What Is an Implantable Pacemaker?

Pacemaker implantation refers to a method of artificially implanting a pacemaker, using a specific frequency pulse current to stimulate the heart through a lead and an electrode, instead of the pacemaker of the heart to drive the heartbeat. It is a treatment for irreversible heartbeat Safe and effective method of pulse conduction dysfunction, especially for the treatment of severe chronic arrhythmias.

Pacemaker implantation

A cardiac pacemaker is an electronic therapeutic device implanted in the body. It sends out electrical pulses powered by a battery through a pulse generator. It stimulates the heart muscle contacted by the electrode through the conduction of a wire electrode and excites and contracts the heart. , So as to achieve the purpose of treating cardiac dysfunction caused by some arrhythmia. Since the first cardiac pacemaker was implanted into the human body in 1958, the pacemaker manufacturing technology and process have developed rapidly and the functions have become increasingly perfect. While the pacemaker was successfully used to treat bradyarrhythmias and saved thousands of patients' lives, pacemakers have also begun to be applied to tachyarrhythmias and non-ECG diseases, such as the prevention of paroxysmal atrial tachycardia. Arrhythmia, carotid sinus syncope, dual-chamber simultaneous medication refractory congestive heart failure, etc.

Development of implantable pacemakers

In 1791 Galvani experimentally proved the existence of bioelectricity, and found that muscles have a contractile response to electrical stimulation. In 1882 Ziemssen discovered that electrical stimulation can cause cardiac contraction. Early experimental research and clinical observations are of great significance to the later invention and application of cardiac pacing technology. At the academic conference held in Sydney, Australia, in September 1929, Lidwill first reported the successful use of his invented portable pacing device to save a baby with cardiac arrest. This is the first time that artificial heart pacing technology has been used clinically [1].

In 1932, Hyman designed and produced an electric pulse generator driven by a clockwork. The net weight of the device was 7.2 kg. The pulse frequency could be adjusted to 30, 60, 120 beats per minute. Hyman called it an artificial cardiac pacemaker. artificial cardiac pacemaker ", this clockwork pulse generator became the first artificial cardiac pacemaker in human beings.

In January 1952, Dr. Paul M. Zoll, a doctor of Harvard Medical School in the United States, applied an electric pulse with a pulse width of 2 ms and an intensity of 75 to 150 V on the surface of the human chest wall for the first time to successfully perform cardiac resuscitation for a patient with cardiac arrest. Saved the life of the dying patient. Because the electrodes are sewn on the chest wall, the electrical stimulation stimulates the heart and also stimulates the chest muscles, causing local muscle twitches and pain. However, this initiative immediately attracted widespread attention from the medical and engineering communities, and welcomed cardiology In another period of change, temporary pacemaker surgery has gradually been widely accepted by the medical community, and has become a conventional treatment method for bradycardia. Paul M. Zoll is known as the "Father of Pacing".

In 1952, Dr. Senning and Elmqvist engineers in Sweden developed the first implantable cardiac pacemaker. On October 8, 1958, Senning implanted a pacemaker into a patient with viral myocarditis and complete atrioventricular block for the first time. This person became the first patient in the world to be implanted with a pacemaker.

Development of pacemaker technology

Earlier pacemakers had many problems that limited their widespread clinical use, such as the need to open the chest to implant the pacing lead electrode, the pacing threshold quickly increased, the lead was easily broken and displaced, the battery life was short and the stability was poor. In order to solve the above problems, many scholars and engineers have made unremitting research. In 1962, transvenous leads were used in the clinic, and implantation of pacemakers did not require thoracotomy. In 1964, the R-wave suppressor (VVI) pacemaker appeared, which avoided the severe ventricular arrhythmia that might be caused by the unsynchronization of the fixed-frequency pacemaker. The first dual-chamber pacemaker was implanted in 1978. Since the 1980s, due to the rapid development of electronic technology and sensor technology and the widespread application of microprocessors, the function of pacemakers has become more and more perfect, and frequency-adaptive pacing, in vitro extraction of pacing parameters, and program-controlled, pacing appear. The device monitors and records arrhythmic events and pacemaker working conditions, and can automatically adjust pacing parameters within a certain range according to the different conditions of the patient, making the pacemaker better suitable for complex clinical situations and different Patient.

While pacemakers were successfully used to treat bradycardia, pacemakers also began to be applied to non-bradycardia conditions. In the 1970s, anti-tachycardia pacemakers were used to treat supraventricular tachycardia. This technique is still used in implantable cardioverter defibrillators (ICDs). In 1995, Bakker et al. Confirmed the hemodynamic benefits of biventricular pacing. For severe heart failure with indoor block, especially left bundle branch block, biventricular pacing can resynchronize ventricular contractions and improve cardiac function. Increased activity tolerance and quality of life. Currently, this cardiac resynchronization therapy (CRT) has been approved by the US FDA. In short, more than 40 years have witnessed rapid development in both pacemaker engineering and clinical applications. Statistics on the use of pacemakers around the world were calculated in 1997, calculated as the number of pacemakers implanted per million people, of which the United States 571, France 552, Germany 440, Canada 368, Australia 345, Israel 293, Japan 153, Hong Kong 100, Singapore 61.

Development of implantable pacemakers in China

In October 1962, the first artificial cardiac pacemaker (transeppericardial pacing therapy) was installed in the Department of Cardiology and Cardiac Surgeon of Shanghai First People's Hospital. The first transvenous pacemaker was successfully implanted in China in 1973, and has developed considerably over the decades. The data from the National Pacemaker Use Survey conducted by the Cardiac Electrophysiology and Pacemaker Branch of the Chinese Medical Association in 2002 showed that at least 279 hospitals in mainland China have performed pacemaker implantation. A total of 10,857 pacemakers were implanted in 2001. 8 per million people. Among them, double-chamber pacemakers accounted for 36.3%, ventricular single-chamber pacemakers accounted for 56.2%, and the others including AAI (R) and VVI (R) accounted for 7.5%.

The pulse generator periodically issues a pulsed current of a certain frequency, which is transmitted to the myocardium (atrial or ventricle) contacted by the electrode through the lead and the electrode, so that local myocardial cells are stimulated by external electrical stimulation and are connected or gapped through the gap between the cells. The connection conducts to the surrounding myocardium, causing the entire atrium or ventricle to excite and in turn produce contractile activity. It needs to be emphasized that the myocardium must have the functions of excitation, conduction and contraction, and the cardiac pacing can play its role.

Artificial cardiac pacing system mainly includes two parts: pulse generator and electrode lead. Pulse generators are often referred to as pacemakers alone. In addition to the pacing function described above, the pacing system also has the sensing function of transmitting the heart's own ECG back to the pulse generator.

The pacemaker is mainly composed of a power source (that is, a battery, and now mainly uses a lithium-iodine battery) and an electronic circuit process, which can generate and output electrical pulses.

The electrode lead is a conductive metal wire wrapped with an insulating layer, and its function is to transmit the electrical pulses of the pacemaker to the heart and transmit the intracardiac electrocardiogram to the pacemaker's sensing circuit.

Pacemaker code

In 1987, the North American Society of Cardiac Pacemaker Electrophysiology (NASPE) / British Pacemaker and Electrophysiology Group (BPEG) developed a five-letter code pacemaker named by the International Committee of Cardiology (ICHD) in 1981. NBG code (Figure 1).

Figure 1: Five-digit code name for NBG pacemaker

Single-chamber pacing

1. AAI mode The working mode of this mode is atrial pacing, atrial sensation, which inhibits the issuance of pacemaker pulses after sensing the atrial's own electrical activity. In this mode, ventricular signals are not perceived.

2. VVI mode The working mode of this mode is ventricular pacing and ventricular sensing. It suppresses the issuance of pacemaker pulses after sensing the electrical activity of the ventricle. It is also called R-wave suppression ventricular pacing or ventricular on-demand pacing. In this mode, the atrial signal is not perceived. VVI only pulses the ventricular pacing ventricle when it is "needed". The rhythm produced by pacing is actually an escape rhythm.

3.Other single-chamber pacing modes

(1) AOO, VOO mode: Asynchronous pacing mode, also known as fixed-frequency pacing. The atrium and ventricle only have pacing and no sensory function. The pacemaker periodically sends pulses to stimulate the atrial (AOO) or ventricle (VOO) at a fixed frequency (asynchronous). The pulses are issued regardless of the speed of the heart rate.

(2) ATT, VTT mode: Atrial and ventricular triggering pacing mode. The atrium and ventricle both have pacing and sensing functions, but the response after sensing their own atrial and ventricular electrical activity is to trigger (T) the release of atrial and ventricular pulses (rather than inhibit). The disadvantage is power consumption. Nor is it applied as a separate pacemaker mode.

Double-chamber pacing

1. DDD mode, also known as atrioventricular all-around pacing, is a physiological pacing mode with atrioventricular dual-chamber sequential pacing, dual atrial ventricular dual perception, triggering and inhibiting dual responses.

2. VDD mode is also called atrial-synchronized ventricular suppression pacemaker. The atrium and ventricle have sensing functions, but only the ventricles have pacing functions. In the entire VDD pacing system, the correct perception of P waves is the key to its normal operation.

3. The atrial and ventricle in the DDI mode both have sensing and pacing functions. After P wave sensing, the atrial pacing is suppressed (similar to DDD), but the atrioventricular interval is not triggered, that is, no ventricular tracking occurs. If the patient has normal atrioventricular conduction, it is basically similar to AAI; if the patient has atrioventricular block, the atrioventricular synchronization can be achieved during atrial pacing, and the atrioventricular synchronization cannot be achieved during atrial perception. Therefore, the length of the atrioventricular delay after atrial activity varies. This pacing mode is characterized by atrioventricular synchronization during atrial pacing, and atrioventricular synchronization during atrial consciousness. It is not used as a separate pacing mode, but only as a mode of operation after a DDD (R) mode change.

Pacemaker automation and frequency adaptive pacing

Pacemaker automation

After the pacemaker is implanted, it can automatically record and search the patient's heart rhythm and pacemaker working status, and then synthesize, summarize, and analyze these big data. After making a judgment, it can automatically adjust the pacing parameters to meet the needs of the patient. Human intervention. Of course, these automated functions also require manual follow-up to determine the correctness of the way they work.

The automatic functions of current pacemakers include: automatic conversion of pacing mode, automatic adjustment of atrioventricular delay, automatic mode conversion, pacemaker-mediated tachycardia function, automatic adjustment of sensory sensitivity, automatic adjustment of pacing frequency, Automatic pacing output voltage adjustment.

Frequency adaptive pacing

During extreme or sub-extreme exercise, the increase in cardiac output depends mainly on the increase in heart rate, especially in the elderly or patients with cardiac insufficiency (decreased systolic function reserve). The frequency adaptive pacemaker can automatically adjust the pacing frequency by sensing body movement and blood pH to determine the body's need for cardiac output, and accordingly increase or decrease the pacing frequency, thereby improving the exercise tolerance of patients with cardiac dysfunction.

Frequency adaptive pacing indications are mainly cardiac dysfunction. It is generally believed that after exercise, the heart rate cannot increase, or the increase is not obvious, and 85% of the predicted maximum heart rate (maximum heart rate = 220-age) cannot be defined as time-varying dysfunction (the fastest heart rate during exercise "120bpm is mild change Insufficient functions, "100bpm is severely incomplete."

Sinus insufficiency and chronic atrial fibrillation combined with a significantly slow ventricular rate are the main indications for frequency-adaptive pacing. However, if the symptoms such as palpitations worsen after the heart rate increases, or the symptoms of heart failure and angina are aggravated, it is not appropriate to use a frequency adaptive pacemaker.

Choosing a pacemaker for a particular patient is a problem that clinicians often face. The principles are as follows:

1. If you have chronic persistent atrial fibrillation or atrial quiescence, choose VVI (R).

2. For those with sinus node dysfunction, if there is no atrioventricular block or if it is predicted that the recent probability of atrioventricular block is very low, choose AAI (R), otherwise choose DDD (R).

3. Atrioventricular block

There is persistent atrial tachyarrhythmia, choose VVI (R);

Sick sinus syndrome exists, choose DDD (R);

The sinus node function is normal or the probability of sinus node insufficiency is expected to be low. VDD or DDD can be selected.

Single ventricular pacing is no longer recommended, and dual-chamber pacing increases survival-adjusted quality of life at generally accepted prices. As for the choice of implantation of AAI or DDD pacemaker, although DDD is more expensive, it should be considered that patients may develop AV block.

In addition, comprehensive consideration needs to be given to the patient's age, heart disease and associated diseases, economic status, and the general condition of the patient.

Temporary cardiac pacing

There are five methods, including percutaneous pacing, transesophageal pacing, transthoracic puncture, open chest epicardial pacing, and transvenous pacing. At present, the latter is more selected.

Femoral veins, subclavian veins, or internal jugular veins are commonly used for temporary pacing electrode leads. Electrode lead displacement is more common than permanent cardiac pacing. Postoperative ECG monitoring should be strengthened, including early rise in pacing threshold, changes in sensory sensitivity, and electrode lead dislocation, especially for pacemaker-dependent persons. In addition, because the electrode leads communicate with the outside world through the puncture point, care should be taken to clean locally to avoid infection, especially for longer periods of time. In addition, the patient should remain supine after temporary pacing via the femoral vein, and the lower extremity is braked on the venipuncture side.

Permanent cardiac pacing

The vast majority of endocardial electrode leads are currently used. Technical highlights include venous selection, lead electrode fixation, and implantation of pacemakers.

1. Vein selection The commonly used veins for electrode lead insertion are: superficial veins include cephalic vein, external jugular vein, deep veins include subclavian vein, axillary vein internal jugular vein. Usually, the contralateral cephalic vein or subclavian vein is preferred. If it is unsuccessful, the internal or external jugular vein is selected.

2. Placement of the electrode wire According to the needs, the electrode wire is placed in the cardiac cavity that needs pacing. Generally, passive fixation is used, and active electrode fixation can also be used.

3. Implantation of pacemaker The pacemaker is usually buried under the skin of the chest on the same side of the electrode lead. Connect the electrode lead to the pulse generator, and place the extra lead near the muscle surface and the pacemaker near the skin into the subcutaneous bag.

In short, the method is to insert an electrode lead from a vein under the arm or clavicle, and insert it into a predetermined cardiac pacing position under X-ray fluoroscopy, fix and detect it. Then a pacemaker connected to the electrode lead is embedded in the chest, the skin is sutured, and the operation can be completed.

Artificial heart pacing is divided into temporary and permanent, and they have different indications.

Indications for temporary cardiac pacing

Temporary cardiac pacing is a temporary or temporary artificial cardiac pacing that is not permanently implanted with a pacing electrode lead. The pacing electrode lead is generally placed for no more than 2 weeks. The pacemaker is placed outside the body. After the purpose of diagnosis, treatment and prevention is reached, the pacing electrode lead is removed. If you still need to continue pacing treatment, you should consider placing a permanent pacemaker.

Any patient with bradycardia that is symptomatic or causes hemodynamic changes is the object of temporary cardiac pacing. The purpose of temporary cardiac pacing is usually divided into treatment, diagnosis, and prevention.

1.Treatment

(1) Onset of A-S syndrome: atrioventricular block, sinus node failure due to various causes (acute myocardial infarction, acute myocarditis, poisoning caused by digitalis or antiarrhythmic drugs, electrolyte disorders, etc.) The resulting cardiac arrest and the onset of Alzheimer's syndrome are absolute indications of emergency temporary cardiac pacing.

(2) Transition of patients with unstable arrhythmia before placement of a permanent pacemaker.

(3) Third-degree atrioventricular block caused by open heart surgery.

(4) Bradycardia and / or persistent ventricular tachycardia induced by bradycardia ineffective with medication.

2 Diagnostics as an aid to some clinical diagnosis and electrophysiological examinations. For example, judge: sinus node function; atrioventricular node function; type of pre-excitation syndrome; reentrant arrhythmia; the effect of antiarrhythmic drugs.

3. Prevention

(1) High-risk patients with significant bradycardia are expected. Some patients with acute myocardial infarction and some slow arrhythmias and cardiac conduction system insufficiency are planning to undergo major surgery and interventional cardiac surgery, and suspected sinus node function. Patients with impaired tachyarrhythmia undergo cardioversion, and patients with preexisting left bundle branch block undergo right-heart catheterization.

(2) Transition of pacemaker-dependent patients when replacing with a new pacemaker.

Indications for permanent cardiac pacing

With the improvement of pacing engineering, the indications for pacing therapy have gradually expanded. The main purpose of implanting a cardiac pacemaker in the early years was to save patients 'lives. Currently, it also includes restoring patients' working ability and quality of life. At present, the main indications can be simply summarized as severe heart diseases such as slow heartbeat, weak heart contraction, and cardiac arrest. In 2012, the American College of Cardiovascular Diseases / American Heart Association / American Heart Rhythm Association re-developed guidelines for implanting pacemakers.

Type I indications include:

Sinus node dysfunction: Symptoms of sinus node dysfunction were recorded, including sinus arrest that often caused symptoms. Symptomatic poor-temporality. Because certain diseases must use certain drugs, and these drugs can cause sinus bradycardia and produce symptoms.

Adult Acquired Atrioventricular Block (AVB):

Grade III AVB and high AVB at any block site with symptomatic bradycardia (including heart failure) or ventricular arrhythmia secondary to AVB.

Long-term use of drugs for treating other arrhythmias or other diseases, which can cause degree AVB and high AVB (regardless of the block site) and symptomatic bradycardia.

Asymptomatic patients with grade III AVB and high AVB at any block site in the awake state were recorded with a cardiac arrest of 3 seconds or longer, or an escape beat heart rate of less than 40 bpm, or an escape beat rhythm point Those below the sinoatrial node.

The level III AVB and high AVB of any block site in the awake state. Asymptomatic atrial fibrillation and bradycardia have one or more long pauses of at least 5 seconds. AVB of any degree III and AVB at any block site after catheter ablation of the AV node.

There is no degree III AVB and high AVB in any block site that may recover after cardiac surgery.

Grade III AVB and high AVB at any block site due to sacral neuromuscular disease, such as tonic muscle dystrophy, Karns-Sayre syndrome, pseudohypertrophic muscular dystrophy, fibula Patients with muscular atrophy.

AV AVB with bradycardia symptoms, regardless of type or block site.

Asymptomatic grade III atrioventricular block at any block site with an average ventricular rate score or "40 beats / min with enlarged heart or left ventricular dysfunction or block below the AV node.

No degree II or III AVB during exercise without myocardial ischemia.

Patients with chronic bifurcation block: accompanied by high AVB or transient III degree AVB. accompanied by type II AVB. Alternative bundle branch block.

Acute myocardial infarction with atrioventricular block:

After ST-segment elevation myocardial infarction, the persistent second-degree AVB of His-Purkinje system combined with alternating bundle branch block or third-degree AVB;

AVB below transient atrioventricular node II or III combined with bundle branch block;

persistent and symptomatic grade II or III AVB.

Carotid sinus allergies and cardiac neurogenic syncope:

Recurrent syncope caused by spontaneous carotid artery stimulation and carotid compression induced ventricular arrest time 3 seconds.

Patients with persistent or symptomatic bradyarrhythmias who have not recovered hope for a heart transplant.

long intermittent dependence of ventricular tachycardia, with or without QT interval prolongation.

Patients with NYHA heart failure who have a left ventricular ejection fraction 35%, complete left bundle branch block and QRS 150ms, sinus rhythm, heart function classification (NYHA) grade , , or active drug therapy CRT or CRT-ICD should be implanted.

The indications for ICD are as follows:

Persistent ventricular tachycardia (VT) with ventricular fibrillation or hemodynamic instability, except for other reversible causes, leading to cardiac arrest;

Patients with organic heart disease and spontaneous persistent VT, regardless of whether the hemodynamic stability is stable;

Have a history of syncope, and electrophysiological examination clearly induced persistent VT or ventricular fibrillation (VF) with hemodynamic instability;

After 40 days of myocardial infarction, the left ventricular ejection fraction is 35%, NYHA or ;

Non-ischemic dilated cardiomyopathy, left ventricular ejection fraction 35%, NYHA or grade;

Left ventricular dysfunction before myocardial infarction, left ventricular ejection fraction 30% after 40 days of myocardial infarction, grade NYHA ;

After myocardial infarction, the left ventricular ejection fraction is 40%, and VF or persistent VT is induced by non-sustained VT or electrophysiological examination.

Type a indications include:

Sinus node dysfunction:

Sinus node dysfunction leads to a heart rate of <40 bpm, there is clear evidence between symptoms and bradycardia, but whether bradycardia is recorded or not.

Patients with unexplained syncope, clinical findings or electrophysiological examination-induced sinus node dysfunction.

Adults with acquired AVB:

Asymptomatic persistent third-degree AVB with a heart rate below 40 bpm without accompanying heart enlargement.

Electrophysiological examination revealed asymptomatic second-degree AVB at or below the level of the His bundle.

AVB of grade or is accompanied by hemodynamic performance similar to pacemaker syndrome.

Asymptomatic type II AVB with narrow QRS wave. However, when the type II AVB is accompanied by a wide QRS wave, including the right bundle branch block, the indication is upgraded to class I.

Patients with chronic bifurcation block:

Although it is not confirmed that syncope is caused by AVB, other causes (especially ventricular tachycardia) can be ruled out.

Although there are no clinical symptoms, the electrophysiological examination revealed that the HV interval was 100ms.

At the time of electrophysiological examination, the non-physiological block of His is induced by atrial pacing.

For patients with recurrent syncope, no exact carotid stimulation event, and high-sensitivity cardiac suppression response ventricular arrest time> 3s, a permanent pacemaker should be considered.

Tachycardia pacing is limited to patients with recurrent supraventricular tachycardia who fail catheter ablation and / or medication failure, or who cannot tolerate the side effects of the medication.

High-risk patients with long QT syndrome.

The following patients with heart failure can be implanted with a CRT or CRTICD:

Left ventricular ejection fraction 35%, complete left bundle branch block and QRS between 120ms and 149ms, sinus rhythm, cardiac function classification (NYHA) grade , or NYHA that can be active after treatment Patients with grade IV heart failure;

Left ventricular ejection fraction 35%, non-left bundle branch block and QRS 150ms, sinus rhythm, heart function classification (NYHA) grade , or active drug treatment NYHA grade heart failure patients ;

Patients with heart failure with left ventricular ejection fraction 35% and AF with ideal drug treatment can guarantee 100% ventricular pacing after ventricular pacing or CRT indication and AV node ablation or medication;

After ideal drug treatment, the left ventricular ejection fraction is 35%, requires new equipment or replacement, and depends on ventricular pacing (40%).

Sudden Cardiac Death (SCD) risk (main SCD risks: history of cardiac arrest, spontaneous persistent VT, spontaneous non-sustained VT, family history of SCD, syncope, left ventricular thickness 30mm, abnormal blood pressure response during exercise; possible SCD Risks: Patients with obstructive hypertrophic cardiomyopathy who have atrial fibrillation, myocardial ischemia, obstruction of the left ventricular outflow tract, high risk of mutation, and strong physical activity should be implanted with DDD-ICD.

ICD's recommendations are as follows:

Non-ischemic dilated cardiomyopathy, significant left ventricular dysfunction, unexplained syncope;

persistent ventricular tachycardia, even if the ventricular function is normal or near normal;

Patients with hypertrophic cardiomyopathy have more than one major risk factor for SCD;

Arrhythmic right ventricular dysplasia / cardiomyopathy patients have a major risk factor for SCD (including electrophysiological examination-induced VT, non-persistent VT for ECG monitoring, male, severe right ventricular enlargement, and extensive right ventricular involvement, " 5 years old with involvement of the left ventricle, history of cardiac arrest, unexplained syncope);

Patients with long QT syndrome develop syncope and / or ventricular tachycardia when using beta blockers;

Patients waiting for heart transplant outside the hospital;

Brugada syndrome with syncope;

Brugada syndrome with ventricular tachycardia but no sudden cardiac arrest;

Catecholamine-sensitive patients with ventricular tachycardia, syncope and / or ventricular tachycardia after -blockers;

Patients with cardiac sarcoidosis, giant cell myocarditis, and trypanosomiasis in South America.

Of course, the guidelines do not cover all clinical situations. For a specific patient, the indications for permanent cardiac pacing are not always clear. In general, irreversible, symptomatic bradycardia is the main indication for implanting a permanent pacemaker. The decision of whether a permanent pacemaker should be implanted should be made by the physician in charge, taking into account the patient's specific condition, the patient's wishes, and the financial situation.

Implant-related complications

Most complications, such as careful operation during surgery, should be avoided, and some are difficult to completely avoid. Incidence is closely related to the experience of the implant physician.

1. Arrhythmias usually do not require special treatment.

2. Local bleeding is usually self-absorbed. When there is obvious hematoma formation, the blood can be squeezed out under pressure under strict aseptic conditions.

3. Subclavian vein puncture complications and management

Pneumothorax: A small amount of pneumothorax does not require intervention. Pneumothorax compresses the lung tissues. When 30% of the pneumothorax is compressed, a suction or drainage tube is required.

Into the subclavian artery by mistake: The needle and / or guide wire should be removed and locally pressurized to stop bleeding (never insert an expansion tube), usually without special treatment.

4. Heart perforations are rare. Handling: Carefully sprinkle the catheter back into the heart cavity, and closely observe the patient's blood pressure and heart condition. Once pericardial tamponade occurs, open the chest for pericardial drainage or cardiac repair. Avoid positioning on the perforation when continuing to place the electrode.

5. Infection is rare. Treatment: Once the patients with local abscess formation have little chance of healing through conservative treatment, they should be cut open and drained as early as possible, debride, and remove the electrode lead in the wound.

6. Diaphragm stimulation is rare. Can cause stubborn hiccups. Left ventricular electrode leads are more common. Treatment: Reduce the pacemaker output or change to bipolar pacing. If symptoms persist, reposition the electrodes.

Complications and treatment related to electrode lead

1. Threshold raising treatment: increase the energy output through program control, and need to replace the electrode position or lead wire if necessary.

2. The X-ray examination can be found when the electrode dislocation and micro dislocation are obviously displaced, and the X-ray fluoroscopy of the micro dislocation shows that the electrode head is still in place, but the contact with the endocardium is actually poor. Treatment: Reoperation is usually required to adjust the electrode position.

3. The electrode wire is broken or the insulation layer is broken. If the impedance is very low, the insulation layer is broken; if the impedance is very high, the electrode wire is broken. Treatment: Need to re-implant a new electrode lead.

Pacemaker-related complications and management

With the development of engineering, the failure of pacemakers such as pacemakers has become rare. Occasional pacemaker failure is pacemaker reset, the pacemaker battery is exhausted in advance, the former is due to external interference (such as strong Magnetic field), the pacemaker needs to be reprogrammed, and the latter needs to be replaced in time.

In addition, sensory dysfunction may still occur, and improper sensing parameters are often set for the pacemaker rather than the mechanical failure of the pacemaker itself, including poor perception and excessive perception.

Pacemaker-related complications and management

1. Pacemaker Syndrome (PMS) Some patients using a VVI pacemaker may experience signs of dizziness, fatigue, decreased mobility, hypotension, palpitations, and chest tightness. In severe cases, heart failure may occur. Pacemaker syndrome. Treatment: If PMS occurs and is not a pacing dependent person, slow down the pacing frequency to restore your heart rhythm as much as possible, and replace it with an atrioventricular sequential pacemaker if necessary.

2. Pacemaker-mediated tachycardia (PMT) is tachycardia caused by the active and continuous involvement of a dual-chamber pacemaker. For the atrial electrode to sense the back-propagating P wave, start the AVD and issue ventricular pulses at the end of the AVD. The latter excites the ventricle and then passes back to the ventricle, forming circular motor tachycardia. Preventricular contractions and poor atrial pacing are the most common causes of PMT. Prevention can be achieved through program control for longer PVARP, appropriate reduction of atrial sensory sensitivity, delayed sensory atrioventricular interval, or activation of pacemaker automatic prevention procedures for PMT. Termination methods include placing a magnet on the pacemaker, extending PVARP, program-controlled pacing methods for atrial nonsensing (DVI, VVI, DOO) or non-tracking mode (DDD), or enabling the automatic recognition and termination procedures of the PMT that the pacemaker has .

1. Severe heartbeat is slow. A pacemaker should be implanted in patients with a cardiac arrest of more than 3 seconds or a heart rate of less than 40 times, especially in patients with dark eyes and sudden fainting. This is also the most important and initial area of treatment for pacemakers.

2. Weak heart contraction. If the disease destroys the heart muscle or changes its original shape, it can cause the heart muscle to fail to contract vigorously. Decreased systolic function will cause insufficient pumping of the heart's blood, and various parts of the body will not be able to obtain sufficient fresh blood, causing various symptoms such as dizziness, chest tightness, and fatigue. For example, congestive heart failure and severe hypertrophic obstructive cardiomyopathy that are ineffective in drug treatment, multiple pacemakers can be installed in each part of the heart, and multiple electrical stimulation commands can be generated simultaneously to help myocardial contraction.

3. Cardiac arrest. The heart can be dead for a few minutes if it stops beating. Some diseases can cause cardiac arrest or fatal malignant ventricular arrhythmias (such as rapid ventricular tachycardia, ventricular fibrillation). A pacemaker with a defibrillator function can be installed. Restores the heart's regular beating.

4. In the comprehensive treatment of certain heart diseases (carotid sinus hypersensitivity syndrome, vasovagal syncope, idiopathic Q-T prolongation syndrome, prevention of rapid atrial arrhythmia, etc.), a pacemaker is still indispensable or The only cure.

Common failures of pacemaker implantation

Unlike other interventional cardiac interventions, successful pacemaker implantation is only the relatively simple first step performed by a doctor. The tedious but important task is the long-term follow-up of patients after surgery. Follow-up work began on the day of implantation and continued throughout the patient's life.

(1) Teach patients to self-test the pulse after surgery, because checking the pulse is a simple and effective way to monitor the pacemaker's work. When monitoring your pulse, make sure that you are in the same physical state every day, such as when you wake up every morning or after sitting 15mim.

In the early stages of pacemaker placement, the pacing threshold is often unstable and needs to be adjusted in time. Therefore, it is necessary to visit the hospital regularly, usually once every two weeks within one month and once a month within three months (depending on the patient). There are many factors that cause the threshold to increase. In addition to the electrode location, factors such as insufficient sleep, full meals, antiarrhythmic drugs, and hypertension may have an effect. Therefore, postoperative patients should maintain a good mood, ensure a regular life and work and rest system, and avoid all possible adverse factors. The follow-up period and content follow-up should be loose on both ends.

(B) common failures and treatment

It is usually manifested as no stimulus, incapable of being captured, or imperceptible.

1. No stimulation pulse may have one of the following common causes:

(1) If the problem can be solved after the magnet is placed, the cause is mostly over-perception or the use of some normal pacing functions such as hysteresis. The former is mostly caused by electromagnetic interference, myoelectric potential, cross-sensing, or T-wave oversensing, etc., so the sensing sensitivity should be reduced, while the latter need not be processed.

(2) Electrode lead or pacemaker failure: It may be due to loose or disconnected screws connected to the pacemaker, electrode lead conductor failure, or damage to the electrode lead insulation or battery exhaustion. Treatment: Re-tighten the screws or replace the pacing electrode lead or pacemaker.

2. Failure to seize may have one of the following reasons:

(1) The pacing threshold is increased: the output of the electrode at the end of the electrode lead cannot effectively stimulate the heart muscle connected to the electrode, which is for egress block. Treatment: It can temporarily increase the output voltage and correct the possible causes, such as applying hormones, correcting electrolyte disorders, or changing the pacing position.

(2) Electrode lead failure, electrode dislocation, or battery exhaustion: Take replacement or relocation of electrode lead or pacemaker according to specific reasons.

3. Failure to perceive may be for one of the following reasons:

(1) The endocardial signal is too small (temporary changes caused by electrolyte disturbances, acidosis, or permanent changes in local endocardium caused by myocardial infarction or cardiomyopathy): At this time, it is necessary to increase the sensitivity of the sensor or change the pacemaker position.

(2) Electrode dislocation, malfunction or pacemaker failure. Relocate or replace the electrode lead or pacemaker according to specific reasons.

Precautions after pacemaker implantation

Absolutely bed-ridden within 1.24 hours, take supine or low-slope position, do not turn over, the appropriate lateral position on the second day after surgery. During the first week after operation, the limbs were braked and the rhythm changes were observed. During the postoperative recovery period, you should follow the principle of gradual and progressive exercises to avoid violent repetitive hand shakes on the affected limb, large abduction, lift up and shoulder load on the affected side, and jump from high to low. If there is a shoulder muscle twitch, the lead may be detached, and you should go to the hospital immediately.

2. The local dressing should be kept clean and dry at an early stage. If the dressing gets wet or falls off, it should be replaced in time. After the stitches are removed, the local skin must be kept clean and not worn through tight underwear. If local redness, swelling, or even skin ulceration occurs after surgery, it should not be handled at home at this time. If accompanied by systemic symptoms such as fever, the possibility of infection should be considered, and the hospital should be examined and treated in time.

Nursing of pacemaker implantation during rehabilitation

1. Generally speaking, the symptoms of dizziness and fatigue will improve after the pacemaker is installed. However, if the above symptoms persist after surgery, especially for patients with ventricular pacing, you should go to the hospital to check whether artificial pacing has occurred. Organ syndrome. Once the diagnosis is obvious, you need to change the atrial synchronization or atrioventricular sequence pacemaker.

2. Whether the medication should be continued after the pacemaker is placed depends on the patient's condition. The pacemaker can only solve the problem of cardiac conduction. If the original heart function is poor or accompanied by other heart diseases, you should still take medication according to the condition. This can effectively maintain the heart function and reduce the pacemaker's effect on the heart function. influences.

3. Exercise of limb function early after operation is conducive to local blood circulation and incision healing. Patients should be persuaded to dispel their concerns, and an exercise program can usually be started after the stitches are removed. There may be mild incision pain at an early stage. This is normal and should be continued after discharge. Exercise should be done step by step, not to be rushed, and gradually increase the exercise of arm lifting, chest expansion or "climbing the wall" until the arm can be raised above the head to touch the contralateral earlobe, and restore normal limb function as soon as possible, which is to improve the quality of patients' postoperative life Guarantee.

4. In general, the pacemaker's work has stabilized after being discharged from the hospital, but many patients often worry that the pacemaker may suddenly fail or stop working, so the necessary explanation is the key to relieve their psychological stress. It should be explained to the patient that it is impossible to suddenly run out of power in the battery, it will only be consumed slowly. So the heart never stops suddenly. But sometimes there are some unexpected situations. When the patient accidentally enters the high-voltage electromagnetic field or accidentally exceeds the safe distance between the mobile phone and the pacemaker, the patient may have some strange body feelings. In severe cases it may cause arrhythmias. At this point the patient need not panic, as long as they leave the scene, the pacemaker will return to normal quickly. In some unexpected situations, when the pacemaker is severely impacted, or the limb is overloaded, the pacemaker may work abnormally, or even the lead is disconnected. At this time, patients may have varying degrees of discomfort. Patients with severe pacemaker dependence may reappear with symptoms of darkening and dizziness, and self-tested pulses will find that the heart rate slows below normal. At this time, you should stop activities immediately, brake the affected limb, bring a pacemaker card (the important information about the pacemaker implantation time, type, etc.), and rush to the hospital as soon as possible for medical examination.

Pacemaker implantation installation process

Pacemaker installation surgery is performed by a cardiologist and is usually performed under local anesthesia. The method is to insert an electrode lead from a vein under the arm or the clavicle, and insert it into a predetermined cardiac pacing position under X-ray fluoroscopy, fix and detect it. Then a pacemaker connected to the electrode lead is embedded in the chest, the skin is sutured, and the operation can be completed.

Pacemaker implantation safety

Many patients are concerned about the installation of pacemakers. In fact, it is safe to install pacemakers. "Pacemakers can be divided into single-chamber pacemakers and dual-chamber pacemakers (pacing left and right atrium, Or right atrium and right ventricle), three-chamber pacemaker (pacing right atrium and left and right ventricles). "He Meixian said that doctors will choose the appropriate pacemaker installation according to the specific circumstances of the patient.