radcliffe Infirmary The Radcliffe Infirmary was a hospital in central north Oxford, England, located at the southern end of Woodstock Road on the western side, backing onto Walton Street. History The initial proposals to build a hospital in Oxford were put forw ...
in Oxford and his cardiac research team at St George's Hospital in London. Sleight later became a Professor of Cardiovascular Medicine at
Oxford University Oxford () is a city in England. It is the county town and only city of Oxfordshire. In 2020, its population was estimated at 151,584. It is north-west of London, south-east of Birmingham and north-east of Bristol. The city is home to the ...
.


Implantable

The first clinical implantation into a human of a fully implantable pacemaker was on October 8, 1958, at the
Karolinska Institute The Karolinska Institute (KI; sv, Karolinska Institutet; sometimes known as the (Royal) Caroline Institute in English) is a research-led medical university in Solna within the Stockholm urban area of Sweden. The Karolinska Institute is consist ...
in Solna,
Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic countries, Nordic c ...
, using a pacemaker designed by inventor
Rune Elmqvist Rune Elmqvist (1906–1996) developed the first implantable pacemaker in 1958, working under the direction of Åke Senning, senior physician and cardiac surgeon at the Karolinska University Hospital in Solna, Sweden. Elmqvist initially worked as ...
and surgeon
Åke Senning Åke Senning (* 14 December 1915 in Rättvik, Sweden; † 21 July 2000 in Zurich, Switzerland) was a Swedish cardiac surgeon who worked at Zurich University Hospital from 1961 until his retirement in 1985. Biography Åke Senning was born ...
(in collaboration with Elema-Schönander AB, later Siemens-Elema AB), connected to electrodes attached to the
myocardium Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle tha ...
of the heart by thoracotomy. The device failed after three hours. A second device was then implanted which lasted for two days. The world's first implantable pacemaker patient, Arne Larsson, went on to receive 26 different pacemakers during his lifetime. He died in 2001, at the age of 86, outliving the inventor as well as the surgeon. In 1959, temporary
transvenous pacing Transvenous cardiac pacing (TVP), also called endocardial pacing, is a potentially life-saving intervention used primarily to correct profound bradycardia. It can be used to treat symptomatic bradycardias that do not respond to transcutaneous pacin ...
was first demonstrated by Seymour Furman and John Schwedel, whereby the
catheter In medicine, a catheter (/ˈkæθətər/) is a thin tubing (material), tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgi ...
electrode was inserted via the patient's
basilic vein The basilic vein is a large superficial vein of the upper limb that helps drain parts of the hand and forearm. It originates on the medial ( ulnar) side of the dorsal venous network of the hand and travels up the base of the forearm, where its ...
. In February 1960, an improved version of the Swedish Elmqvist design was implanted in
Montevideo Montevideo () is the capital and largest city of Uruguay. According to the 2011 census, the city proper has a population of 1,319,108 (about one-third of the country's total population) in an area of . Montevideo is situated on the southern co ...
,
Uruguay Uruguay (; ), officially the Oriental Republic of Uruguay ( es, República Oriental del Uruguay), is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast; while bordering ...
in the Casmu 1 Hospital by Doctors Orestes Fiandra and Roberto Rubio. That device lasted until the patient died of other ailments, nine months later. The early Swedish-designed devices used rechargeable batteries, which were charged by an induction coil from the outside. It was the first pacemaker implanted in America. Implantable pacemakers constructed by engineer Wilson Greatbatch entered use in humans from April 1960 following extensive
animal testing Animal testing, also known as animal experimentation, animal research, and ''in vivo'' testing, is the use of non-human animals in experiments that seek to control the variables that affect the behavior or biological system under study. This ...
. The Greatbatch innovation varied from the earlier Swedish devices in using primary cells (
mercury battery A mercury battery (also called mercuric oxide battery, mercury cell, button cell, or Ruben-Mallory) is a non-rechargeable electrochemical battery, a primary cell. Mercury batteries use a reaction between mercuric oxide and zinc electrodes in an ...
) as the energy source. The first patient lived for a further 18 months. The first use of
transvenous pacing Transvenous cardiac pacing (TVP), also called endocardial pacing, is a potentially life-saving intervention used primarily to correct profound bradycardia. It can be used to treat symptomatic bradycardias that do not respond to transcutaneous pacin ...
in conjunction with an implanted pacemaker was by Parsonnet in the United States, Lagergren in Sweden and Jean-Jacques Welti in France in 1962–63. The transvenous, or pervenous, procedure involved incision of a vein into which was inserted the
catheter In medicine, a catheter (/ˈkæθətər/) is a thin tubing (material), tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgi ...
electrode lead under fluoroscopic guidance, until it was lodged within the trabeculae of the right ventricle. This method was to become the method of choice by the mid-1960s. Cardiothoracic surgeon
Leon Abrams Leon David Abrams FRCS (1923–2012) was a British cardiothoracic surgeon who developed and implanted the first variable rate heart pacemaker, together with Ray Lightwood, at the University of Birmingham. Leon Abrams was born in Leeds. He ...
and medical engineer
Ray Lightwood Raymond Lightwood (1922–2001) was a British medical engineer who developed the first variable rate heart pacemaker, together with Leon Abrams at the University of Birmingham. Ray Lightwood was born in Coventry. He was educated at Birchfield ...
developed and implanted the first patient-controlled variable-rate heart pacemaker in 1960 at
Birmingham University , mottoeng = Through efforts to heights , established = 1825 – Birmingham School of Medicine and Surgery1836 – Birmingham Royal School of Medicine and Surgery1843 – Queen's College1875 – Mason Science College1898 – Mason Univers ...
. The first implant took place in March 1960, with two further implants the following month. These three patients made good recoveries and returned to a high quality of life. By 1966, 56 patients had undergone implantation with one surviving for over years.


Lithium battery

The preceding implantable devices all suffered from the unreliability and short lifetime of the available primary cell technology which was mainly that of the
mercury battery A mercury battery (also called mercuric oxide battery, mercury cell, button cell, or Ruben-Mallory) is a non-rechargeable electrochemical battery, a primary cell. Mercury batteries use a reaction between mercuric oxide and zinc electrodes in an ...
. In the late 1960s, several companies, including
ARCO ARCO ( ) is a brand of gasoline stations currently owned by Marathon Petroleum after BP sold its rights. BP commercializes the brand in Northern California, Oregon and Washington, while Marathon has rights for the rest of the United States an ...
in the US, developed isotope-powered pacemakers, but this development was overtaken by the development in 1971 of the lithium iodide cell battery by Wilson Greatbatch. Lithium-iodide or lithium anode cells became the standard for future pacemaker designs. A further impediment to the reliability of the early devices was the diffusion of water vapor from the body fluids through the
epoxy Epoxy is the family of basic components or cured end products of epoxy resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide functional group is also co ...
resin encapsulation affecting the electronic circuitry. This phenomenon was overcome by encasing the pacemaker generator in a hermetically sealed metal case, initially by
Telectronics Telectronics Pty Ltd was an Australian company best known for its role in developing the pacemaker. It was located in Lane Cove, Sydney. In 1988 the business was acquired by Pacific Dunlop. and also However, legal claims resulting from the sale ...
of Australia in 1969 followed by
Cardiac Pacemakers, Inc. Cardiac Pacemakers, Inc.(CPI), Trade name, doing business as Guidant Cardiac Rhythm Management, manufactured implantable cardiac rhythm management devices, such as pacemakers and defibrillators. It sold microprocessor-controlled insulin pumps and ...
of
St. Paul, Minnesota Saint Paul (abbreviated St. Paul) is the capital of the U.S. state of Minnesota and the county seat of Ramsey County. Situated on high bluffs overlooking a bend in the Mississippi River, Saint Paul is a regional business hub and the center o ...
in 1972. This technology, using
titanium Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion i ...
as the encasing metal, became the standard by the mid-1970s. On July 9, 1974, the founders of
Cardiac Pacemakers, Inc. Cardiac Pacemakers, Inc.(CPI), Trade name, doing business as Guidant Cardiac Rhythm Management, manufactured implantable cardiac rhythm management devices, such as pacemakers and defibrillators. It sold microprocessor-controlled insulin pumps and ...
. ( Guidant), Manuel A. Villafaña and Anthony Adducci, manufactured the world's first pacemaker with a lithium anode and a lithium-iodide electrolyte solid-state battery. Lithium-iodide or lithium anode cells increased the life of pacemakers from 1 year up to 11 years and has become the standard for future pacemaker designs. They began designing and testing their implantable cardiac pacemaker powered with a new longer-life lithium battery in 1971. The first patient to receive a CPI pacemaker emerged from surgery in June 1973.


Intra-cardial

In 2013, multiple firms announced devices that could be inserted via a leg catheter rather than invasive surgery. The devices are roughly the size and shape of a pill, much smaller than the size of a traditional pacemaker. Once implanted, the device's prongs contact the muscle and stabilize heartbeats. Engineers and scientists are currently working on this type of device. In November 2014 a patient, Bill Pike of
Fairbanks, Alaska Fairbanks is a home rule city and the borough seat of the Fairbanks North Star Borough in the U.S. state of Alaska. Fairbanks is the largest city in the Interior region of Alaska and the second largest in the state. The 2020 Census put the p ...
, received a
Medtronic Medtronic plc is an American medical device company. The company's operational and executive headquarters are in Minneapolis, Minnesota, and its legal headquarters are in Ireland due to its acquisition of Irish-based Covidien in 2015. While it ...
Micra pacemaker in Providence St Vincent Hospital in
Portland Oregon Portland (, ) is a port city in the Pacific Northwest and the largest city in the U.S. state of Oregon. Situated at the confluence of the Willamette and Columbia rivers, Portland is the county seat of Multnomah County, the most populous co ...
. D. Randolph Jones was the EP doctor. Also in 2014, St. Jude Medical Inc. announced the first enrollments in the company's leadless Pacemaker Observational Study evaluating the Nanostim leadless pacing technology. The Nanostim pacemaker received CE marking in 2013. The post-approval implants have occurred in Europe. The European study was recently stopped, after there were reports of six perforations that led to two patient deaths. After investigations, St Jude Medical restarted the study. In the United States, however, this therapy is still not approved by the FDA. While the St Jude Nanostim and the Medtronic Micra are single-chamber pacemakers, it is anticipated that leadless dual-chamber pacing for patients with atrioventricular block will become possible with further development.


Reusable pacemakers

Thousands of pacemakers are removed by funeral home personnel each year all over the world. They must be removed postmortem from bodies that are going to be cremated to avoid explosions. It is a fairly simple procedure that can be carried out by a mortician. Pacemakers with significant battery life are potentially life-saving devices for people in low- and middle-income countries (LMICs). The
Institute of Medicine The National Academy of Medicine (NAM), formerly called the Institute of Medicine (IoM) until 2015, is an American nonprofit, non-governmental organization. The National Academy of Medicine is a part of the National Academies of Sciences, Eng ...
, a
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...
non-governmental organization A non-governmental organization (NGO) or non-governmental organisation (see spelling differences) is an organization that generally is formed independent from government. They are typically nonprofit entities, and many of them are active in ...
, has reported that inadequate access to advanced cardiovascular technologies is a major contributor to cardiovascular disease morbidity and mortality in LMICs. Ever since the 1970s, multiple studies worldwide have reported on the safety and efficacy of pacemaker reuse. , widely acceptable standards for safe pacemaker and ICD reuse have not been developed, and there continue to be legal and regulatory barriers to widespread adoption of medical device reuse.


Manufacturers

Current and prior manufacturers of implantable pacemakers *
Biotronik Biotronik (BIOTRONIK SE & Co. KG; Biotronik Worldwide) is a limited partnership multi-national cardiovascular biomedical research and technology company, headquartered in Berlin, Germany. The company offers equipment for diagnosis, treatment, ...
(Germany) * Boston Scientific (USA) * Cardiac Pacemaker Inc. ; Guidant (USA) (now owned by Boston Scientific) * Intermedics (USA) * Lepu Medical (China) * Medico (Italy) *
Medtronic Medtronic plc is an American medical device company. The company's operational and executive headquarters are in Minneapolis, Minnesota, and its legal headquarters are in Ireland due to its acquisition of Irish-based Covidien in 2015. While it ...
(USA) *
Sorin Group The Sorin Group was a medical products group based in Italy, with significant operations in France, the United States, and Japan, specializing in cardiac devices. Its product lines include replacement heart valves, oxygenators, perfusion tubing ...
(Italy) (merged with Cyberonics to form
LivaNova LivaNova, PLC is an American medical device manufacturer domiciled in the UK. The company develops devices used for cardiac surgery and neuromodulation. The company was formed in 2015 by a $2.7B merger between Houston, Texas-based Cyberonics, I ...
; in 2018, LivaNova sold its cardiac rhythm management business unit to MicroPort for $190M ) *
St. Jude Medical St. Jude Medical, Inc. was an American global medical device company headquartered in Little Canada, Minnesota, U.S., a suburb of Saint Paul. The company had more than 20 principal operations and manufacturing facilities worldwide with products s ...
(USA) (now owned by
Abbott Laboratories Abbott Laboratories is an American multinational medical devices and health care company with headquarters in Abbott Park, Illinois, United States. The company was founded by Chicago physician Wallace Calvin Abbott in 1888 to formulate known dr ...
)


See also

*
Biological pacemaker A biological pacemaker is one or more types of cellular components that, when "implanted or injected into certain regions of the heart," produce specific electrical stimuli that mimic that of the body's natural pacemaker cells. Biological pacemake ...
*
Button cell A button cell, watch battery, or coin battery is a small single-cell battery shaped as a squat cylinder typically in diameter and high — resembling a button. Stainless steel usually forms the bottom body and positive terminal of the cell; in ...
*
Electrical conduction system of the heart The cardiac conduction system (CCS) (also called the electrical conduction system of the heart) transmits the signals generated by the sinoatrial node – the heart's pacemaker, to cause the heart muscle to contract, and pump blood through ...
* Implantable cardioverter-defibrillator *
Infective endocarditis Infective endocarditis is an infection of the inner surface of the heart, usually the valves. Signs and symptoms may include fever, small areas of bleeding into the skin, heart murmur, feeling tired, and low red blood cell count. Complicatio ...
* Pacemaker syndrome


References


External links


Detecting and Distinguishing Cardiac Pacing Artifacts


* [https://web.archive.org/web/20100925001511/http://escardio.org/communities/EHRA/education/webinars/Pages/welcome.aspx Current indications for CRT-P and CRT-D: Webinar from the European Heart Rhythm Association (EHRA)] {{DEFAULTSORT:Pacemaker (artificial) 1959 introductions Cardiac electrophysiology Embedded systems Implants (medicine) Neuroprosthetics Prosthetics Cybernetics Biomedical engineering Medical devices Australian inventions Colombian inventions