Implantable Devices System page Archivi - AF-ABLATION

The Pacemaker is an electronic device capable of delivering electrical impulses to assist the heart beat in patients whose heart rate is excessively low. The pacemaker consists of a case (which contains the electronic circuits, which regulate the stimulation function, and the battery, generally lithium) and the leads.

Depending on the type of pacemaker, which is chosen based on the clinical condition, a single catheter (usually in the right ventricle, single chamber pacemaker) or two catheters (generally in the atrium and right ventricle, dual chamber pacemaker) can be implanted. In some cases, a third catheter can also be implanted, directed to the wall of the left ventricle through the coronary sinus (pacemaker-resynchronizer, or CRT-P).

When is it necessary to implant a Pacemaker?

Under normal conditions, the electrical impulse, which allows the heart to contract and perform its function, originates in a group of cells located in the right atrium and is propagated to the whole heart through a conduction system whose main element is the ventricular atrium node.

The implantation of a definitive pacemaker is necessary in the presence of symptoms due to a low heart rate. The heartbeat is too slow when there is an alteration in the origin (for example, due to the disease of the sinus node) or in the conduction of the electrical impulse (for example, an atrioventricular block); in these cases the main disturbances are dizziness, weakness, shortness of breath, syncope (or loss of consciousness).

How is the Pacemaker implanted?

The implantation of a pacemaker is performed under local anesthesia. The first phase is the introduction of the leads, which are electrical wires that transmit impulses to the heart, through the cephalic vein and / or the subclavian vein (generally on the left). The approach to these vessels occurs with different techniques in the shoulder region under the clavicle.

The catheters are pushed to the heart under the guidance of X-rays and are positioned in the heart chambers (right atrium and / or right ventricle) in optimal positions to ensure the stimulation function (or pacing function) and the function of capturing the spontaneous electrical activity of the heart (or sensing function).

After checking the stability and effectiveness of the stimulation, the catheters are connected to the pacemaker. By means of a small incision, the pacemaker is inserted under the skin, creating a special pocket, and the small wound is closed with some stitches, partially absorbable. The procedure lasts on average 45-90 minutes.

What are the risks of implanting a pacemaker?

The procedural risks are generally very low, and complications are very rare. Among the possible complications, the most common are the following:

• local hematoma, which generally resolves spontaneously in a few days;
• damage to the vessels through which the catheters are introduced (thrombophlebitis, deep vein thrombosis, etc.);
• damage to the lung (pneumothorax), which can occur during puncture of the subclavian vein and sometimes requires the application of a small drainage tube;
• pericardial effusion, which can be resolved spontaneously or in rare cases may require drainage.

In even rarer cases, as a result of pocket infections or endocarditis, pacemaker explantation may be required.

How are checks performed after pacemaker implants?

An outpatient evaluation of the surgical wound is performed about 7-10 days after the implant and, if non-absorbable suture thread is used, the stitches are removed.

Patients with pacemakers must subsequently undergo regular (generally every six months) checks of the device, according to the timing recommended by the Arrhythmologist Cardiologist.

The checks can be closer together in case of particular arrhythmias, problems related to leads, and in the period near the end of life of the device.

Checks of patients with pacemakers are generally carried out on an outpatient basis, and in some cases, depending on the specific pathology, remote telemetry control or remote monitoring of cardiac devices is also recommended (for example, in the case of pediatric patients, or in case of pacemaker resynchronizers, or in case of malfunction of the leads or of particular arrhythmias).

If you want to know more → Remote device monitoring

Does the pacemaker implantation limit normal daily activities?  

Patients undergoing a pacemaker implant usually return to normal daily activities in a very short time after the implant. In the first three months after the implant, it is generally recommended to avoid intense physical activity or carrying heavy loads. Thereafter, the patient can gradually return to their normal lifestyle, and resume the physical activity to which they were accustomed after completing the recovery period.

Driving the car can be resumed with some limitations, and in some cases the driving permit is issued for a shorter period than normally. The use of a seat belt in the car is not recommended for patients with pacemakers.

It is possible to practice physical and sport activity after pacemaker implantation? 

After the first three months, in general, the patient can return to non-competitive physical activity. In general, caution should be exercised in the first months after implantation in sports, such as tennis, golf, or swimming, that involve the upper limbs in particular, avoiding excessive traction that may cause dislocations of the leads.

Particular caution should be exercised in sports that involve violent physical contact (e.g. football, rugby, wrestling), or at risk of falling (e.g. downhill skiing) or bumps at the implantation site (boxing, judo), as these could damage the device or leads.

Competitive physical activity is not prohibited for pacemaker wearers, although the specific sports activity should be reviewed by the cardiologist.

It is possible to pass through the security gates after pacemaker implantation?

Before entering a security gate, in particular at the airport, the patient must inform the surveillance staff that they are carrying a cardiac device and show the identification certificate. Then the patient will cross the passage at a normal pace, taking care to move away from the system if he feels dizzy or an acceleration of the heartbeat.

Airport security systems are magnetic detectors and will therefore issue an alarm signal when they detect the metal casing of the cardiac device. If the surveillance staff uses a handheld metal detector to monitor passengers, tell the attendant not to place or pass the instrument over the cardiac device.

For further information on the compatibility of the devices with the electromagnetic security gates, consult the instructions provided by the individual manufacturing companies.

If you want to know more> Information from the Manufacturers

What medical and orthodontic procedures can be performed after pacemaker implantation?  

Before undergoing any medical procedure, always inform your doctor, dentist or technician about the presence of the pacemaker. Before performing the procedure, these professionals may need to contact the cardiologist, particularly if the procedure is new or unusual.

Some procedures may affect the function of the cardiac device, and therefore require precautionary measures to avoid or minimize any effects on the patient or on the device itself.

If you want to know more> Medical procedures in cardiac device carriers

Can magnetic resonance imaging be performed after pacemaker implantation?  

In general, magnetic resonance imaging (MRI) is still prohibited in all wearers of old generation cardiac devices (because of the risk that the magnetic fields generated may damage the components or inhibit the function).

The scientific guidelines and recommendations of the manufacturing companies do not contraindicate the examination in patients with new generation MRI-conditional devices (provided that the required safety parameters are respected: imaging protocols, monitoring of both device function and patient parameters during the examination).

If you want to know more> Magnetic Resonance Imaging in Cardiac Device Carrier

What happens in the event of a battery drain or a pacemaker malfunction?

In the event that during the checks (carried out in the clinic or remotely) the depletion of the device battery is detected, the replacement is scheduled, which is carried out after a short hospitalization. In general, the replacement takes place through the incision of the skin, with the removal of the old device and the repositioning of a new device in the same pocket, after the reconnection of the leads, which instead are not generally replaced.

If, however, a malfunction or breakage of a lead is detected, an overhaul of the implant may be necessary, with the replacement and repositioning of the leads. This review is performed after hospitalization, and the specific procedures necessary will be explained directly by the doctors on a case-by-case basis.

WHAT IS THE IMPLANTABLE CARDIAC DEFIBRILLATOR?

The implantable cardiac defibrillator (ICD) is a device used to recognize and treat ventricular arrhythmias, specifically ventricular tachycardia and ventricular fibrillation, which would be potentially fatal if not interrupted promptly. The anti-tachycardia function of the ICD consists of delivering pulses or shocks to stop ventricular arrhythmias, and thus preventing syncopal episodes and sudden cardiac death. In addition to the anti-tachycardia function, the ICD is equipped with anti-bradycardia functions, so they are able to stimulate the heart if the heart rate becomes too low (similar to the pacemaker).

The first ICD was developed in the 70’s, mainly by Marcel Mirowski, of Baltimore. The first implants were performed in the abdominal area, and the electrodes for defibrillation were applied to the surface of the heart (epicardium). Currently, the ICD is surgically implanted subcutaneously in the pectoral region, preferably on the left, positioning the electrodes intravenously in the right ventricle, and possibly also in the right atrium (in bicameral ICDs), and in the veins at the left ventricle surface (in the case of ICD resynchronizers, ICD-CRT). Currently, in addition to the classic intravenous ICDs, there are also subcutaneous ICDs, which have specific clinical indications.

FOR WHICH PATIENTS IS THE ICD RECOMMENDED?

Patients who are candidates for an ICD implant can be divided into two categories:

1. SECONDARY prevention patients, i.e. patients who have already had ventricular cardiac arrhythmias:

• patients who survived a first cardiac arrest due to ventricular fibrillation 

• patients with very rapid sustained ventricular tachycardias that cause loss of consciousness, not controlled by medical therapy and / or other electrical therapies, such as catheter ablation.

1. Patients in PRIMARY prevention, i.e. patients who have not already had malignant ventricular arrhythmias, but are considered at high risk of developing such arrhythmias:

• patients with ischemic heart disease, with low ejection fraction (FE <35%) and presence of heart failure

•  patients presenting with rare clinical conditions, which according to precise individual risk stratification criteria are considered to be at high risk of sudden cardiac death according to current guidelines, such as long QT syndrome, Brugada syndrome, arrhythmogenic dysplasia of the right ventricle, hypertrophic cardiomyopathy, dilated cardiomyopathy, non-compact myocardium

HOW DOES THE IMPLANTATION OF AN INTRAVENOUS ICD BEGIN?  

Similarly to pacemaker implantation, ICD implantation is almost always performed under local anesthesia and lasts about 60 minutes on average. The procedure is generally well tolerated; in case of pain the dosage of local anesthetic is increased or, in rare cases, for example in pediatric patients, deep sedation is performed with anesthetic assistance.

The first phase consists of the positioning of the leads, that is the “electric wires” that stimulate the heart; their number can vary from one to three depending on the type of device that needs to be implanted. The leads are inserted through the cephalic vein and / or the subclavian vein (usually left, depending on the anatomy of the individual patient) and are pushed to the heart under the fluoroscopic guide (x-rays).

The main catheter (defibrillation catheter) is placed at the tip of the right ventricle (single-chamber ICD, or ICD-VR). In some cases, a second catheter is also implanted in the right atrium (ICD Bicameral, ICD-DR). In cases where cardiac resynchronization is required, a third cataract can be implanted through the coronary sinus in the cardiac veins to stimulate the left ventricle wall (ICD-CRT or CRT-D). The electrodes are positioned, with the help of dedicated software programs, at the points where they sense the cardiac activity and where they are able to stimulate the heart using the lowest possible energy.

After checking the stability and effectiveness of the stimulation, the catheter (or catheters) are fixed and connected to the stimulator case. By a small incision, the defibrillator is inserted into the pectoral region subcutaneously or under the pectoral muscle.

At this point, it is necessary to test the correct functioning of the system. During this test, the cardiologist causes the onset of a rapid ventricular arrhythmia and causes the defibrillator to recognize and treat it appropriately and effectively. In this phase, a deep sedation is used to avoid the patient from feeling unpleasant sensations related to the onset of the arrhythmia and the consequent electric therapy.

The incision is subsequently closed with suture thread (often resorbable, so without the need for subsequent removal of the stitches). A chest X-ray is also performed in order to evaluate the positioning of the leads. After the implant, after a brief period of lodging, the electronic control of the device is performed, and then the patient is discharged the day after the implant.

WHAT ARE THE COMPLICATIONS RELATED TO THE ICD IMPLANT?

Complications related to ICD implantation are rare and generally not serious. The most frequent is the formation of a local hematoma during implantation (which is generally reabsorbed spontaneously within a few days).

In very rare cases, it is possible that damage is caused to the venous vessels used for access (with consequent thrombosis and possible phlebitis), an eventual pneumothorax in the case of puncture of the subclavian vein (passage of air inside the pleural cavity, in most cases asymptomatic and self-solvent, rarely requiring temporary drainage positioning), a possible pericardial effusion secondary to perforation of the myocardial wall of the electrocatheters (very rare occurrence, which in some cases may require temporary drainage positioning).

A possible complication, which generally occurs in complex cases with multiple pathologies and multiple device replacements, is the infection of the device pocket or the endocarditis starting from the leads. These infections are very difficult to treat and may require the removal of the entire ICD.

HOW DO THE CHECKS GO AFTER THE ICD IMPLANTATION?

About 7-10 days after the implantation, an out-patient surgical wound assessment is performed and, in the case of non-absorbable suture thread, the stitches are removed.

Patients with implantable defibrillators must subsequently undergo a regular (generally every six months) check of the device, according to the recommended timing based on the specific pathology.

It is currently recommended by the current guidelines that ICDs be checked regularly through remote telemetry control or remote monitoring of cardiac devices.

If you want to know more > Remote monitoring of devices

WHAT HAPPENS WHEN AN ICD DETECTS AN ARRHYTHMIA?

The ICD is programmed to recognize certain ventricular cardiac arrhythmias and intervene when necessary to stop the arrhythmia and restore the normal rhythm. The intervention of the ICD can take place in the following ways:

1. Anti-tachycardia pacing (ATP): in the event that the arrhythmia is fast and regular (ventricular tachycardia) the ICD attempts to deliver rapid pulse trains to stop the arrhythmia. Such therapies are generally felt by the patient, or are felt as mild palpitations
2. Cardioversion (CV): in the case of ventricular tachycardias that are not interrupted by the ATP, the ICD can deliver a low or medium energy shock (usually 4-10 Joules), which is generally not felt or felt like a thud in the chest
3. Defibrillation (DC): in the event that the arrhythmia is very fast and chaotic, typically in ventricular fibrillation (VF), the ICD delivers a high-energy discharge (generally 30-40 Joules), which is felt, if the patient is still conscious, like a big blow or a kick in the chest. If the VF is not interrupted at the first shock, the ICD can deliver up to 6 consecutive shocks.

Anti-bradycardia pacing: if the heart rate is too slow, the ICD can deliver a stimulation to the atrium or ventricle, behaving like a pacemaker.

WHAT YOU NEED TO DO AFTER A SHOCK

This check can be performed in the hospital or directly from home through Remote Monitoring. This check also serves to verify whether it is necessary to carry out further diagnostic tests (for example coronary angiography) or to modify the drug therapy or to schedule the ablation of the arrhythmia.      

In the event that the ICD mistakenly interprets the presence of a ventricular arrhythmia (which can occur in the case of high-frequency rhythms, due to sinus tachycardia or supraventricular arrhythmias including atrial fibrillation, or due to the recognition of anomalous signals due to rupture of an electrocatheter or an electrical interference) an inappropriate shock can occur. In this case, it is always necessary to investigate the device, either directly in the hospital or remotely.

DOES THE ICD IMPLANT LIMIT NORMAL DAILY ACTIVITIES? 

Patients undergoing an ICD implant usually return to normal daily activities within a very short time after the procedure. Within the first three months after implantation, it is generally advised to avoid intense physical activity, including carrying heavy loads. Later, the patient can gradually return to his or her normal lifestyle and resume the physical activity he or she was used to after completing his or her recovery period.

Sexual activity can also be resumed normally after ICD implantation. Sexual activity leads to an increase in heart rate, which in very rare cases can lead to an erroneous recognition of the arrhythmia by the device, which can lead, in extreme cases, to the delivery of inappropriate therapies (including inappropriate shocks). If this happens, the ICD must be reprogrammed, and in any case the shock is not a danger to the partner.

Car driving can be resumed with some limitations (see ICD and driving license). The use of seat belts in cars is not recommended for patients with ICDs (such as in patients with pacemakers).

IT IS POSSIBLE TO ENGAGE IN PHYSICAL AND SPORTS ACTIVITY AFTER ICD IMPLANTATION?

After the first three months, in general, the patient can return to non-competitive physical activity. In general, caution should be exercised in sports, such as tennis, golf, or swimming in the first few months after implantation, particularly involving the upper limbs, avoiding excessive extension that can cause dislocations of the leads.

In general, physical activity leads to an increase in heart rate, which in rare cases can lead to an erroneous recognition of the arrhythmia by the device, which can lead in extreme cases to the delivery of inappropriate therapies (including inappropriate shocks). To avoid this risk, personalized relatively delayed recognition is planned for young and athletic people.

Then there are some sports that have a high “intrinsic risk”, in which the loss of control due to an arrhythmia and shock, even for a few seconds, can have potentially serious effects, such as motoring, mountaineering, underwater sports, parachuting, etc.

Particular caution must be exercised in sports that involve violent physical contact (for example, football, rugby, wrestling), or a risk of falling (for example, downhill skiing) or collisions at the site of implantation (boxing, judo) as this could damage the device or the leads.

IT IS POSSIBLE TO TRAVEL AFTER ICD IMPLANTATION?

Most patients undergoing cardiac device implantation can travel without limitations, unless there are contraindications related to the underlying clinical condition.

Before leaving, it is advisable to consult your doctor in reference to:

• Specific health or behavioral recommendations
• How to behave in the event of discomfort or appearance of symptoms
• How to find a cardiology institute, emergency service, or medical assistance in your destination

IT IS POSSIBLE TO GO THROUGH SECURITY SCREENINGS (AIRPORTS, BANKS, ETC) AFTER ICD IMPLANTATION?

Before crossing a security checkpoint, especially at the airport, the patient must inform the security staff that he / she has a cardiac device and present the identification certificate. Then the patient will go through the security machine at a normal pace, taking care to leave the machine if he or she feels dizzy or has an accelerated heartbeat.

The airport security systems are magnetic detectors, and therefore they will launch an alarm signal when they detect the metal casing of the cardiac device. If the surveillance staff uses a hand-held metal detector to check the passenger, ask the operator not to place or pass the instrument over the cardiac device.

ARE ELECTROMAGNETIC FIELDS DANGEROUS FOR ICD PATIENTS?

Some electrically powered appliances with magnets can create energy fields, which can alter the normal operation of the ICD. 

The greater the proximity of the object, and the greater the energy of the device, the greater will be the electromagnetic field that can be formed. In most cases, electromagnetic energy fields are limited and weak and do not affect the functioning of the cardiac device, but electrical equipment with a stronger energy field, such as welding machines, chainsaws, mowers, and other industrial machinery, can produce interference and alter the normal functioning of the ICD.

Devices that emit low-energy electromagnetic waves (such as microwave ovens, mobile phones, or computers) can be used safely, but it is useful to maintain a certain distance between these devices and the ICD (at least 30 cm), so, for example, it’s better to avoid putting your smartphone in your jacket pocket or getting too close to the microwave oven.

WHICH MEDICAL AND ORTHODONTIC PROCEDURES MUST BE AVOIDED AFTER ICD IMPLANTATION?

Before undergoing any medical procedure, always inform the doctor, dentist or technician of the presence of the ICD. Before performing the procedure, these professionals may need to contact the cardiologist, particularly if the procedure is new or unusual.

Some procedures may affect the functioning of the cardiac device and therefore require precautionary measures to avoid or minimize any effects on the patient or on the device itself.

PROHIBITED MEDICAL PROCEDURES

Individuals with ICDs should not be subjected to the following medical procedures, unless the ICD is properly programmed or temporarily deactivated:

• Trans-catheter radiofrequency ablation
• Diathermic treatment (with shortwave high frequency, or microwave)
• MRI exams (magnetic resonance imaging) or MRA (angiography with magnetic resonance)

MEDICAL PROCEDURES TO BE CARRIED OUT WITH PRECAUTION

Some medical procedures can be performed safely with the adoption of specific precautions by the doctor to avoid potential problems with device operation or interference:

• Computerized axial tomography (TC o TAC)
• Diagnostic ultrasound
• Electrocautery
• Electrolysis
• External defibrillation and elective cardioversion
• High energy radiotherapy
• Hyperbaric oxygen therapy (HBOT)
• Lithotripsy
• Ultrasound therapy
• Transcutaneous electrical nerve stimulation (TENS)
• Transmission circuits for hearing aids

ALLOWED MEDICAL PROCEDURES

There are many medical procedures that do not affect the functioning of the ICD:

• orthodontic procedures involving the use of drills or ultrasound probes for oral hygiene and oral cavity radiographs.
• diagnostic radiographs, for example for chest X-rays and mammograms.

However, the tools used for these procedures must be used correctly and properly stored. However, it is advisable to consult your doctor to assess the potential risks and benefits of the medical procedure.

WHAT ARE THE LIMITATIONS ON DRIVING AFTER ICD IMPLANTATION?

The current European guidelines prohibit commercial vehicle driving (in practice for driving licenses C, D, E). Conversely, regarding driving private cars (driving license B), the guidelines prohibit driving for 6 months after implantation of an ICD and, if there were no interventions or syncopal arrhythmias during the 6 months, the patient can drive. In case of ICD intervention, the observation period continues for a further 6 months. This interval is considered sufficient to assess the frequency and characteristics of the events. Abstention from driving becomes permanent in the case of frequent interventions of the ICD.

The presence of an ICD testifies in and of itself that a risk of transient loss of consciousness exists. It follows that each Commission has a certain discretion in giving or not giving the permission for driving to each patient on an individual basis, based on the specific individual risk of loss of consciousness, given that there could be a liability for the Commission itself in the event of an accident caused by a loss of consciousness in ICD carriers.

Reference: 

• Jung W, Anderson M, Camm AJ, et al. Recommendations for driving of patients with implantable cardioverter defibrillators. Study Group on ‘ICD and Driving’ of the Working Groups on Cardiac Pacing and Arrhythmias of the European Society of Cardiology. Eur Heart J 1997;18(8):1210-1219.

• Roberto Mantovan, Antonio Raviele, Pietro Delise, Paolo Stritoni.  Patente di guida e defibrillatore impiantabile: dalla parte del cardiologo, del giurista… o del paziente? G Ital Aritmol Cardiostim 2002;2:85-88

WHAT HAPPENS IN CASE OF EXHAUSTMENT OR MALFUNCTION OF THE ICD?

In the event that during the checks (carried out in the clinic or remotely) the exhaustion of the battery of the device is ascertained, replacement is scheduled, which is carried out after a brief hospitalization (sometimes in day hospital). In general, the replacement takes place through the incision of the skin, with the removal of the old device and the repositioning of a new device in the same pocket, after reconnecting the leads, which are not generally replaced.

On the other hand, if a malfunction or failure of a lead is detected, a check of the implant may be necessary, with the replacement and repositioning of the leads. This check is carried out after hospitalization, and the specific procedures required will be explained directly by the doctors on a case-by-case basis.

Refractory heart failure is a condition in which the maximum possible drug therapy fails to give satisfactory results to improve the circulatory conditions in patients with severe dilation and functional impairment of the left ventricle.

In some of these patients there is an electro-radiographic alteration called “left bundle branch block” (LBBB).

LBBB has been shown to cause alterations in cardiac mechanical activity and is therefore capable of worsening the contractile ability of the heart.

Today it is possible to correct at least in part these alterations, electrically stimulating the left ventricle with leads, positioned venously through the veins that run on the surface of the heart; these veins open into the right atrium and are therefore reachable in a similar way to the more classic sites of stimulation of the heart, i.e. the atrium and the right ventricle.

The combined stimulation technique of the right and left ventricle is called “biventricular pacing” and can give significant benefits to patients with heart failure.

It is good to specify however that this technique gives significant results only in the presence of the left bundle branch block; otherwise, there is no indication for this therapy.

In particular, biventricular pacing has proven capable of:
• improving the contractile efficiency of the left ventricle;

• increasing cardiac output;
• reducing, sometimes very markedly, the typical symptoms of heart failure, such as difficulty breathing (wheezing) and fluid retention.

What are leadless pacemakers?

With the evolution of technology, “wireless” leadless pacemakers have been developed, in which the pulse generator and the electrodes are contained in a single intracardiac unit, thus eliminating the presence of the conventional leads and subcutaneous prepectoral pocket.

So far, two types of leadless pacemakers have been developed for implantation in humans: Nanostim (from St. Jude Medical) and Micra (from Medtronic). The two devices differ in size: the Micra is shorter but with a slightly larger diameter (25.9 x 6.7 mm) than the Nanostim (42 x 5.99 mm) (figure 1). The devices also differ in the fixing system to the wall of the right ventricle: the Micra has a fixing system to the heart muscle consisting of 4 self-expanding wires, while the Nanostim has an active fixing system consisting of a screw that must be inserted in the thickness of the heart muscle. The longevity of the battery is similar to that of traditional pacemakers (7-10 years). The Nanostim device has been temporarily withdrawn from the market due to problems related to the coupling system, therefore only the Micra device is currently available.   

What are the advantages of leadless pacemakers?

The traditional pacemaker implantation presents critical issues, both in the operating phase and in the subsequent follow-up, given that there is a need for a surgical approach with incision of the skin and consequent scar development. In the acute phase, complications such as pneumothorax, cardiac perforation, dislocation of catheters, and hematoma of the pocket are possible, albeit infrequently. Local follow-up complications related to the presence of the subcutaneous generator and leads can occur, such as local or systemic infections with the potential for bacterial endocarditis, venous occlusion or tricuspid valve failure. This generally implies the need for explantation and complete extraction of the stimulation system, a procedure not without complications.

The advantages of leadless pacemakers are essentially related to their small size, minimum weight, the absence of connection mechanisms between the generator and electrodes (since they coexist in a single unit), the minimally invasive transcatheter implant procedure, and the much lower risk of infections.

Among the advantages, there is also the positive psychological impact linked to the absence of scar (since there is no need for surgical incision) and subcutaneous pocket. For the Micra device, the only leadless pacemaker currently in use, compatibility with total body MRI is also possible.

What are the limitations of leadless pacemakers?

Wireless cardiac pacing, however, still has some limitations related to the fact that, so far, only devices suitable for single-chamber stimulation are available (for now only right ventricular). Therefore, these systems are not suitable for patients who need dual chamber stimulation or resynchronization.

Furthermore, further long-term data are still needed to define the performance of the fixing mechanisms and the feasibility of extracting the devices.

What are the current indications of leadless pacemakers?

The current indications for leadless pacemakers therefore concern, at the moment, only a relatively small category of patients with the need for single chamber stimulation, such as patients with permanent ventricular slow atrial fibrillation, or in some cases, of paroxysmal atrioventricular block, or patients with a history of secondary infections of intracardiac devices.

How is the leadless pacemaker implantation performed?

The leadless pacemakers are positioned in the right ventricular cavity with a minimally invasive procedure via the catheter with a transcutaneous approach using the femoral vein, through a special introducer. The system therefore does not require the creation of a pocket and leaves no visible external scars.

What is the “Implantable Loop Recorder” (ILR)

The implantable loop recorder (ILR), also known as an injectable cardiac monitor (ICM) is a subcutaneous device used to diagnose heart rhythm disorders. These devices, available since the 1990s, have been improved and miniaturized over the past few years, and have become essential tools for the diagnosis of infrequent heart arrhythmias. The recent advent of injectable ILRs makes the procedure even simpler and more tolerated by patients. The loop recorder records and stores the ECG traces and can be interrogated remotely, i.e. without patient access to the facility.

What is the “Implantable Loop Recorder” (ILR) for?

The Implantable Loop recorder (ILR) is mainly used to document infrequent arrhythmic events in various clinical conditions, particularly in unexplained syncopes and palpitations. The latest generation ILRs are equipped with sophisticated algorithms capable of detecting episodes of atrial fibrillation. This new opportunity may provide physicians with systematic heart rhythm screening with possible effects on the management of patients’ anti-arrhythmic and anticoagulant therapy, after transcatheter ablation or after cryptogenic stroke.

In patients with unexplained recurrent syncope (with uncertain diagnosis) the ILR has proven to be the instrument with the highest diagnostic efficacy, since it reveals the relationship between events and cardiac arrhythmias, in particular the presence of slowing of the heart rhythm, or bradyarrhythmias, or pathological acceleration of the heart rhythm (supraventricular or ventricular tachyarrhythmias).

Example of bradyarrhythmia with symptomatic pause> 6 sec for presyncope in patient with ILR

• In patients with arrhythmic heart disease of unexplained origin, the ILR can identify episodes of tachyarrhythmia, due to paroxysmal supraventricular tachycardias, atrial fibrillation or more rarely, ventricular tachycardias.
• In patients following atrial fibrillation or flutter catheter ablation procedures, the ILR is used to evaluate the burden of atrial fibrillation, to evaluate the indication to continue anticoagulation therapy and antiarrhythmic therapy, or any need of a new ablation or electrical cardioversion intervention.

In patients with cryptogenic stroke (of uncertain origin) the ILR is used to look for episodes of silent paroxysmal atrial fibrillation, and to evaluate the indication for anticoagulant therapy, antiarrhythmic therapy, or transcatheter ablation for atrial fibrillation.

How does the Implantable Loop Recorder (ILR) work?

The Implantable Loop Recorder (ILR) is based on the recording of electrocardiographic traces by means of a dipole obtained through two electrodes inserted directly into the device case. ILR recorders are equipped with a retrospective memory (loop recorder memory), through which they record the ECG tracing continuously and store only a few recording segments afterwards. The storage takes place both in case of symptoms, when the patient manually activates the recorder by means of a special remote control, and automatically, if the device detects the presence of predefined arrhythmias. The duration of the recorded ECG traces varies according to the devices, up to a maximum of 30 minutes for the symptomatic episodes in the latest generation devices.

The internal storage capacity of the ECG traces is also variable depending on the devices: once this capacity is exhausted, in order to store new traces, the older traces are gradually deleted, and only a short text file remains available. This is the reason why ILRs are generally followed with remote monitoring.

ILR models produced by three different companies are currently available (Biotronic, Medtronic, Saint Jude Medical): with technological evolution, the size and weight of ILRs have gradually decreased, becoming similar or smaller than a package of chewing-gum, while the storage and duration of ECG monitoring have progressively increased, given that current systems are able to monitor the heart rhythm for up to 3 years.

How is the implantation (insertion) of the Implantable Loop Recorder (ILR) performed?

The Implantable Loop Recorder is either inserted into the subcutaneous tissue by creating a small surgical pocket, or, in the more recent models, the recorder is inserted through a special subcutaneous insertion system (injector) that creates a minimal skin breach without the need for surgical preparation of a pocket. Normally the implant takes place under local anesthesia, after a short hospitalization, in the precordial region, and there are no particular limitations in the days following the implant.

What are the complications of the Implantable Loop recorder system?

The complications of the implant are very rare, and are generally limited to mild pain or a small hematoma in the implant area, which regresses after a few days with mild pain-relieving drugs. In very rare cases where an infection or an important hematoma of the pocket occurs, the device may be explanted, which takes place through a small surgical incision, always under local anesthesia, without further general consequences.

How is the Implantable Loop Recorder information accessed?

The information access of ILRs can take place in the clinic through the classic programmers that are used to check implantable cardiac devices (pacemakers and defibrillators).

The information access for ILRs, as for other implantable cardiac devices, can however take place with remote monitoring, through a special transmission monitor that is delivered to the patient. In the case of ILRs, remote monitoring has a particularly important and indispensable function, since the remote information gathering from ILRs not only avoids unnecessary patient access to the hospital structure, as well as earlier diagnosis of any arrhythmic events, but it also prevents the saturation of the memory of the devices, significantly increasing the diagnostic efficacy.

What is our experience with ILR?

In our center, we have a long period of experience with ILR implants, which are used for the diagnosis of syncopal or presyncopal episodes of unexplained origin, the diagnosis of episodes of arrhythmic heart rate, and the monitoring of arrhythmic burden after transcatheter ablation of atrial fibrillation or tachycardias with or without accessory pathways, and finally to check for embolisms in atrial fibrillations in patients with cryptogenic stroke.

To date, over 2000 ILRs of the three manufacturing companies have been implanted in our center, and all devices are regularly monitored with remote monitoring. 

Each cardiac device (pacemaker (PM), defibrillator (ICD), resynchronizer (CRT)) has internal functions that protect it from the interference produced by most of the electrical equipment that is normally used in our homes. However, strong magnetic or electric fields may interfere with the normal operation of the device.

These electromagnetic interferences are, however, temporary, and normally do not damage the device, so they stop interfering once you move away from the emission source.

A list of possible equipment that we normally come into contact with in daily practices is provided. For particular equipment or machinery, it is necessary to ask the center that performs the implantation for information. 

Electronic equipment that can be used safely. 

• Electric can openers
• Hairdryer
• Vacuum cleaners
• Paging
• Patient alarm devices
• Fax and copier
• Electric and microwave ovens
• Blenders
• Washing machines and dryers
• Tanning beds
• CD / DVD players
• Personal Computer
• Radio and video recorders
• Electric heaters
• Electric toothbrushes
• Electric or gas stoves
• Remote Controls
• Warmer
• TV or radio speakers
• TV
• Whirlpool tubs
• Video games

Tools that can be used as long as they are not placed over the device (distance of 15-30 cm) 

• Manual massagers
• Electric razors
• Cordless telephones (home)
• Cell phones

Tools that can be used but must be kept about 30-60 cm from the device

• Stereo speakers
• Aspirators of foliage
• Chain saws
• Slot machines
• Suction snow plow
• Workshop tools (drills, table saws…)
• Lawnmower
• Remote controls with antennas

Tools that can be used with particular caution and kept more than 60 cm from the device 

• CB and police radio antennas
• Arc welders
• Engines and alternators that are turned on, especially those found in vehicles (avoid leaning over the hood of a turned on car because current generators create magnetic fields that could interfere with the correct operation of the device)

• Being in the driver’s or passenger’s seat is absolutely safe! 

Other possible electromagnetic interference 

• Burglar and shoplifting systems in shops 

You can easily cross at a normal pace, avoiding to stop near or lean on the columns.

• Bank and airport security systems

The metal parts of the devices could cause the alarm system of the metal detectors to sound, but the passage under the arches does not damage the device. Advise security personnel that you carry a cardiac device and, if searched with a manual metal detector, ask them not to linger long with the instrument on the device.

• Cell phones

Mobile phones can be used safely as long as they are kept at a distance of 15 cm from the pacemaker, for example by placing the mobile phone on the ear opposite the side of the implant. Do not carry the mobile phone in a breast pocket near the implant site. 

Medical and dental procedures that do not damage the device. 

• Dental drills and dental cleaning equipment
• Radiography
• TAC
• Ultrasound
• ECG machines
• Mammography (be careful not to damage the device by crushing it)

Before each surgery, inform the dentist or doctor of the presence of the cardiac device, contacting the implant center if in doubt. 

Medical and therapeutic procedures allowed only under particular conditions or not recommended 

Some medical and therapeutic procedures may affect the proper functioning of the pacemaker. Inform doctors and therapists of the presence of the pacemaker to take the necessary precautions. 

• Magnetic resonance

In general, MRI should be avoided, because the exam uses a strong magnetic field. Only some devices called MRI-conditional, under certain conditions can be subjected to this examination.

Also avoid entering the rooms where this examination is performed. This is the signal that distinguishes them:

• Diathermy 

This procedure uses an electric field to bring heat to the body’s tissues and should be avoided. 

• Electrocautery 

This technique is used in the operating room during surgical procedures to stop bleeding. It could create problems, particularly in pacemaker patients or ICD carriers. If necessary, specific programming or inactivation of the device is required.

• External defibrillation 

This is a procedure that is used in emergency medical situations. It can be carried out, but it is important to contact the implant center afterwards and check the correct operation of the device as soon as possible.

• Lithotripsy 

This is a procedure used to crush urinary tract stones (kidney stones) that can be carried out by taking certain precautions not to damage the device, which must be checked again after treatment.

• Radiotherapy for the treatment of tumors

This can be carried out, but not near the area where the pacemaker is implanted. Therefore, it must be carried out with careful precautions, and the device must be checked after treatment.

• TENS- unit of electrical stimulation of the nerves transcutaneously

This is a device that uses electric currents to control chronic pain, and must be avoided.

Obviously this list is not exhaustive, so it is necessary to contact the implantation center if there are doubts about the use of a specific device, tool, medical procedure or equipment.