7/6/23, 10:48 AM Cardiac implantable electronic devices: Long-term complications - UpToDate Official reprint from UpToDate www.uptodate.com 2023 UpToDate, Inc. and/or its affiliates. All Rights Reserved. Cardiac implantable electronic devices: Long-term complications : Jonathan Piccini, MD, MHS, FACC, FAHA, FHRS : N A Mark Estes, III, MD : Nisha Parikh, MD, MPH All topics are updated as new evidence becomes available and our peer review process is complete. Literature review current through: Jun 2023. This topic last updated: Feb 22, 2021. INTRODUCTION As more people are living longer with more medical comorbidities including significant cardiac disease, the number of permanent pacemakers (PPMs) and implantable cardioverter- st defibrillators (ICDs) inserted continues to increase. Beginning early in the 21 century, there has also been an expansion in the indications for cardiac implantable electronic devices (CIED, a term which includes PPMs and ICDs), resulting in device therapy becoming more complex and more prolonged over the patient's lifetime. As such, therapy with a CIED frequently involves multiple leads and multiple pulse generators per patient over each patient's lifetime with the device, exposing the patient to greater operative risk as well as ongoing risk related to the CIED. There are a variety of potential complications associated with CIED use, both at and around the time of implantation as well as long-term over the life of the patient and his/her device [1-3]. Efforts to avoid some of these complications have led to the development of new technologies (ie, leadless pacemakers, subcutaneous ICDs). The long-term complications associated with a CIED will be reviewed here. Procedural and peri-procedural complications associated with CIED implantation, as well as basic principles associated with PPMs, ICDs, and alternative technologies, are discussed separately. (See "Cardiac implantable electronic devices: Periprocedural complications" and "Permanent cardiac pacing: Overview of devices and indications" and "Implantable cardioverter-defibrillators: Overview of indications, components, and functions" and "Permanent cardiac pacing: Overview of devices and indications", section on 'Leadless systems' and "Subcutaneous implantable cardioverter defibrillators".) https://www.uptodate.com/contents/cardiac-implantable-electronic-devices-long-term-complications/print 1/22 7/6/23, 10:48 AM Cardiac implantable electronic devices: Long-term complications - UpToDate INCIDENCE Major complications requiring reoperation or hospitalization were analyzed in a cohort of 114,484 patients aged 65 years or greater (mean age 74.8 years, 72 percent male) who were enrolled in the National Cardiovascular Data Registry (NCDR) ICD registry and received a first ICD between 2006 and 2010 [4]. Over a median follow-up of 2.7 years, ICD-related complications requiring hospitalization or reoperation occurred at a rate of 6.1 per 100 patient-years. Patients who experienced a complication within the first 90 days following ICD implantation were at greater risk of all-cause mortality at one (hazard ratio [HR] 1.13, 95% CI 1.05-1.20) and three (HR 1.09, 95% CI 1.05-1.13) years [5]. A higher reoperation rate was seen in a Canadian study of 3410 first-time ICD recipients (implanted between 2003 and 2012, median follow-up 34 months), in which 12 percent of patients per year required reoperation [6]. Pulse generator malfunctions are a rare but significant long-term complication, particularly for patients who are pacemaker-dependent. In a 2006 meta-analysis which included patients from three registries, including 475,618 PPMs and 20,633 ICDs implanted between 1974 and 2004, rates of device malfunction (pulse generator only, no data on lead malfunctions were reported) were 1.3 per 1000 person-years for PPMs and 26.5 per 1000 person-years for ICDs, although the complication rates fell significantly over time [7]. Lead malfunctions, another rare but significant potential long-term complication, are more common in ICD leads, with significant variability in the rates of malfunction in certain leads. Reported lead failure rates have varied from 1 to 9 percent at two years, 2 to 15 percent at five years and 5 to 40 percent at 8 to 10 years [8-10]. Comparison of rates are confounded by varying definitions of lead failure, differences among lead models, varying patient and clinician characteristics, and limitations of methods for detection of lead malfunction [9]. MRI COMPATIBILITY Contemporary CIED and lead systems are generally labeled magnetic resonance imaging (MRI) compatible or MRI conditional, though management and behavior are variable among manufacturers/models and require some evaluation prior to scanning. Systems with older leads, abandoned leads, and some unusual features may not be strictly labeled MRI compatible. Several observational studies have shown that most patients can be safely scanned if appropriate precautions are taken [11,12]. Evaluation of patients with CIEDs for possible MRI imaging is discussed separately. (See "Patient evaluation for metallic or electrical implants, https://www.uptodate.com/contents/cardiac-implantable-electronic-devices-long-term-complications/print 2/22 7/6/23, 10:48 AM Cardiac implantable electronic devices: Long-term complications - UpToDate devices, or foreign bodies before magnetic resonance imaging", section on 'Cardiovascular implantable electronic device'.) LEAD COMPLICATIONS Lead-related problems include infection, lead failure (resulting in failure to pace, failure to shock, or inappropriate shocks), tricuspid valve regurgitation and/or damage, implant vein occlusion, and increased defibrillation thresholds (DFT). Abandoned leads also represent another type of lead-related complication insofar that they represent a contraindication to magnetic resonance imaging (MRI) scanning, which can be an impediment to medical care in some instances. Rarely, abandoned leads can affect device function by causing electrical artifacts. Venous thrombosis causes upper extremity swelling and discomfort in 5 to 10 percent of patients with chronic leads and may interfere with placement of additional leads [13]. Infection Infection of the generator pocket or leads can occur at the time of CIED implantation or at any subsequent time. Because infection of a CIED can be a life-threatening problem, complete hardware removal, including the CIED pulse generator and all leads, along with antibiotic therapy, are strongly recommended unless there is a reason to pursue palliative antibiotic therapy (eg, very short life-expectancy) [14]. These issues are discussed in detail separately. (See "Infections involving cardiac implantable electronic devices: Epidemiology, microbiology, clinical manifestations, and diagnosis" and "Cardiac implantable electronic device lead removal".) Lead failure The frequency of lead failure and the types of problems that occur have been evaluated in a number of studies [2,8-10,15-18]. Certain lead models and sizes have been identified as prone to failure [10,17,19]. Additionally, ICD leads seem more prone to failure compared with pacemaker leads, due to the increased complexity of the design to allow for both pacing and defibrillation functions. However, it is difficult to separate the relative contribution of materials, lead diameter, lead design, patient factors (eg, younger age, female sex, lower BMI, submuscular pectoral implant, etc) or other as yet unidentified factors with respect to failure rates. In a series of 1317 consecutive patients with an ICD placed between 1993 and 2004 who were followed for a median of 6.4 years, 38 patients (2.9 percent) experienced a lead malfunction requiring lead revision, with 29 of the 38 patients (76 percent) experiencing inappropriate ICD therapies [8]. The main reasons for lead malfunction were insulation defects (26 percent), artifact oversensing (24 percent), and lead fractures (24 percent). The rate of recurrent ICD lead- https://www.uptodate.com/contents/cardiac-implantable-electronic-devices-long-term-complications/print 3/22 7/6/23, 10:48 AM Cardiac implantable electronic devices: Long-term complications - UpToDate related problems was 20 percent at five years. Deaths related to ICD lead failure have been reported but are exceedingly rare [20]. Detecting lead failure Lead failure has traditionally most commonly been diagnosed when a patient presents with symptoms related to the failed lead (eg, inappropriate ICD shocks, dizziness or syncope due to failure to pace, etc) and the device parameters are interrogated. Evidence of lead fracture is rarely identified on a chest radiograph. With modern systems, remote CIED follow-up has frequently revealed evidence of lead malfunction before it is manifested clinically. Patients with known hardware under advisory should be followed with remote monitoring in order to detect potential lead failure as soon as possible [21]. Devices often have software designed to detect emerging lead problems [22]. For example, one manufacturer's algorithm that combines oversensing and impedance measurements to detect coaxial ICD lead failure found a sensitivity of 83 percent (24 of 29) and a specificity of 100 percent in 667 patients when tested in a population with various lead models [23]. The algorithm was subsequently modified to add features beyond lead failure detection, including a more extensive alerting system and the implementation of real-time, automatic changes to the ventricular fibrillation (VF) detection parameters of the ICD when a lead failure is detected [24]. (See "Cardiac implantable electronic device lead removal", section on 'Advisory/recall'.) Lead extraction When mechanical lead failure has been identified, lead replacement is indicated. The decision to remove a failed lead, versus capping the lead and leaving it in site (ie, abandoning the lead), is made on a case by case basis, with the decision largely dependent on the perceived risk/benefit ratio, both peri-procedural and long-term, in the individual patient. Indications and outcomes for lead extraction are discussed separately. Unfortunately, long-term follow-up data comparing outcomes in patients who undergo lead extraction versus capping and abandoning are not currently available. (See "Cardiac implantable electronic devices: Periprocedural complications" and "Cardiac implantable electronic device lead removal" and "Infections involving cardiac implantable electronic devices: Epidemiology, microbiology, clinical manifestations, and diagnosis".) Tricuspid regurgitation Severe tricuspid regurgitation (TR) can result from the placement of CIED leads causing damage to the tricuspid valve or impeding the appropriate closure of the valve during systole [25-27]. The frequency of developing significant TR is approximately 10 to 20 percent of persons receiving a CIED device with transvenous leads, ultimately resulting in heart failure symptoms in approximately 50 percent of those with severe TR [25]. In a single-center cohort study of 58,556 patients (including 634 with PPMs; patients with ICDs were excluded from this study) who underwent echocardiograms over a seven-year period from 2005 to 2011, 16 percent of patients with a PPM had severe TR, compared with 2 percent of patients without a https://www.uptodate.com/contents/cardiac-implantable-electronic-devices-long-term-complications/print 4/22 7/6/23, 10:48 AM Cardiac implantable electronic devices: Long-term complications - UpToDate PPM [28]. After adjusting for baseline comorbidities, significant TR remained significantly more likely in patients with a PPM (adjusted odds ratio 2.3, 95% CI 1.5-3.5). Tricuspid regurgitation has also been reported amongst recipients of bioprosthetic tricuspid valves who subsequently undergo implantation of a permanent pacemaker (PPM) or ICD with a transvenous ventricular lead. In a retrospective cohort study of 323 patients who received a bioprosthetic tricuspid valve (58 patients with a PPM/ICD lead, 265 patients without a lead) and were followed for a mean of over two years, there was a non-significant increase in the rate of moderate or severe TR in patients with a device lead (9 versus 5 percent), rates which compare favorably with the rate of TR development following transvenous lead placement through native tricuspid valves [29]. While the study is limited due to its retrospective, non-randomized nature, these results suggest that transvenous device leads are relatively safe and feasible in patients with a bioprosthetic tricuspid valve. As an alternative, leadless cardiac pacemakers can be considered in this population. (See "Permanent cardiac pacing: Overview of devices and indications", section on 'Leadless systems'.) Management of TR is discussed in detail separately. (See "Management and prognosis of tricuspid regurgitation", section on 'Management of pacemaker therapy'.) Increased defibrillation threshold The safety threshold values for pacing and defibrillation may change over time. Causes of both increased pacing and DFT include lead dislodgement/micro-dislodgement, inflammation around the tip, exit block, lead failure, progression of left ventricular dysfunction and left ventricle (LV) dilatation, and the effects of certain drugs. The DFT (also called defibrillation energy requirement for an ICD) is usually 15 joules and often <10 joules with biphasic shocks and improved lead systems. Routine DFT testing has not shown a clinical benefit in patients receiving an ICD for primary prevention. However, when the DFT is high, higher energy devices, reversed energy polarity, other waveform modifications, and/or alternative lead placements can be used to achieve an adequate safety margin. When these measures fail, an additional defibrillation lead can be placed in the azygous vein (posterior to the heart) to improve the shocking vector. Very rarely, placement of a tunneled subcutaneous array or an epicardial lead is required. Manipulation of pharmacologic therapy can also be helpful in selected cases; amiodarone is known to increase the defibrillation energy requirement (see below), while sotalol and dofetilide tend to lower this parameter. Frequent ICD discharges may produce a secondary increase in DFT due to intense fibrosis and cumulative damage at the ICD electrode-myocardial interface [30,31]. However, in the absence of any changes in the clinical status of the patient, DFTs with current transvenous lead systems are generally stable over time [32,33]. https://www.uptodate.com/contents/cardiac-implantable-electronic-devices-long-term-complications/print 5/22 7/6/23, 10:48 AM Cardiac implantable electronic devices: Long-term complications - UpToDate A more common problem is that patients with frequent appropriate shocks may be treated with amiodarone, which can increase the DFT and also alter the pacing threshold [34]. Older professional society guidelines for amiodarone therapy recommended that, whenever amiodarone was initiated in a patient with an ICD, a noninvasive ICD evaluation or an electrophysiology study should be performed to test for adverse drug-device interactions once loading is complete [35]. However, a 2015 expert consensus statement did not specifically address the role of DFT testing in patients treated with amiodarone; however, the consensus statement did indicate that it was "reasonable" to omit routine DFT testing for most newly implanted left pectoral ICD systems with right ventricular apical lead position as well as for high- risk patients with cardiac comorbidities such as severe pulmonary hypertension or severely depressed left ventricular function (eg, LVEF <20 percent) [36]. Data supporting this move away from DFT testing in patients receiving amiodarone were reported from the OPTIC trial, in which the increase in DFT related to amiodarone was quite small, calling into question the necessity of verifying the defibrillation safety margin [37]. (See "Implantable cardioverter-defibrillators: Overview of indications, components, and functions", section on 'Defibrillation threshold testing'.) PULSE GENERATOR COMPLICATIONS Long-term complications related to the CIED pulse generator are relatively uncommon, occurring in less than 2 percent of patients, and include skin erosion/infection, device and/or lead migration, tissue necrosis (due to the size and weight of the generator) and electromechanical interference/damage [2]. In addition, peri-procedural complications (eg, hematomas, infection) can occur in the pulse generator pocket [38]. (See "Cardiac implantable electronic devices: Periprocedural complications".) Pocket erosion/infection Infection involving the pulse generator pocket can occur at the time of CIED implantation or at any subsequent time. Because infection of a CIED can be a life- threatening problem, complete removal of the CIED pulse generator and all leads, along with antibiotic therapy, are strongly recommended. In rare instances, a patient may elect to pursue palliative antibiotic therapy; however, such an approach is not curative. These issues are discussed in detail separately. (See "Infections involving cardiac implantable electronic devices: Epidemiology, microbiology, clinical manifestations, and diagnosis" and "Cardiac implantable electronic device lead removal".) Pulse generator infection occurring late (more than six months post-implantation) may be due a chronic, smoldering infection, which can be subclinical for a prolonged period of time. These infections are more common with low virulence organisms such as coagulase negative https://www.uptodate.com/contents/cardiac-implantable-electronic-devices-long-term-complications/print 6/22 7/6/23, 10:48 AM Cardiac implantable electronic devices: Long-term complications - UpToDate Staphylococcus species. This can be associated with device erosion through the skin. Though rare, this particular complication is more common amongst thin patients with minimal subcutaneous fat and other tissue overlying the device. Significant weight loss after implant predisposes to this complication. Once the integrity of the skin overlying the device has been compromised, system infection should be assumed, even in the absence of symptoms, and the device (and frequently leads) will need to be removed and replaced. Repeated device infection should also raise concern for potential allergy to device components, which can rarely occur. In cases of suspected device component allergies, skin testing with specialized panels should be performed by a dermatologist or allergist. In patients who are at high risk for pocket infection, prophylactic use of a dissolving antibiotic pouch around the device may be useful. Randomized clinical trials are underway to test the efficacy of such an approach [39]. Twiddler's syndrome Twiddler's syndrome is a condition in which twisting or rotating the CIED pulse generator within its pocket results in lead dislodgement and device malfunction [40,41]. Affected patients most often present with an increase in bradycardic pacing threshold or lead impedance, although pacemaker-dependent patients may present with symptoms related to bradyarrhythmia (eg, syncope, lightheadedness, etc). In patients with ventricular lead dislodgement and retraction, it is also possible that an ICD will fail to sense and treat an arrhythmia. Careful suturing of the lead suture sleeves, suturing the device to the fascia, using a nonabsorbable antimicrobial pouch, warning the patient not to manipulate the device, and ensuring appropriate pocket size are important proactive steps to reduce the likelihood of this complication [42]. Electronic circuit damage Device failures are uncommon, with reports estimating an incidence between 0.01 and 0.1 percent [43]. Electronic circuit failure can result from electrical overstress damage to the high voltage hybrid circuit and other electronic components [44]. Signs of such failure include loss of telemetry and inability to deliver therapy. Electrical overstress damage may occur during capacitor reformation or charging and the delivery of a shock, after cardioversion, or rarely with the use of electrocautery. It is recommended that routine follow-up examination of device function be performed in these settings. Radiation therapy can damage circuitry as well. Current recommendations include shielding the device from the radiation beam and careful follow-up, particularly in pacemaker-dependent patients. In some instances, it may be required to relocate the pulse generator outside of the radiation field. Electromagnetic interference Since reliable function of any CIED depends upon proper sensing of the electrical activity of the heart, a potential concern is electromagnetic interference from external sources, including cellular telephones containing magnets, welding equipment, https://www.uptodate.com/contents/cardiac-implantable-electronic-devices-long-term-complications/print 7/22 7/6/23, 10:48 AM Cardiac implantable electronic devices: Long-term complications - UpToDate motor-generator systems, and surveillance systems ( table 1). These issues are discussed in detail separately. (See "Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment".) Interference with ICD function can occur during noncardiac surgery as a result of electrical current generated by electrocautery, as well as during magnetic resonance imaging (MRI). Issues related to electrosurgery and MRI scanning and potential interactions with implanted cardiac devices are discussed in detail separately. (See "Perioperative management of patients with a pacemaker or implantable cardioverter-defibrillator".) Advisories/recalls Occasionally, CIED manufacturers will issue an "advisory" or "recall" due to concerns about device performance or safety. In most instances following a notification, CIED failure rates are quite low, but some patients/physicians choose to electively replace generators on a case by case basis. ARRHYTHMIC COMPLICATIONS A variety of arrhythmia-related problems can occur in patients with an ICD. Arrhythmic complications include both inappropriate shocks, usually due to the treatment of supraventricular tachycardias, and appropriate shocks. Additionally, while not caused by an arrhythmia, the perception of a shock when one has not been delivered, termed a "phantom shock," should be considered in patients with symptoms but no evidence of shock on device interrogation. Inappropriate shocks Inappropriate shocks (ie, shocks delivered by an ICD for any rather other than ventricular tachyarrhythmia) occur in up to 40 percent of patients with an ICD [45-50]. However, contemporary device programming, including delayed detection and use of discriminator functions, is associated with lower risks of inappropriate shocks [51]. The most common cause of inappropriate shocks is a supraventricular tachyarrhythmia (SVT), which results in a ventricular heart rate that falls within a programmed treatment zone [46,50]. The most common supraventricular arrhythmia causing inappropriate therapies is atrial fibrillation, although sinus tachycardia and other SVTs may also result in inappropriate shocks. Other causes of inappropriate shocks include electrical noise, inappropriate sensing (ie, T wave oversensing), and ICD malfunction (typically due to lead fracture). Patients who receive inappropriate shocks may become quite anxious or uncomfortable since the most common causes of inappropriate shocks (ie, SVT and lead fracture) often result in the delivery of multiple shocks. Rarely, multiple inappropriate (or even appropriate) shocks can result in a posttraumatic-stress-disorder-like syndrome. https://www.uptodate.com/contents/cardiac-implantable-electronic-devices-long-term-complications/print 8/22 7/6/23, 10:48 AM Cardiac implantable electronic devices: Long-term complications - UpToDate While inappropriate shocks due to lead fracture or other device malfunction are difficult to predict (and therefore prevent), the frequency of inappropriate shocks not related to lead malfunction (ie, those related to SVT) can usually be reduced with modern ICD programming strategies. The recommended modern approach to ICD programming is discussed in detail separately. In addition to modern device programming (eg, high rate cutoffs, longer delays prior to initiating treatment), other device features such as arrhythmia discrimination and the placement of an atrial lead may reduce the frequency of inappropriate shocks [21,52]. Dual-chamber devices have an atrial lead for sensing, which allows for more effective discrimination between atrial and ventricular arrhythmias, with appropriate programming, dual-chamber ICDs have been shown to decrease inappropriate detection compared with single-chamber devices [53]. However, device programming to limit unnecessary therapies may be more important than dual-chamber devices [54]. Modern devices nearly universally contain proprietary arrhythmia discrimination software, which aims to accurately discriminate between various atrial tachyarrhythmias (eg, atrial tachycardia, atrial flutter, and atrial fibrillation) and ventricular tachyarrhythmias. While there are conflicting data on an association between inappropriate shocks and mortality, most studies suggest a 1.5-to-2-fold increase in mortality among recipients of an inappropriate shock [46-48,55]. As an example, among patients in the ALTITUDE study who received inappropriate shocks, those who were shocked for atrial fibrillation or atrial flutter had significantly increased mortality (hazard ratio [HR] 1.6 compared with those without any ICD shock), while those who were shocked for other supraventricular tachyarrhythmias or sinus tachycardia had no difference in mortality (HR 1.0 compared with no ICD shock) [50]. Appropriate shocks Appropriately-delivered ICD shocks for ventricular tachyarrhythmias are not technically a complication but rather the intended response of the device. While potentially life-saving, appropriate shocks can also have an adverse effect on quality of life, including emotional problems and driving restriction. (See 'Quality of life' below and "Driving restrictions in patients with an implantable cardioverter-defibrillator", section on 'Overall incidence of ventricular arrhythmias and ICD shocks'.) In a systematic review of seven trials of primary and secondary prevention of sudden cardiac death (SCD), appropriate ICD therapies outnumbered SCD events in the control groups by a factor of two to three [56]. Subsequent studies have clarified that the likely reason for this discrepancy in outcomes relates to the treatment of arrhythmias that would have been hemodynamically tolerated and/or terminated spontaneously (ie, nonfatal events). Strategies to https://www.uptodate.com/contents/cardiac-implantable-electronic-devices-long-term-complications/print 9/22 7/6/23, 10:48 AM Cardiac implantable electronic devices: Long-term complications - UpToDate reduce the number of appropriate shocks include high rate cutoffs for delivering a shock, longer delays prior to initiating treatment, and antitachycardia pacing (ATP), which should terminate at least 90 percent of episodes of persistent VT [57,58]. Antitachycardia pacing as well as the recommended modern approach to ICD programming are discussed in detail separately. Phantom shocks The perception of having received an ICD shock when no shock was delivered is called a "phantom shock." In the prospective COPE-ICD trial, 9 percent of patients reported phantom shocks [59]. While the underlying reason for experiencing a phantom shock is not known, patients who do report phantom shocks are more likely to have received an actual ICD shock (and thus may have continued worry about receiving another shock) or to suffer from unrelated anxiety or depression [60,61]. The optimal strategy to manage phantom shocks depends on the patient. For those who have continued worry about phantom shocks, counseling or pharmacotherapy may be necessary to address the patient's anxiety. For some patients, careful follow-up or transtelephonic monitoring may be valuable. Frequent follow-up and further discussions with the electrophysiologist may be necessary, but over time, symptoms tend to abate without the need for unnecessary interventions or the need to turn the device off. MISCELLANEOUS COMPLICATIONS Heart failure CIEDs may worsen left ventricular function and/or precipitate symptomatic heart failure (HF), particularly in patients with preexisting systolic dysfunction, by one of two mechanisms: Right ventricular pacing, producing ventricular dyssynchrony. Improved long-term survival in patients with advanced cardiac disease can result in patients living long enough for HF to develop or progress. These issues are discussed in detail separately. (See "Modes of cardiac pacing: Nomenclature and selection", section on 'Modes to minimize ventricular pacing' and "Overview of pacemakers in heart failure", section on 'Implantable cardioverter-defibrillators'.) Quality of life The ICD is often associated with deleterious psychosocial effects, with as many as 50 percent of recipients reporting elevated levels of anxiety and depression resulting from the fear of receiving a shock, device failure, decrease in physical activity, and negative lifestyle changes (such as the inability to drive or to return to work) [62-70]. Some patients develop severe psychiatric problems after receiving appropriate shocks [71]. https://www.uptodate.com/contents/cardiac-implantable-electronic-devices-long-term-complications/print 10/22 7/6/23, 10:48 AM Cardiac implantable electronic devices: Long-term complications - UpToDate The frequency and severity of these psychosocial effects can be illustrated by the following findings: In a report of 119 patients, most described the shocks from the ICD as severe [62]. Common descriptions were a blow to the body or a spasm causing the body to jump. Twenty-three percent dreaded the shocks, and 5 percent said they would prefer to be without the ICD and take their chances. However, most patients tolerated the shocks because they are lifesaving. Another study of 70 patients noted an association between the number of shocks received and the likelihood of mood disturbances, ranging from 9 percent among those with less than four shocks to 55 percent in those with more than 10 shocks [63]. In an analysis of 800 patients from the AVID trial of secondary prevention, the ICD and amiodarone were associated with similar alterations in quality of life [66]. A reduction in physical functioning and mental well-being was largely related to the occurrence of any shocks from the ICD and to adverse side effects from the ICD or drug. Efforts should be made to reduce the frequency of both appropriate and inappropriate shocks if they are common enough to interfere with the quality of life. The degree of anxiety and depression can also be reduced by the use of group and individual support and behavioral, cognitive, and relaxation therapies [72,73]. (See 'Appropriate shocks' above and 'Inappropriate shocks' above.) The safety of driving in patients with an ICD is discussed separately. (See "Driving restrictions in patients with an implantable cardioverter-defibrillator".) INFORMATION FOR PATIENTS UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." th th The Basics patient education pieces are written in plain language, at the 5 to 6 grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more th th sophisticated, and more detailed. These articles are written at the 10 to 12 grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon. https://www.uptodate.com/contents/cardiac-implantable-electronic-devices-long-term-complications/print 11/22 7/6/23, 10:48 AM Cardiac implantable electronic devices: Long-term complications - UpToDate Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.) Basics topics (see "Patient education: Sudden cardiac arrest (The Basics)") Beyond the Basics topics (see "Patient education: Implantable cardioverter-defibrillators (Beyond the Basics)") SUMMARY AND RECOMMENDATIONS Lead-related problems include infection, lead failure (resulting in failure to pace, failure to shock, or inappropriate shocks), tricuspid valve damage, venous thrombosis, and increased defibrillation thresholds. Infection of the generator pocket or leads can occur at the time of CIED implantation or at any subsequent time. Because infection of a CIED can be a life-threatening problem, complete removal of the CIED pulse generator and all leads, along with antibiotic therapy, are strongly recommended for nearly all patients. (See 'Infection' above and "Infections involving cardiac implantable electronic devices: Epidemiology, microbiology, clinical manifestations, and diagnosis" and "Cardiac implantable electronic device lead removal".) Lead failure, which has had a highly variable frequency from lead to lead, has traditionally most commonly been diagnosed when a patient presents with symptoms related to the failed lead (eg, inappropriate implantable cardioverter-defibrillator [ICD] shocks, dizziness or syncope due to failure to pace, etc) and the device parameters are interrogated. When mechanical lead failure has been identified, lead replacement is indicated. (See 'Lead failure' above.) Severe tricuspid regurgitation (TR) can result from the placement of CIED leads causing damage to the tricuspid valve or impeding the appropriate closure of the valve during systole. (See 'Tricuspid regurgitation' above.) The safety threshold values for pacing and defibrillation may change over time. Causes of both increased pacing and defibrillation threshold include lead dislodgement/micro- dislodgement, inflammation around the tip, exit block, lead failure, progression of left ventricular dysfunction and dilatation, and the effects of certain drugs. (See 'Increased defibrillation threshold' above.) https://www.uptodate.com/contents/cardiac-implantable-electronic-devices-long-term-complications/print 12/22 7/6/23, 10:48 AM Cardiac implantable electronic devices: Long-term complications - UpToDate Long-term complications related to the CIED pulse generator are relatively uncommon, occurring in less than 2 percent of patients, and include skin erosion/infection, device and/or lead migration, tissue necrosis (due to the size and weight of the generator) and electromechanical interference/damage. (See 'Pulse generator complications' above and "Cardiac implantable electronic device interactions with electromagnetic fields in the nonhospital environment", section on 'Equipment with high-strength magnets'.) A variety of arrhythmia-related problems can occur in patients with an ICD. Arrhythmic complications include both inappropriate shocks, usually due to the treatment of supraventricular tachycardias, as well as appropriate shocks and "phantom" shocks. Inappropriate shocks (ie, shocks delivered by an ICD for any rather other than ventricular tachyarrhythmia) occur in up to 40 percent of patients with an ICD. The frequency of inappropriate shocks not related to lead malfunction (ie, those related to supraventricular tachycardia [SVT]) can usually be reduced with modern ICD programming strategies. (See 'Inappropriate shocks' above.) Appropriately-delivered ICD shocks for ventricular tachyarrhythmias are not technically a complication but rather the intended response of the device. While potentially life- saving, appropriate shocks can also have an adverse effect on quality of life, including emotional problems and driving restriction. (See 'Appropriate shocks' above.) The perception of having received an ICD shock when no shock was delivered is called a "phantom shock." The optimal strategy to manage phantom shocks depends on the patient, but typically involves close follow-up and reassurance. (See 'Phantom shocks' above.) ACKNOWLEDGMENT The UpToDate editorial staff acknowledges Leonard Ganz, MD, FHRS, FACC, who contributed to an earlier version of this topic review. Use of UpToDate is subject to the Terms of Use. REFERENCES 1. Pfeiffer D, Jung W, Fehske W, et al. Complications of pacemaker-defibrillator devices: diagnosis and management. Am Heart J 1994; 127:1073. https://www.uptodate.com/contents/cardiac-implantable-electronic-devices-long-term-complications/print 13/22 7/6/23, 10:48 AM Cardiac implantable electronic devices: Long-term complications - UpToDate 2. Kron J, Herre J, Renfroe EG, et al. Lead- and device-related complications in the antiarrhythmics versus implantable defibrillators trial. Am Heart J 2001; 141:92. 3. DiMarco JP. Implantable cardioverter-defibrillators. N Engl J Med 2003; 349:1836. 4. Ranasinghe I, Parzynski CS, Freeman JV, et al. Long-Term Risk for Device-Related Complications and Reoperations After Implantable Cardioverter-Defibrillator Implantation: An Observational Cohort Study. Ann Intern Med 2016. 5. Kipp R, Hsu JC, Freeman J, et al. Long-term morbidity and mortality after implantable cardioverter-defibrillator implantation with procedural complication: A report from the National Cardiovascular Data Registry. Heart Rhythm 2018; 15:847. 6. Hawkins NM, Grubisic M, Andrade JG, et al. Long-term complications, reoperations and survival following cardioverter-defibrillator implant. Heart 2018; 104:237. 7. Maisel WH. Pacemaker and ICD generator reliability: meta-analysis of device registries. JAMA 2006; 295:1929. 8. Eckstein J, Koller MT, Zabel M, et al. Necessity for surgical revision of defibrillator leads implanted long-term: causes and management. Circulation 2008; 117:2727. 9. Maisel WH, Kramer DB. Implantable cardioverter-defibrillator lead performance. Circulation 2008; 117:2721. 10. van Rees JB, van Welsenes GH, Borleffs CJ, et al. Update on small-diameter implantable cardioverter-defibrillator leads performance. Pacing Clin Electrophysiol 2012; 35:652. 11. Nazarian S, Hansford R, Rahsepar AA, et al. Safety of Magnetic Resonance Imaging in Patients with Cardiac Devices. N Engl J Med 2017; 377:2555. 12. Russo RJ, Costa HS, Silva PD, et al. Assessing the Risks Associated with MRI in Patients with a Pacemaker or Defibrillator. N Engl J Med 2017; 376:755. 13. Zuber M, Huber P, Fricker U, et al. Assessment of the subclavian vein in patients with transvenous pacemaker leads. Pacing Clin Electrophysiol 1998; 21:2621. 14. Nishimura RA, Otto CM, Bonow RO, et al. 2017 AHA/ACC Focused Update of the 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol 2017; 70:252.