pacemaker (or artificial pacemaker , so as not to confuse with natural pacemakers) is a medical device that generates electrical impulses sent by electrodes to contract the heart muscle and regulate electrical conduction system of the heart.
The main goal of a pacemaker is to maintain a sufficient heart rate, either because the heart pacemaker is not fast enough, or because there are blocks in the electrical conductive system of the heart. Modern pacemakers are programmed externally and allow cardiologists to choose the optimal mode of movement for each patient. Some combine pacemakers and defibrillators in a single implant device. Others have several electrodes that stimulate different positions inside the heart to improve synchronization of the lower chamber, or ventricle, of the heart.
Video Artificial cardiac pacemaker
Methods paced
Multiply percussion
The pacing percussion, also known as the transthoracic mechanical pacing, is the use of closed boxing, usually on the lower left edge of the sternum over the right ventricle in the cava vein, striking from a distance of 20-30 cm to induce a ventricular rhythm (The British Journal of Anesthesia) suggested this should be done to increase ventricular pressure up to 10-15 mmHg to induce electrical activity). This is an old procedure that is only used as a means of saving lives until a pacemaker is brought to the patient.
Transcutaneous pacemaker
Transcutaneous pacing (TCP), also called external pacing, is recommended for early stabilization of significant hemodynamic bradycardia of all types. This procedure is performed by placing two pacing pads on the patient's chest, either in the anterior/lateral position or the anterior/posterior position. Rescuers choose pacing speed, and gradually increase pacing current (measured in mA) to electric capture (marked by a wide QRS complex with a height, wide T wave at ECG) achieved, with appropriate pulses. Pacing artifacts on ECG and severe muscle twitching can make this determination difficult. External retreats are unreliable for long periods of time. This is an emergency procedure that serves as a bridge until a transvenus or other therapy can be applied.
Epicardial runway (temporary)
Periodic epicardial staging is used during open heart surgery if a surgical procedure creates an atrio-ventricular block. The electrodes are placed in contact with the outer wall of the ventricle (epicardium) to maintain a satisfactory cardiac output until a transcutaneous transect electrode has been inserted.
Moving speed (temporary)
The transvenous channel, when used for temporary tempo, is an alternative to transcutaneous travel. The pacemaker wire is placed into a blood vessel, under sterile conditions, and then forwarded to the right atrium or right ventricle. The pacing cable is then connected to an external pacemaker outside the body. Transvenous pacemaker is often used as a bridge for permanent pacemaker placement. These can be stored in place until a permanent pacemaker is implanted or until there is no longer a pacemaker requirement and then removed.
The subklavicular spur
Permanent pacing with implantable pacemakers involves the transvenous placement of one or more pacing electrodes in space, or chambers, of the heart, while the pacemaker is implanted in the skin beneath the clavicle. This procedure is performed with a suitable vein incision where the lead electrode is inserted and passes through the blood vessels, through the heart valve, until positioned in the chamber. This procedure is facilitated by fluoroscopy that allows the doctor to see the passage of lead electrodes. After satisfactory completion of the electrode is confirmed, the opposite end of the electrode tip is connected to the pacemaker generator.
There are three basic types of permanent pacemaker, classified according to the number of rooms involved and their basic operating mechanism:
- One-room pacemaker . In this type, only one lead pacing is placed into the heart chamber, either the atrium or the ventricle.
- Double chamber pacemaker . Here, the wires are placed in two heart chambers. One end of the step towards the atrium and one step into the ventricle. This type more closely resembles the heart's natural pacemaker by helping the heart function in coordination between atria and ventricle.
- Level-responsive pacemaker . This pacemaker has sensors that detect changes in the patient's physical activity and automatically adjusts the pacing rate to meet the metabolic needs of the body.
Maps Artificial cardiac pacemaker
Basic functions
Modern pacemakers usually have many functions. The most basic form monitors the heart's original heart rhythm. When a pacemaker does not detect a heartbeat for a normal length of time, it stimulates the heart's ventricle with a short, low-voltage pulse. This sensing and stimulating activity continues with a beat-based beat.
More complex forms include the ability to sense and/or stimulate both atrial and ventricular space.
From here, the basic on demand "motion mode is VVI or by automatic rate adjustment for VVIR exercises - this mode is suitable when there is no synchronization with the required atrial pulse, as in atrial fibrillation. Equal atrial pacing mode is AAI or AAIR which is the mode of choice when atrioventricular conduction is intact but the natural pacemaker of the sinoatrial node is unreliable - sinus node disease (SND) or sinus syndrome pain. Where the problem is the atrioventricular block (AVB) the pacemaker is needed to detect atrial pulses and after a normal delay (0.1-0.2 seconds) triggers the ventricular pulse, unless it has occurred - this is the VDD mode and can be achieved by leading single pacing with electrodes in the right atrium (for sensing) and ventricle (for feel and speed). This mode of AAIR and VDD is unusual in the US but is widely used in Latin America and Europe. DDDR mode is most commonly used because it includes all options although pacemakers require separate and more complex atrial and ventricular directions, requiring careful programming of its function for optimal results.
Biventricular staging
Cardiac resynchronization therapy (CRT) is used for people with heart failure in whom the left and right ventricle do not contract simultaneously (ventricular dysyynchrony), which occurs in about 25-50% of patients with heart failure. To achieve CRT, a biventricular pacemaker (BVP) is used, which can move the left ventricular septum and lateral wall. By pacing both sides of the left ventricle, pacemakers can synchronize the ventricular contractions.
The CRT device has at least two clues, one passes through the cava vein and the right atrium to the right ventricle to stimulate the septum, and the other passes through the cava vein and the right atrium and is inserted through the coronary sinus to moving the left ventricular epicardus wall. Often, for patients with normal sinus rhythm, there is also tin in the right atrium to facilitate sync with atrial contraction. Thus, the time between atrial and ventricular contractions, as well as between the septal and lateral walls of the left ventricle can be adjusted to achieve optimal heart function.
CRT devices have been shown to reduce mortality and improve quality of life in patients with symptoms of heart failure; the LV ejection fraction is less than or equal to 35% and the duration of QRS in 120 ms or greater EKG.
Biventricular pacing itself is referred to as CRT-P (for pacing). For certain patients at risk for arrhythmias, CRTs can be combined with a cardioverter-defibrillator implant (ICD): the device, known as CRT-D (for defibrillation), also provides effective protection against life-threatening arrhythmias.
Progress in function
A major step forward in pacemaker function is to try to mimic properties by utilizing various inputs to produce a responsive pacemaker that uses parameters such as QT interval, pO 2 - pCO 2 ( dissolved oxygen or carbon dioxide levels) in the arterial system, physical activity determined by the accelerometer, body temperature, ATP levels, adrenaline, etc. Instead of producing a predetermined static heartbeat, or intermittent control, such as a pacemaker, the 'Dynamic Pacemaker', can compensate for the actual breathing load and potentially anticipated breathing load. The first dynamic pacemaker was discovered by Anthony Rickards of National Heart Hospital, London, England, in 1982.
Dynamic device-making technology can also be applied to artificial hearts in the future. Advances in transitional tissue welding will support this and other organ/joint/artificial joint replacement efforts. Stem cells may be interesting in transitional tissue welding.
Much progress has been made to improve the control of pacemakers ever implanted. Much of this has been made possible by the transition to pacemaker-controlled microprocessors. Pacemakers that control not only the ventricles but the atria have also become common. Pacemakers that control both atria and ventricle are called dual-chamber pacemakers. Although the dual-chamber model is usually more expensive, setting the atria contraction to precede the ventricle improves the efficiency of cardiac pumping and can be useful in congestive heart failure.
The responsive speed rate allows the device to sense the patient's physical activity and respond appropriately by increasing or decreasing the base pacing rate through the response rate algorithm.
The DAVID trial has demonstrated that no need to step from the right ventricle may aggravate heart failure and increase the incidence of atrial fibrillation. The newer dual chamber devices can keep the number of right ventricular chambers to a minimum and thus prevent the worsening of heart disease.
Considerations
Insertion
Pacemakers are usually admitted to the patient through simple surgery using local anesthesia or general anesthesia. Patients may be given medication for relaxation before surgery as well. Antibiotics are usually given to prevent infection. In most cases, a pacemaker is inserted in the area of ​​the left shoulder, where an incision is made beneath the collarbone, creating a small pocket in which the pacemaker is actually stored in the patient's body. Lead or lead (the number of leads varies depending on the type of pacemaker) is inserted into the heart through a large vein using a fluoroscope to monitor the progress of lead insertion. The right ventricular leader is positioned away from the right ventricular (tip) tip and rises in the interventricular septum, below the outlet, to prevent deterioration of the heart's strength. The actual operation usually lasts 30 to 90 minutes.
After surgery, the patient should be careful with wounds while healing. There is a follow-up session where pacemakers are checked using a "programmer" who can communicate with the device and allow a health care professional to evaluate system integrity and define settings such as pacing voltage output. Patients should have their cardiac powers frequently analyzed by echocardiography, every 1 or 2 years, to ensure that placement from the right ventricular end does not cause weakening of the left ventricle.
Patients may want to consider some basic preparations before surgery. The most basic preparation is that people who have body hair on the chest may want to remove hair with clippings just before surgery or use a hair removal medication (pre-surgery shaving has decreased as it can cause skin damage and increase the risk of infection every surgical procedure) because surgery will involving bandages and monitoring equipment to be attached to the body.
Because pacemakers use batteries, the device itself will need to be replaced as the battery loses power. Device replacement is usually a simpler procedure than the original insertion because it usually does not require a clue to be embedded. A typical replacement requires an operation where an incision is made to remove an existing device, lead is removed from an existing device, leads are connected to a new device, and new devices are inserted into the patient's body, replacing the previous one. tool.
Pacemaker patient identification card
Card identification card pacemaker carries information such as patient data (among others, primary symptoms, ECG, cause), pacemaker (physician, hospital), IPG (rate, mode, implantation, producer, type) and lead.
Periodic pacemaker check
Once the pacemaker is implanted, it is periodically checked to ensure the device is operating and performing appropriately. Depending on the frequency set by the following doctors, the device can be checked as often as necessary. Routine pacemaker checkups are usually performed at the office every six (6) months, though will vary depending on the patient/device status and the availability of remote monitoring.
At the time of follow-up office, the device will be interrogated for a diagnostic test. These tests include:
- Sensing: the ability of the device to "see" intrinsic cardiac activity (Atrial and ventricular depolarization).
- Impedance: A test for measuring the integrity of lead. A large and/or abrupt increase in impedance can be an indication of tin fracture when a large and/or abrupt impedance decrease may indicate a violation of lead insulation.
- Threshold: this test confirms the minimum amount of energy (both volts and pulse widths) required to depolarize reliably (capturing) the space under test.
Because modern pacemakers are "on demand", which means that they only race when needed, the device's life is affected by how much its use. Other factors that affect the device's longevity include programmed output and algorithms (features) that cause higher current rates to flow from the battery.
An additional aspect of checking in the office is to check every event that has been stored since the last follow-up. These are usually stored according to the specific criteria set by the doctor and specifically for the patient. Some devices have the availability to display the program's electro intracardiac from the start of the event as well as the event itself. This is helpful in diagnosing the cause or origin of the event and making the necessary programming changes.
Magnetic field, MRI, and other lifestyle issues
The patient's lifestyle is usually not modified to a high level after entering a pacemaker. There are some unwise activities like full contact sports and activities that involve strong magnetic fields.
Pacemaker patients may find that some types of everyday actions need to be modified. For example, a shoulder belt from a vehicle seat belt may be uncomfortable if the harness has to fall in the pacemaker.
Any type of activity involving a strong magnetic field should be avoided. This includes activities such as possible arc welding, with certain types of equipment, or maintaining machines that can produce intense magnetic fields (such as magnetic resonance imaging machines (MRIs)).
However, in February 2011 the FDA approved a new pacemaker from Medtronic called Revo MRI SureScan which was first labeled as conditional for MRI use. There are some limitations to its use including the qualification and setting of a particular patient scan. Most major cardiac device manufacturers now have FDA approved MR conditional pacemakers.
A 2008 US study has found that magnets in some of the headphones supplied with a portable music player, when placed in an inch of pacemaker, can cause interference.
Some medical procedures may require the use of antibiotics to be administered prior to the procedure. The patient should notify all medical personnel that he or she has a pacemaker. Some standard medical procedures such as the use of MRI can be ruled out by patients who have pacemakers.
In addition, according to the American Heart Association, some home devices have far-reaching potential for interference by occasionally hampering a tap. Mobile phones available in the United States (less than 3 watts) do not appear to damage the pulse generator or affect how pacemakers work.
Turning off the pacemaker
A panel of The Heart Rhythm Society, a Washington-based specialist organization, DC, found that it is legal and ethical to meet patient demand, or by those with the legal authority to make decisions for patients, to disable implanted heart devices. Lawyers say that the legal situation is similar to removing the food hose, although there is currently no legal precedent involving pacemakers in the United States. A patient in the United States is deemed to have the right to refuse or stop treatment, including a pacemaker that keeps him alive. Doctors have the right to refuse to turn it off, but it is recommended by the HRS panel that they should refer the patient to the doctor who will. Some patients believe that desperate and debilitating conditions, such as those caused by severe strokes or late-stage dementia, can cause so much suffering that they prefer not to prolong their life by supporting measures, such as heart devices.
Privacy and security
Security and privacy issues have been upgraded with pacemakers that allow wireless communication. An unauthorized third party may be able to read the patient's note contained in the pacemaker, or reprogram the device, as the research team has indicated. Demonstrations work in close proximity; they do not try to develop the antenna remotely. Proof of concept utilization helps point to the need for better security and reminder steps of patients in remote accessible medical implants. In response to this threat, Purdue University and Princeton University researchers have developed a prototype firewall device, called MedMon, designed to protect wireless medical devices such as pacemakers and insulin pumps from attackers.
Complications
Complications from surgery to implant a pacemaker are rare, but may include: Infection in which pacemakers are planted. Allergic reactions to dyes or anesthetics used during the procedure. Swelling, bruising or bleeding on the generator site, especially if the patient takes blood thinners.
Possible complications of dual-chamber pacemakers are 'tachycardia mediator-mediated' (PMT), a form of reentrant tachycardia. In PMT, a pacemaker forms an anterograde (atrium to ventricle) the extremity of the circuit and the atrioventricular (AV) node forms a retrograde (ventricular to atrial) branch of the circuit. PMT treatment usually involves pacemaker reprogramming.
Another possible complication is "pacemaker tracked tachycardia," in which supraventricular tachycardia is traced by a pacemaker and produces a pulse of ventricular tin. This becomes very rare because newer devices are often programmed to recognize supraventricular tachycardia and switch to non-tracking mode.
Sometimes the clue, which is a small diameter wire, from the pacemaker to the implantation site in the heart muscle needs to be removed. The most common reason for tin removal is infection, but over time lead may decrease for a number of reasons such as tin flexing. Changes to pacemaker programming can overcome lead degradation to some extent. However, a patient who has multiple pacemaker replacements for a decade or two in which the instructions are reused may require a lead replacement operation.
Lead replacement can be done in one of two ways. Insert a new set of instructions without removing the flow instructions (not recommended because it gives extra obstruction to the bloodstream and heart valve function) or remove current instructions and then enter a replacement. The technique of removal of lead will vary depending on the surgeon's estimate of the probability that simple traction will be sufficient for more complex procedures. The leads can usually be disconnected from pacemaker easily which is why the replacement of a device usually requires a simple operation to access the device and replace it by simply removing the hook from the device to replace and hook leads to the new device. Possible complications, such as cardiac wall perforations, originate from removing lead from the patient's body.
The other end of the pacemaker is actually implanted into the heart muscle. In addition, clues that have been implanted for a decade or two will usually have attachments to the patient's body in various places on the path from the device to the heart muscle because the human body tends to insert foreign devices into the network. In some cases such as devices that have been inserted for a short time, removal may involve simple traction to pull lead from the body. Removal in other cases is usually done with threaded cutting tools on tin and transferred to tin to remove all organic attachments with small cutting lasers or similar devices.
Pacemaker causes malposition in various locations has been described in the literature. Depending on the location of incandescent and the treatment of symptoms varies.
Another complication that might be called the twiddler syndrome occurs when a patient manipulates a pacemaker and causes the lead to be removed from the targeted location and causes possible stimulation from other nerves.
Other devices
Sometimes pacemaker-like devices, called implantable cardioverter-defibrillators (ICDs) are planted. These tools are often used in the care of patients at risk from sudden cardiac death. ICDs have the ability to treat various types of heart rhythm disturbances by pacing, cardioversion, or defibrillation. Some ICD devices can distinguish between ventricular and ventricular tachycardia (VT) fibrillation, and may attempt to move the heart faster than its intrinsic rate in the case of VT, to try to break the tachycardia before progressing to ventricular fibrillation. This is known as fast-pacing, overdrive temp, or anti-tachycardia pacing. ATP is only effective if the underlying rhythm is ventricular tachycardia, and is never effective if rhythm is ventricular fibrillation.
History
Origin
In 1889, John Alexander MacWilliam reported in the British Medical Journal (BMJ) of his experiments in which the application of electrical impulses to the human heart in asystole causes ventricular contraction and heart rhythm of 60-70 beats per minute can be induced by impulses which is applied at a distance equal to 60-70/min.
In 1926, Mark C Lidwill of Royal Prince Alfred Hospital in Sydney, supported by physicist Edgar H. Booth of the University of Sydney, designed a portable device that was "pinned to the point of lighting" and where "One pole was applied to a soaked skin pad in a strong salt solution "while the other pole" consists of an isolated needle except at its point, and falls into the corresponding heart chamber ". "Pacemak rates vary from about 80 to 120 pulses per minute, as well as variable voltages from 1.5 to 120 volts". In 1928, the equipment was used to revive the stillborn infant at Crown Street Women's Hospital, Sydney whose heart kept beating "by itself", "at the end of 10 minutes" of stimulation.
In 1932, the American physiologist Albert Hyman, with the help of his brother, described his own electro-mechanical device, powered by a spring-handed hand-motor. Hyman himself referred to his invention as a "pacemaker", a term that continues to be used to this day.
The apparent disappearance in research publications conducted between the early 1930s and World War II can be attributed to the pervasive public perception of nature by "reviving the dead". For example, "Hyman does not publish data about the use of a pacemaker in humans because of adverse publicity, both among physicians, and because of newspaper reports at the time, Lidwell may have known this and did not continue with experiments on humans."
Wearable
In 1958, engineer Earl Bakken from Minneapolis, Minnesota, produced the first wearable external pacemaker for patients C. Walton Lillehei. This transistorized pacemaker, housed in a small plastic box, has controls to allow adjustment of the pacemaker's heart and output voltage and is connected to an electrode that passes through the patient's skin to terminate the electrode attached to the surface of the myocardium. heart.
One of the earliest patients receiving this Lucas pacemaker was a woman in her early 30s in an operation performed in 1964 at Radcliffe Infirmary in Oxford by cardiac surgeon Alf Gunning of South Africa and then Professor Gunning who was a student of Christiaan Barnard.. This pioneering operation was undertaken under the guidance of heart consultant Peter Sleight at Radcliffe Infirmary at Oxford and his cardiac research team at St George's Hospital in London. Sleight later became Professor of Cardiovascular Medicine at the University of Oxford.
Implantable
The first clinical implant into human implantable pacemaker was in 1958 at the Karolinska Institute in Solna, Sweden, using a pacemaker designed by Rune Elmqvist and the surgeon ÃÆ'... to Senning, connected to the electrodes attached to the cardiac myocardium with thoracotomy.. The device failed after three hours. The second device is then implanted which lasts for two days. The patient of the world's first implantable pacemaker Arne Larsson received 26 different pacemakers during her lifetime. He died in 2001, at the age of 86, living longer than the inventor and surgeon.
In 1959, transvenous pacing was temporarily first demonstrated by Seymore Furman and John Schwedel, in which catheter electrodes were inserted through the basilic vein of the patient.
In February 1960, an improved version of the Swedish Elmqvist design was implanted in Montevideo, Uruguay at Casmu 1 Hospital by Doctors Orestes Fiandra and Roberto Rubio. The device survived until the patient died of another illness, nine months later. Swedish early designed devices use rechargeable batteries, which are filled by induced coils from the outside. It was the first pacemaker planted in America.
Implanted pacemakers built by Wilson Greatbatch engineers began to be used in humans beginning April 1960 after extensive animal testing. Vestal Innovation varies from previous Swedish devices in using primary cells (mercury batteries) as an energy source. The first patient stayed for 18 months further.
The first use of transvenus pacing in conjunction with implanted pacemakers was by Parsonnet in the United States, Lagergren in Sweden and Jean-Jacques Welti in France in 1962-63. The transvenous, or pervenous, procedure involves a vein incision inserted into a catheter electrode under fluoroscopic guidance, until it is inserted into the right ventricular trabeculae. This method became the method of choice in the mid-1960s.
Cardiothoracic Surgeon Leon Abrams, and Medical Engineer Ray Lightwood, developed and implanted the patient's first patient-controlled, first-rate pacemaker in 1960 at the University of Birmingham. The first implant occurred in March 1960, with two further implants the following month. All three of these patients make good recovery and return to high quality of life. In 1966, 56 patients had undergone implantation with one who survived for more than 5 Ã, 1 / 2 year.
Lithium battery
Previous implant devices all suffer from unreliable and short lifespan of primary cell technology available primarily from mercury batteries. In the late 1960s, several companies, including ARCO in the US, developed an isotope-powered pacemaker, but this development was surpassed by a development in 1971 from lithium iodide cells by Muffy Vestal. Lithium-iodide or lithium anode cells are becoming the standard for future pacemaker design.
A further constraint to initial device reliability is the diffusion of water vapor from body fluids through the encapsulation of epoxy resins that affect electronic circuits. This phenomenon was overcome by wrapping pacemaker generators in a sealed metal case, originally by Telectronics of Australia in 1969 followed by Cardiac Pacemakers Inc. of Minneapolis in 1972. This technology, using titanium as metal encasing, became standardized by the 1970s.
On July 9, 1974, Manuel A. VillafaÃÆ' Â ± a and Anthony Adducci founder of Cardicac Pacemakers, Inc. (Guide) at St. Paul, Minnesota, manufactures the world's first pacemaker with lithium anode and lithium-iodide electrolyte solid-state batteries.
Other people who contributed significantly to the development of pacemaker technology in the pioneering years were Bob Anderson of Medtronic Minneapolis, JG (Geoffrey) Davies of St George's Hospital London, Barouh Berkovits and Sheldon Thaler of American Optical, Geoffrey Wickham of Telectronics Australia , Walter Keller of Cordis Corp. of Miami, Hans Thornander who joined the Rune Elmquist previously mentioned in Elema-Schonander in Sweden, Janwillem van den Berg of the Netherlands and Anthony Adducci of Cardiac Pacemakers Inc.
Intra-cardial
By 2013, some companies announce devices that can be inserted through a leg catheter rather than an invasive operation. The device is roughly the size and shape of a pill, much smaller than the size of a traditional pacemaker. Once implanted, the device will contact the muscles and stabilize the heart rate. Engineers and scientists are currently working on this type of device. In November 2014 a patient, Bill Pike of Fairbanks, Alaska, received a Medtronic Micra pacemaker at Providence St Vincent Hospital in Portland Oregon. D. Randolph Jones is an EP doctor. By 2014 also St. Jude Medical Inc. announced the first enrollment in the Unpublished Pacemaker Observation Study that evaluated the technology without a foothold of Nanostim. The Nanostim pacemaker receives CE marking in 2013. The post-approval implant has taken place in Europe. European studies have recently been discontinued, after reports of six perforations causing two patient deaths. After the investigation, St. Jude Medical resumed the study. But in the United States this therapy is still not approved by the FDA. While St. Jude Nanostim and Medtronic Micra are only single-chamber pacemakers, it is estimated that no two-way dual pacing for patients with atrioventricular blocks would be possible with further developments.
See also
- Biological propulsion
- Button cell
- Cardiac conduction system of the heart
- Implantable cardioverter-defibrillator
- Infective endocarditis
- Pacemaker syndrome
- WiTricity
- Qi (inductive power standard)
References
External links
- Detect and Distinguish Cardiac Pacing Artifacts
- Implantable Cardioverter Defibrillator from National Heart, Lung and Blood Institute
- Biventricular Pacemaker: What is Heart Resynchronization Therapy? Podcast from the Medical University of South Carolina
- Current indications for CRT-P and CRT-D: Webinars from the European Heart Rhythm Association (EHRA)
Source of the article : Wikipedia
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