Implantable Cardioverter Defibrillator Complications Research Articles

Psychological Wellbeing and Posttraumatic Stress Associated with Implantable Cardioverter Defibrillator Therapy in Young Adults with Genetic Heart Disease

Abstract Background Sudden cardiac death is a tragic complication of a number of genetic heart diseases. Implantable cardioverter defibrillator (ICD) therapy plays an important role in prevention of sudden death. The psychological consequences of ICD therapy in young people with genetic heart disease are poorly understood. This study sought to better understand psychological wellbeing and identify symptoms of posttraumatic stress in young people who had experienced an ICD shock. Methods Eligible patients (ICD implanted over 12months prior) with an inherited cardiomyopathy or primary arrhythmogenic disorder, enrolled in the Australian Genetic Heart Disease Registry were included. Ninety patients completed the Hospital Anxiety and Depression Scale (HADS). Those patients who had an ICD shock (n=31) also completed the Impact of Events Scale-Revised (IES-R). Results While the mean HADS-Anxiety and IES-R scores were within the normal range in the total group (n=90), a significant subgroup reported symptoms of anxiety (38%), depression (17%) and posttraumatic stress (31%) indicative of the potential need for referral to clinical care. Overall, greater psychological distress in ICD patients was associated with female gender, a history of syncope, other comorbid medical conditions, and reporting of other distressing events (i.e., ICD complications). In those with an ICD shock, higher posttraumatic stress scores were associated with female gender and longer time to first shock. Conclusions Patients with genetic heart diseases can experience psychological difficulties, including anxiety, depression and posttraumatic stress, related to ICD implantation and subsequent shocks. This signals the importance of offering patients access to targeted interventions, including psychological care and support.

EComment. Surgical complications of permanent cardiac pacemaker insertion

We read with interest the manuscript by Wu and Chen and we would like to comment on the surgical complications of intracardiac pacemaker implantation [1]. The use of permanent pacemakers (PPM) and implantable cardioverter-defibrillators (ICD) is increasing due to the expansion of indications and aging of the population. As a consequence, cardiologists and cardiothoracic surgeons have to deal with a broad spectrum of complications, which are sometimes under-estimated and life-threatening. The surgical complications of PPM and ICD may occur during the immediate or early post-operative period and can be related to venous access process (pneumothorax, hemothorax, air embolism, haematoma, arterial puncture, wound healing problems, infection, pain), to the pacemaker lead (cardiac perforation, tamponade, malposition or dislodgement of the lead), or to the generator device. In addition, other complicationed that may occur during the late post-operative period are related to infections, thrombosis, endocarditis, pulmonary embolism, superior vena cava (SVC) syndrome (due to thrombus formation and/or fibrosis of the pacing wires within the SVC) and pericarditis [2-5]. Ostovan and Aslani have reported on the successful treatment of massive pulmonary air embolism during a PPM implantation with air suctioning by the guide catheter inserted into main pulmonary artery via the left femoral vein. Treatment for air embolisms includes oxygen treatment, haemodynamic support and prevention of further air entry in the systemic circulation. The left lateral decubitus position can prevent the air obstruction of the pulmonary outflow tract (air can be moved toward the right ventricular apex) [2]. Aggarwal et al. found no difference in the incidence of intraoperative and early postoperative complications (up to two months after implantation) between single and dual chamber pacing systems [3]. Sohail et al., in their retrospective review of 189 patients with pacemaker related infections, found out that the most common clinical presentations were generator pocket infection (69%) and device-related endocarditis (23%). The leading pathogens were Coagulase-negative Staphylococci and Staphylococcus aureus, in 42% and 29% of cases, respectively. There was a broad spectrum of related complications such us septic arthritis, sternal or vetebral or femoral osteomyelitis, and abscesses in lung, spleen, liver, brain and perinephric area. Twenty-two (11.6%) patients had thrombosis of the subclavian vein or superior vena cava and 6 of them developed clinical manifestations of pulmonary embolism. Ninety-eight percent of patients underwent complete device removal combined with antibiotic treatment and 96% of patients were treated successfully [4]. Nineteen patients had lead extraction via a median sternotomy and the rest underwent percutaneous lead extraction. Interventional complications were more common in patients with a history of multiple device-related procedures and were related to tricuspid valve failure, laceration of subclavian vein, hemothorax, haematoma, fracture of lead tip, ventriculotomy and bleeding [4]. Right atrial thrombosis and pulmonary embolism are infrequent complications (0.6%-3.5%) and its therapeutic modalities include anticoagulation, thrombolysis and or surgery [5]. In conclusion, the knowledge of all potential complications of the PPM/ICD and its multidisciplinary approach is very important for its prevention and definitive treatment. Conflict of interest: none declared

Outcome and Complications After Implantable Cardioverter Defibrillator Therapy in Hypertrophic Cardiomyopathy

Background— Previous observational studies demonstrated that patients with hypertrophic cardiomyopathy at risk for sudden cardiac death (SCD) may benefit from implantable cardioverter defibrillator (ICD) therapy. A complete overview of outcome and complications after ICD therapy is currently not available. This study pools data from published studies on outcome and complications after ICD therapy in patients with hypertrophic cardiomyopathy. Methods and Results— A PubMed database search returned 27 studies on 16 cohorts reporting outcome and complications after ICD therapy in patients with hypertrophic cardiomyopathy. In case of >1 publications on a particular cohort, the publication with the largest number of patients was included in the meta-analysis. ICD interventions, complications, and mortality rates were extracted, pooled, and analyzed. There were 2190 patients (mean age, 42 years; 38% women), most of whom (83%) received an ICD for primary prevention of SCD. Risk factors for SCD were left ventricular wall thickness ≥30 mm (20%), family history of SCD (43%), nonsustained ventricular tachycardia (46%), syncope (41%), and abnormal blood pressure response (25%). During the 3.7-year follow-up, the annualized cardiac mortality rate was 0.6%, the noncardiac mortality rate was 0.4%, and the appropriate ICD intervention rate was 3.3%. The annualized inappropriate ICD intervention rate was 4.8% and the annualized ICD-related complication rate was 3.4%. Conclusions— This meta-analysis demonstrates a low cardiac and noncardiac mortality rate after ICD therapy in patients with hypertrophic cardiomyopathy. Appropriate ICD intervention occurred at a rate of 3.3%/year, thereby, most probably, preventing SCD. Inappropriate ICD intervention and complications are not uncommon.

Risk Stratification and Therapeutic Approach in Brugada Syndrome.

Brugada syndrome (BrS) is a clinical entity characterised by an incomplete right bundle branch block associated with an ST segment elevation in the right precordial leads and a risk of ventricular arrhythmia and sudden death in the absence of structural abnormalities. Patients with a personal history of sudden death have an annual arrhythmia risk of recurrence as high as 10 %. Similarly, the presence of syncope is consistently associated with an increased arrhythmic risk. This risk can be estimated at about 1.5 % per year. The risk is lower in asymptomatic patients. Regarding the relatively high rate of complication of Implantable cardioverter defibrillator (ICD) implantation, in most of the cases, asymptomatic patients with a Brugada syndrome revealed during ajmaline challenge do not need to be implanted. The situation is more complex in patients with a spontaneous type 1 aspect since the risk could be estimated to be around 0.8 % per year. For these patients, a careful evaluation of the arrhythmic risk using all the different tools available is mandatory.

Implantation of a completely subcutaneous ICD system: case report of a patient with Brugada syndrome and state of the art

Complications of implantable cardioverter-defibrillator (ICD) therapy are often linked to transvenous lead insertion, lead failure, or infections. An entirely subcutaneous ICD system (S-ICD) avoids the need for the placement of electrodes within the heart and can provide clinical advantages. A 45-year-old patient with Brugada syndrome (spontaneous type 1 Brugada ECG, syncope during fever, family history of sudden death <45 years old) was implanted with an entirely S-ICD. A left lateral incision was made over the sixth rib in the anterior axillary line for pocket formation and pulse generator placement. The subcutaneous electrode was placed subcutaneously, parallel to and 2 cm to the left of the sternal midline, and was connected to the generator. The insertion of the system was guided only by anatomical landmarks, and no fluoroscopy was required. Ventricular fibrillation was induced and terminated by a 65-J shock (15-J safety margin). No complication occurred, and subsequent course was uneventful. S-ICD is a new system for delivering lifesaving shock therapy in patients at risk of sudden cardiac death, without the need of intracardiac leads. Young patients with inherited arrhythmogenic syndromes could benefit the most from this system. This is the first case of Brugada syndrome implanted with a first-generation S-ICD in Italy.

Use of implantable cardioverter-defibrillators for primary prevention in older patients: A systematic literature review and meta-analysis

Randomized clinical trials (RCTs) have demonstrated the efficacy of implantable cardioverter-defibrillators (ICDs) in reducing sudden cardiac death (SCD) in specific patient populations. However, patients ≥ 65 years were under-represented in these trials and the overall benefit of ICDs may be diminished in older patients due to competing risks for death. We evaluate the published data on ICD efficacy at reducing all-cause mortality in patients ≥ 65 years and in patients ≥ 75 years. We searched MEDLINE to identify RCTs and observational studies of ICDs that provided age-based outcome data for primary prevention of SCD. The primary endpoint was mortality evaluated by a meta-analysis of the RCTs using a random-effects model. Secondary endpoints included operative mortality, long-term complications and quality of life. The enrollment of patients ≥ 65 years in RCTs was limited (range: 33% in DEFINITE to 56% in MUSTT). Combining data from four RCTs (n = 3,562) revealed that primary prevention ICD therapy is efficacious in reducing all-cause mortality in patients ≥ 65 years (HR 0.66; 95% CI 0.50-0.87; test of heterogeneity: X(2) = 5.26; p = 0.15). For patients ≥ 75 years, combining data from four RCTs (n = 579) revealed that primary prevention ICD therapy remains efficacious in reducing all-cause mortality (HR 0.73; 95% CI 0.51-0.974; p = 0.03). There appears to be no difference in ICD-related, operative, in-hospital, or long- -term complications among older patients compared to younger patients, although it remains unclear if older patients have a better quality of life with an ICD than younger patients. Although the overall evidence regarding ICD efficacy in patients ≥ 65 years is limited and divergent, and the evidence available for patients ≥ 75 years is even more sparse, our meta-analysis suggests that primary prevention ICDs may be beneficial in older patients. Our findings need to be validated by future studies, particularly ones examining ICD complications and quality of life.

157 An insight into implanters' practices of ICD implantation: a physician survey

Introduction The Implantable cardioverter defibrillator (ICD) is the mainstay of treatment for the prevention of sudden cardiac death (SCD) and the management of tachyarrhythmias. Informed patient consent is an essential part of the implant process. Our aim was to get an insight into implanters9 (Imp) practices prior to an ICD implantation. Methods A questionnaire survey was sent to UK ICD Imp to test their knowledge of the risk and benefits of an ICD in patients who satisfy trial and national guideline criteria and the incidence of implant complications. Information of the style and language of consent was requested. This questionnaire was specifically aimed at Imp and was part of the larger questionnaire looking at knowledge, attitudes and factors influencing ICD prescription in the UK. Results Replies were received from 23 implanters. 35% of the responders were between the age of 30–39 years and 39% were between 40 and 49 years. 83% of the responders were Consultants and 96% were working in an implantating centre. 83% of Imp were fully aware of Primary Prevention (PP) NICE guidelines while 78% were fully aware of Secondary Prevention (SP) NICE guidelines. There was widespread use of information leaflets (87%) and specialist ICD nurses (83%) to disseminate information to patients. All responders said they would personally discuss the therapy with the patient prior to the implantation regardless of the referral source. A discussion regarding the prevention of SCD, inappropriate shocks and driving restrictions were performed by 96% of responders and device infections and lead failures discussed by 91%. Use of absolute risk reduction in percentages and number needed to treat while explaining the risks and benefits gained from ICDs were used by 22% and 26% respectively. There was widespread use of phrases like “small risk” or “moderate risk” (61%) and life prolongation (eg, lets you live longer by an average of 3 months) (30%). Replies also indicated that Imp under-estimate overall mortality in medicallytreated and ICD-treated patients, lead dislodgement requiring re-positioning and major haematoma requiring reoperation. Imp overestimate infections leading to device removal and the incidence of pneumothorax when compared to published trial or study data. Conclusion The majority of implanters are aware of UK ICD guidelines. The patient consent process is not universal. Guidelines and awareness about end-of-life care in ICD patients is needed and should be part of the initial consent process. Evidence based use of risk and benefit terminologies like ARR and NNT are needed to better inform the patient rather than abstract phrases. Increasing awareness of ICD complication rates can help patients and physicians balance risk against benefit which could lead to improved patient satisfaction with their therapy.

150 Implantable cardioverter-defibrillator lead complications and clinical effectiveness in patients with inherited cardiac conditions

<h3>Background</h3> Implantable cardioverter-defibrillator (ICD) therapy can reduce sudden death due to ventricular arrhythmia (VT/VF) but is not without complication, particularly in young patients who live for many years with a device in situ. We aimed to determine the ICD complication rate in our inherited cardiac condition (ICC) population compared with international reports. Particular importance was given to inappropriate shock therapy due to lead failure as there are new ICD technologies available. <h3>Methods</h3> Patients with ICCs who had ICD implantation or box change between January 2006 and September 2009 were included. Data on clinical characteristics, complications and ICD therapies were obtained from pacing and hospital records. We compared our data with several ICD studies of patients with specific ICCs (Abstract 150 table 1). <h3>Results</h3> 101 patients (mean age 44.1±14.8 years; 59 male) were included (idiopathic VF 15%; DCM 17%; ARVC 22%; HCM 21%; long QT syndrome 17%; Brugada syndrome 6%; others 2%). During a mean follow-up of 74.0±53.2 months 2 patients died (1 inappropriate shocks; 1 stroke). Indications were secondary prevention in 71.3% of patients. ICD types were 56.4% single chamber; 39.6% dual chamber; 4.0% biventricular. Appropriate therapy successfully terminated VT/VF in 27 (26.7%) patients 34.7% of secondary and 6.9% of primary prevention patients received appropriate therapy. Inappropriate therapy occurred in 18 (17.8%) patients and lead failure (noise/wear/fracture) in 22 (20.8%) patients (Abstract 150 table 2). 12 out of 18 inappropriate shocks were due to lead failure, 5 sensing errors (1 T-wave oversensing; 4 AF), 1 generator fault. 10/22 leads that failed were Medtronic Sprint Fidelis and these were responsible for 8/12 patients receiving inappropriate shocks including one death due to lead fracture. Comparison with other studies indicates a high lead failure rate due to the long follow-up period, similar to the LQT Study which reports 25% lead failure over 87 months (Abstract 150 table 1). With lead failure excluded the complication rate is comparable to shorter follow-up studies. Inappropriate and appropriate therapy rates are similar among all studies. <h3>Conclusions</h3> There is a significant rate of ICD lead failure in patients with ICCs, which may be expected given the high frequency of Sprint Fidelis leads implanted during this period and the long follow-up. Our results compare favourably to other similar studies. The high rate of appropriate therapy highlights the clinical effectiveness of ICD intervention in secondary prevention. Lead complications may be lower with the use of new ICD technology in selected patients.

Rhetorical Strategies Used in the Reporting of Implantable Defibrillator Primary Prevention Trials

Previous studies have suggest that the authors of randomized trial reports frequently use rhetorical strategies, such as framing, the use of ratios rather than absolute values to report results, and underreporting of complications, to convince readers of treatment efficacy. The objective of this study was to determine if such rhetorical strategies were used in the publication of implantable-cardioverter defibrillator (ICD) primary prevention trials. Medline and the Cochrane Central Register of Controlled Trials were searched for all publications that described ICD primary prevention trials and that involved >100 subjects. Each publication was analyzed for evidence of message framing, the exclusive use of ratios to report outcomes, underreporting of ICD complications, and interpretation bias favoring ICD therapy. Ten publications were identified. Introductory remarks in 8 of the 10 publications cited the evaluation of ICD benefits as the sole objective and mentioned only background studies that supported ICD efficacy, suggesting message framing in support of ICD efficacy. Five publications provided no specific information about the frequency of unsuccessful ICD implantations, and 8 publications provided incomplete or no information about implantation and postimplantation complications. ICD complications were not mentioned in the discussion sections of 9 publications, and none of the publications included a comprehensive comparison of ICD benefits versus risks, consistent with interpretation bias. Ratios and statistically insignificant data were not used to emphasize ICD benefits. In conclusion, message framing, underreporting of ICD complications, and interpretation bias were used to emphasize ICD efficacy in the reporting of ICD primary prevention trials.

Implantable Cardioverter Defibrillator‐Related Complications in the Pediatric Population

The recognition that implantable cardioverter-defibrillator (ICD) therapy in children can prolong life coupled with the development of smaller devices and transvenous lead technology has increased the number of ICDs implanted in children and young adults. ICD complications in the pediatric population are reviewed. ICD complications in the pediatric population include those related to the implantation procedure, the ICD system, as well as psychosocial issues. Inappropriate ICD therapy and ICD lead failures are the most frequent complications. Identifying complications is the prerequisite for advances in ICD technology and effective management strategies need to be developed to avoid their recurrence.

Potential role of home monitoring to reduce inappropriate shocks in implantable cardioverter-defibrillator patients due to lead failure

Lead dysfunctions in implantable cardioverter-defibrillator (ICD) patients can lead to inappropriate shocks or even complete loss of function of the device. Home monitoring (HM) systems are capable of daily data transmissions regarding the device and the lead integrity as well as information concerning anti-arrhythmic therapies. We therefore analysed the data from the Biotronik HM system whether it enables physicians to react quickly on serious ICD malfunctions and to avoid inappropriate shocks. Fifty-four patients who had to undergo resurgery due to malfunctions of the ICD lead were included. Eleven of them were on HM interrogating the device every night at 3 am. If any adverse event was detected, a fax alert was sent to the clinic and the patients were asked for in-hospital ICD interrogation. The rate of inappropriate shocks and symptomatic pacemaker inhibition due to oversensing was compared with the 43 patients without remote surveillance. HM sent alert messages in 91% of all incidents. All lead failures became obvious because of oversensing of high frequency artefacts. Only in 18%, changes in the pacing impedance were noticed, in all cases preceded by oversensing. Eighty per cent of the patients were asymptomatic at the first onset of oversensing. Only one patient suffered an inappropriate shock as first manifestation of lead failure. Compared with the patients without HM, inappropriate shocks occurred in 27.3% in the HM group vs. 46.5% (P = n.s.). This trend gains statistical significance, if the compound endpoint of symptomatic lead failure consisting of inappropriate shocks and symptomatic pacemaker inhibition due to oversensing is focused: 27.3% event in the HM group vs. 53.4% in the group without HM (P = 0.04). Event messages were despatched in a mean of 54 days after the last ICD interrogation and 56 days before next scheduled visit. Thus, 56 days of reaction time are gained to avoid adverse events. In 91% of all lead-related ICD complications, the diagnosis could be established correctly by an alert of the HM system. Mostly, the first incident sent was oversensing of artefacts, falsely detected as ventricular fibrillation-the VF zone. The automatic HM surveillance system enables physicians to detect severe lead problems early and to react quickly; thus, it might have a potential to avoid inappropriate shocks due to lead failure and T-wave oversensing.

The Innominate Vein as Alternative Venous Access for Complicated Implantable Cardioverter Defibrillator Revisions

Venous complications of implantable cardioverter defibrillator (ICD) systems may cause significant problems when the need for system revision or upgrades arises. Such revisions require venous access close to the site of the previous ICD implantation. The internal and external jugular vein have disadvantages due to a long subcutaneous course crossing the clavicle and problems with lead extraction if infection occurs. In seven patients with ICD revisions due to lead dysfunction (n = 4) and upgrade to a biventricular device (n = 2) and status after system removal due to infection with new device implantation (n = 1) conventional venous access could not be obtained. Intraoperative contrast venography demonstrated an occluded left subclavian and/or left innominate vein in all patients. In all patients, we gained venous access through puncture of the right innominate vein and tunneled the new lead subcutaneously to the ICD pocket on the left. No intraoperative complications were observed. All patients are followed in our ICD clinic. Mean follow-up is 16 +/- 4 months now. So far, no clinical or lead complications with this access have been observed. We have demonstrated that ICD lead placement through puncture of the right innominate vein is feasible. We propose the innominate vein as an alternative route for establishing venous access in patients requiring ICD revisions or upgrades who suffer from venous obstruction. ICD implanting physicians should acquaint themselves with the technique of right innominate vein puncture to use this vein as a bail-out strategy in patients with complicated venous access.

Implantable Cardioverter-Defibrillators and Prevention of Sudden Cardiac Death in Hypertrophic Cardiomyopathy

Recently, the implantable cardioverter-defibrillator (ICD) has been promoted for prevention of sudden death in hypertrophic cardiomyopathy (HCM). However, the effectiveness and appropriate selection of patients for this therapy is incompletely resolved. To study the relationship between clinical risk profile and incidence and efficacy of ICD intervention in HCM. Multicenter registry study of ICDs implanted between 1986 and 2003 in 506 unrelated patients with HCM. Patients were judged to be at high risk for sudden death; had received ICDs; underwent evaluation at 42 referral and nonreferral institutions in the United States, Europe, and Australia; and had a mean follow-up of 3.7 (SD, 2.8) years. Measured risk factors for sudden death included family history of sudden death, massive left ventricular hypertrophy, nonsustained ventricular tachycardia on Holter monitoring, and unexplained prior syncope. Appropriate ICD intervention terminating ventricular tachycardia or fibrillation. The 506 patients were predominately young (mean age, 42 [SD, 17] years) at implantation, and most (439 [87%]) had no or only mildly limiting symptoms. ICD interventions appropriately terminated ventricular tachycardia/fibrillation in 103 patients (20%). Intervention rates were 10.6% per year for secondary prevention after cardiac arrest (5-year cumulative probability, 39% [SD, 5%]), and 3.6% per year for primary prevention (5-year probability, 17% [SD, 2%]). Time to first appropriate discharge was up to 10 years, with a 27% (SD, 7%) probability 5 years or more after implantation. For primary prevention, 18 of the 51 patients with appropriate ICD interventions (35%) had undergone implantation for only a single risk factor; likelihood of appropriate discharge was similar in patients with 1, 2, or 3 or more risk markers (3.83, 2.65, and 4.82 per 100 person-years, respectively; P = .77). The single sudden death due to an arrhythmia (in the absence of advanced heart failure) resulted from ICD malfunction. ICD complications included inappropriate shocks in 136 patients (27%). In a high-risk HCM cohort, ICD interventions for life-threatening ventricular tachyarrhythmias were frequent and highly effective in restoring normal rhythm. An important proportion of ICD discharges occurred in primary prevention patients who had undergone implantation for a single risk factor. Therefore, a single marker of high risk for sudden death may be sufficient to justify consideration for prophylactic defibrillator implantation in selected patients with HCM.

The innominate vein as alternative access for complicated cardioverter defibrillator revisions

Aims: Venous complications of implantable cardioverter defibrillator (ICD) systems may cause significant problems when the need for system revision or upgrades arises. Such revisions require venous access close to the site of the previous ICD implantation. The internal and external jugular vein have disadvantages due to a long subcutaneous course crossing the clavicle and problems with lead extraction if infection occurs.

Outcome of implantable cardioverter defibrillators in adults with congenital heart disease: a multi-centre study

To investigate outcome and complications of implantable cardioverter defibrillators (ICDs) in adults with congenital heart disease (CHD) and to identify predictors of (in-) appropriate shocks. Sixty-four CHD patients >/= 18 years at first ICD implantation [63% tetralogy of Fallot (TOF) and age at implantation 37 +/- 13 years] were identified using the Dutch adult CHD registry and a Belgian tertiary care centre database. Median follow-up duration was 3.7 years. Early complications included pocket haematoma (n = 3), lead failure (n = 2), and pneumothorax (n = 2). Late complications occurred in 11 (17%) patients, including lead failure (n = 6) and and electrical storm (n = 3). Overall, 30 device-related re-interventions were performed in 20 patients (31%), including four premature generator changes and seven lead replacements. Half of the patients received one or more shocks, and 46 shocks in 15 patients (23%) were classified as appropriate. One hundred and sixty shocks in 26 patients (41%) were classified as inappropriate. No predictors of (in-)appropriate shocks were identified, except TOF being associated with less appropriate shocks than patients with other CHD (HR 0.29, P = 0.02). The ICD provided effective therapy in a quarter of adults with CHD with low complication rates. The incidence of inappropriate shocks, however, appeared to be excessive and warrants further attention.

Inadequate ICD Discharges Due to Diaphragmatic Electromyopotential Oversensing as the First Sign of Right Ventricular Lead Perforation

Right ventricular lead perforation, when acute, is a rare but potentially life-threatening complication of implantable cardioverter defibrillator (ICD) therapy. We report about a patient with early lead perforation presenting with repetitive ICD discharges due to oversensing of diaphragmatic electromyopotentials and describe the management of this complication.

Abstracts for the British Congenital Cardiac Association Annual Meeting: The Barbican, London, 24–25 November 2005: Oral Presentations: Early and midterm outcomes of Implantable Cardioverter Defibrillator (ICD) implantation in patients with repaired Tetralogy of Fallot and pulmonary stenosis – a retrospective review

Introduction: Repair of Tetralogy of Fallot up until recent decades involved aggressive resection and annular enlargement through a right ventriculotomy. This resulted in ventricular scarring and pulmonary incompetence, with an increased risk of ventricular tachyarrhythmia and sudden death in young adulthood. Following the NICE guidelines, implantation of ICDs as primary prevention in patients with repaired Tetralogy is ever increasing. This study aims to determine the rate of appropriate and inappropriate discharges, the success rate of ICD therapy and the impact of ICD implantation on the use of anti-arrhythmic medication in this population of patients. Materials and Methods: This is a retrospective review of patients with repaired Tetralogy of Fallot (n = 18) and pulmonary stenosis (n = 2) with implantable cardioverter defibrillators managed at our tertiary centre. Patients were identified from our outpatient database, their notes and charts were examined and details regarding indication for ICD implantation, device specifications and complications following implantation were collected. Data was also collected on the incidence of appropriate and inappropriate therapies and the success rate of ICD therapy along with the impact of implantation on the usage of anti-arrhythmic medication in these patients. Results: Of the 20 patients, 18 had previous repair of Tetralogy of Fallot and 2 had pulmonary valvotomy and infundibular resection for pulmonary stenosis between 1969 and 1989. 70% (n = 14) of these patients required reoperation with 10 patients having pulmonary valve replacements (PVR), 3 having redo infundibular resections and 1 requiring aortic valve replacement. At the time of consideration for ICD implantation 80% had moderate to severe pulmonary incompetence and 60% had more than mild right ventricular dilatation on echocardiography. Indications for ICD implantation were symptomatic ventricular tachycardia requiring cardioversion (n = 8), ventricular tachycardia on 24 hr tape/Reveal or electrophysiological study (n = 8), ventricular fibrillation (VF)/pulseless ventricular tachycardia (VT) (n = 2) and syncope with an abnormal EPS other than VT (n = 2, high grade ventricular ectopics, sinus node dysfunction).The median age at implantation was 22 years (16.4–43 years). All our patients had dual chamber devices implanted with either dual (n = 13) or single coil (n = 6) ventricular leads. GEM3 AT (n = 5), Marquis DR (n = 8) and Maximo DR (n = 7) generators (Medtronic Inc.) were implanted in sub pectoral position and both anti-tachycardia pacing and cardioversion modes were programmed as part of individualised VT and VF protocols. Early post procedural complications included atrial lead displacement (n = 1) and pneumothorax requiring drainage (n = 1).During a median follow up of 1.6 years (0.03– 4.5 years) several episodes of inappropriate therapies were noted in 6 patients (30%) especially early after implantation. This was found to be mainly due to atrial tachyarrhythmia, double counting of T waves or inaccurate interpretation of varying PR intervals as AV dyssynchrony which were effectively dealt with by changes in device programming. There were 33 episodes of inappropriate anti-tachycardia pacing (ATP) in 4 patients and 19 episodes of inappropriate cardioversion in 5 patients. Appropriate ATP was instituted in 4 patients (25%) with successful termination of all 20 episodes (100% success rate) of ventricular tachycardia. One patient required cardioversion with successful termination of VF. One patient (5%) with troublesome tachyarrhythmia died suddenly of unknown cause, 10 months after AICD implantation having had no detections or therapies on his device.Prior to ICD implantation 8 patients were on amiodarone therapy. At the time of last follow up after AICD implantation all patients were established on anti-arrhythmic agents and of these 6 patients were on amiodarone with the others being effectively managed on beta-blockers and/or flecainide.Late complications of ICD implantation included lead failure in 1 patient requiring replacement 3.3 years after implantation and generator replacement in a patient who was pacemaker dependent a year after implantation due to an advisory issued by the manufacturer regarding the risk of sudden battery depletion. Conclusions: In our study we found a rate of 0.6 appropriate and 1.4 inappropriate therapies (0.9 episodes of inappropriate ATP and 0.5 episodes of inappropriate cardioversion) per patient-year of follow up following ICD implantation which is in keeping with published literature. The mortality in our study group was 5% which is acceptable given the high risk population. Implantation of an ICD allowed switching over from amiodarone to less toxic anti arrhythmic therapy in a proportion of patients. Anti-tachycardia pacing was very successful in terminating tachyarrhythmia in our population with 100% success in terminating ventricular tachycardia.

431 Long term complications of implantable cardioverter defibrillators near or at the time of generator replacement

431 Long term complications of implantable cardioverter defibrillators near or at the time of generator replacement

431 Long term complications of implantable cardioverter defibrillators near or at the time of generator replacement

431 Long term complications of implantable cardioverter defibrillators near or at the time of generator replacement

Patient alert in implantable cardioverter defibrillators: toy or tool?

ObjectivesThe purpose of this study was to analyze the utility of patient-alert features in implantable cardioverter defibrillators (ICDs). BackgroundVarious alert features producing acoustic warning signals have been implemented in newer generation ICDs, but their role in early detection of system-related complications has not been systematically evaluated. MethodsIn 240 patients implanted with Medtronic ICD devices, the following alert features were routinely activated: pacing lead impedance <200 or >2,000 Ω, high-voltage lead impedance <10 or >200 Ω, low battery voltage (elective replacement indicator), long charge time (>18 s), >3 shocks delivered per episode, and all therapies in a zone delivered. Alert events occurring during follow-up were assessed in relation to actual findings (hospital charts, chest X-rays, ICD printouts including sensing/pacing/defibrillation threshold tests, episode data) to determine incidence, sensitivity, and specificity of the alert function. ResultsDuring 12.2 ± 8.9 months, 24 alert events occurred in the 240 patients (pacing lead impedance, n = 4; high-voltage lead impedance, n = 7; low battery voltage, n = 1; >3 shocks, n = 6; all therapies, n = 6). A total of 22 serious complications (necessitating reprogramming or device/lead replacement) were observed, 14 of which were primarily identified through a patient alert (lead fracture, n = 11; connector defect, n = 1; T-wave oversensing, n = 1; battery depletion, n = 1). This reflects a sensitivity of 64% and a specificity of 96% of the alert function for serious complications. With 14 of 24 patient alerts being caused by serious complications, the positive predictive value reached 58%. ConclusionsPatient-alert features are a useful additional tool facilitating early detection of serious ICD complications, but they do not substitute for regular ICD follow-up, because of their low sensitivity.