Transvenous Implantable Cardioverter Defibrillator Implantation Research Articles

Revascularization and Left Ventricular Dysfunction for ICD Eligibility.

Common triggers for sudden cardiac death (SCD) are transient ischemia, hemodynamic fluctuations, neurocardiovascular influences, and environmental factors. SCD occurs rapidly when sinus rhythm degenerates into ventricular tachycardia (VT) and/or ventricular fibrillation (VF), followed by asystole. Such progressive worsening of the cardiac rhythm is in most cases observed in the setting of ischemic heart disease and often associated with advanced left ventricular (LV) impairment. Revascularization prevents negative outcomes including SCD and heart failure (HF) due to LV dysfunction (LVD). The implantable cardioverter-defibrillator (ICD) on top of medical therapy is superior to antiarrhythmic drugs for patients with LVD and VT/VF. The beneficial effects of ICD have been demonstrated in primary prevention of SCD as well. However, yet debated is the temporal management for patients with LVD who are eligible to ICD prior to revascularization, either through percutaneous or surgical approach. Restoration of coronary blood flow has a dramatic impact on adverse LV remodeling, while it requires aggressive long-term antiplatelet therapy, which might increase complication for eventual ICD procedure when percutaneous strategy is pursued; on the other hand, when LV and/or multiorgan dysfunction is present and coronary artery bypass grafting is chosen, the overall risk is augmented, mostly in HF patients. The aims of this review are to describe the pathophysiologic benefits of revascularization, the studies addressing percutaneous, surgical or no revascularization and ICD implantation, as well as emerging defibrillation strategies for patients deemed at transient risk of SCD and/or at higher risk for transvenous ICD implantation.

Temporal trends of device-related infection in de novo transvenous implantable cardioverter-defibrillator Medicare patients with underlying kidney disease.

Kidney disease is a risk factor for device infection in transvenous implantable cardioverter-defibrillator (TV-ICD) implants, with mechanisms that include immunodeficiency and a portal of entry for bacteria that can seed indwelling devices. The purpose of this study was to examine the impact of both kidney disease and dialysis-dependence on the incidence of device-related infection after de novo TV-ICD implantation and how the incidence changes over time in. Medicare 100% administrative and claims data were used to identify patients who underwent de novo TV-ICD implantation between July 1, 2016, and December 31, 2018. Baseline characteristics included underlying kidney disease (none, nondialysis, dialysis) plus device infection during follow-up. Patients were followed for TV-ICD infection up to 78 weeks after implantation. Piecewise Poisson regression was used to predict the incidence of and hazard ratios for infection over time. Overall, 809 of 42,200 patients (1.9%) had at least 1 device infection during mean follow-up of 66 weeks: 484 of 31,217 (1.6%) none; 202 of 9151 (2.2%) nondialysis; and 123 of 1832 (6.7%) dialysis (P <.001 via log-rank test). The incidence of infection increased during the first 8-12 weeks and declined thereafter. Hazard ratios increased over time (dialysis week 12 = 4.9/1000 patient-years; week 52 = 9.8; nondialysis week 12 = 1.4; week 52 = 2.5; all P <.05), as did the difference in cumulative incidence compared with none (dialysis week 12 = Δ11.8 and week 78 = Δ53.5; nondialysis week 12 = Δ1.4 and week 78 = Δ7.0). The incidence of infection after de novo TV-ICD implantation is higher when patients have kidney disease and is substantially higher when patients are dialysis-dependent.

PO-632-04 PATTERNS OF DEVICE-RELATED INFECTION IN DE NOVO TRANSVENOUS IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR MEDICARE PATIENTS WITH UNDERLYING RENAL DISEASE

Renal disease is a risk factor for device infection in transvenous implantable cardioverter-defibrillator (TV-ICD) implants. Since chronic dialysis treatment for advanced renal disease creates a portal of entry for bacteria that can seed indwelling devices, we hypothesized that infection risk could accelerate after TV-ICD implantation in renal patients, especially dialysis dependent (DD) patients. Medicare 100% administrative and claims data were used to identify patients who underwent de novo TV-ICD implantation (7/2016-12/2018). Patients were followed up to 540 days post implantation. Baseline characteristics, including renal disease (none; renal-non-DD; and renal-DD), and device infection during follow-up were identified using claims diagnosis and procedure codes. Statistical analysis consisted of Poisson regression with restricted cubic splines, followed by plotting predicted hazard ratios (HR) for TV-ICD infection in renal-non-DD and renal-DD patients to identify changes in infection risk over time. 42,200 TV-ICD patients were included (9,151 [22%] renal-non-DD; 1,832 [4%] renal-DD), with 809 (2%) device infections. The HRs for infection (Figure) increased with time in both renal disease groups: 2.5-fold in renal-non-DD patients over 18 months; and almost 10-fold in renal-DD patients before leveling off after approximately 12 months. The risk of infection following TV-ICD implantation is significantly higher in patients with underlying renal disease and increases over time, particularly in patients who are dialysis dependent.

Transvenous lead performance of implantable cardioverter-defibrillators and pacemakers.

After the reports of recalled leads, several technological improvements have been introduced and the durability of implantable cardioverter defibrillator (ICD) leads has improved. The incidence of lead failures is now less than in the previous studies. However, there are few reports that have shown the long-term durability of ICD leads as compared to pacemaker (PM) leads. This study analyzed the medium to long-term performance of transvenous ICD leads as compared to PM leads. We retrospectively studied 1227 cases from April 2007 to December 2017 who underwent an initial transvenous ICD or PM implantation. The number of lead failures and patient background characteristics were analyzed. During a median 3-3.5 years follow up period, 1 (0.3%) ICD lead and 18 (2.4%) PM leads failed. The incidence of lead failures was significantly higher in the PM group than ICD group (p=.019). Males were associated with a higher incidence of lead failures in the PM group. Since the era of recalled ICD leads, the durability of ICD leads has remarkably improved and the incidence of lead failures with non-recalled ICD leads has been less than that for PM leads.

P1147Complications in young ICD patients - a retrospective analysis

Abstract Introduction In specific situations implantable cardioverter defibrillator (ICD) therapy is recommended for patients under the age of 40 years. Due to the active lifestyle of this patient population, complication rates in devices with conventional transvenous electrodes may be higher than for the remaining population. Methods The ICD-YOUNG study is a retrospective analysis of consecutive patients ≤ 40 years undergoing transvenous or subcutaneous ICD (s-ICD) implantation, device change or lead revision at our centre between July 2006 and December 2017. Rehospitalization for lead failure or device battery depletion was documented. Results Out of 586 patients undergoing ICD implantation, 35 patients (6.0%) were ≤ 40 years. Mean age was 30.0 ± 7.2 years, 48.6% were female, 37.1% received ICD therapy for primary prevention and 11.4% primarily received s-ICD. Median follow up was 7.3 (interquartile range, 1.8-12.0) years, with a lower follow up duration in s-ICD patients than conventional ICD patients (median, 2.9 vs. 9.0 years). Over the course of follow-up, 37.1% received successful anti-tachycardia therapy. 19.4% of patients in the conventional ICD group had right ventricular lead problems requiring intervention, while none of the s-ICD patients had to be revised. Time to first device change due to battery depletion and/or device upgrade was similar in young and remaining patients (median 5.4 vs 6.0 years, p = 0.23). Discussion Young patients requiring ICD have a high rate of lead problems. In most young patients, s-ICD therapy is an encouraging alternative to conventional ICD therapy with a lower lead failure rate.

Defibrillation threshold testing during implantable cardioverter defibrillator implantation: 5-year follow-up.

Defibrillation threshold (DFT) testing is a routine practice in some Asian countries for patients receiving an implantable cardioverter defibrillator (ICD). However, there are few long-term data about the necessity of intraoperative DFT testing in an Asian population. We investigated the safety of DFT testing and the long-term clinical outcomes in Asian patients undergoing ICD implantation. All patients undergoing de novo transvenous ICD implantation were randomized to undergo periprocedural DFT testing. The study included 67 patients (50 males; 51.5 ± 16.9years) who underwent ICD implantation with (n = 33) or without (n = 34) intraoperative DFT testing between March 2012 and February 2014. We compared first-shock success, composite safety end points (the sum of complications recorded at 30days), arrhythmic death, and all-cause mortality. The baseline clinical characteristics and the procedural-related adverse event rate (3.0% with DFT vs. 0% with non-DFT, p = 0.214) did not differ between groups. The programmed output of the first shock was lower in the DFT testing group (22.9 ± 4.4J vs. 25.3 ± 5.4J, p =0.007). However, there were no significant differences between groups for all-cause mortality (12.1% vs. 17.6%, p = 0.526) or first-shock success rate for ventricular arrhythmia (100% vs. 88.2%, p = 0.471). There were no between-group differences in periprocedural safety, complications, and long-term clinical outcomes. Our results suggest that DFT testing in Asian patients allows reduction of the programmed output of the first shock, but does not affect long-term clinical outcomes.

Peri-procedural routines, implantation techniques, and procedure-related complications in patients undergoing implantation of subcutaneous or transvenous automatic cardioverter-defibrillators: results of the European Snapshot Survey on S-ICD Implantation (ESSS-SICDI).

The aim of this European Heart Rhythm Association (EHRA) prospective snapshot survey is to assess peri-procedural practices, implantation techniques, and short-term procedure-related complications associated with implantation of subcutaneous implantable cardioverter-defibrillator (S-ICD) or transvenous implantable cardioverter-defibrillator (TV-ICD), across tertiary European electrophysiology centres. An internet-based electronic questionnaire concerning implantation settings, peri-procedural routines, techniques, personnel, complications, and patient outcomes was sent to the centres routinely implanting both TV-ICDs and S-ICDs. The centres were requested to prospectively include consecutive patients implanted with either TV-ICD or S-ICD during the 8-week enrolment period. Overall, 20 centres from 6 countries enrolled 429 consecutive patients. Subcutaneous implantable cardioverter-defibrillators (20%) compared with TV-ICD were implanted mainly under general anaesthesia (72% vs. 14%), in the surgical operation room settings (69% vs. 43%), with more frequent prophylactic antibiotic administration (82% vs. 91%), and post-implant defibrillation testing (85% vs. 7%, all P < 0.05). Feasibility (implantation duration of 45 min) and short-term complication rates (4%) were comparable for S-ICDs and TV-ICDs, but the spectrum of complications varied, despite different baseline characteristics of patients undergoing the S-ICD vs. TV-ICD implantation. This EHRA snapshot survey provides important insights into the implantable cardioverter-defibrillator implantation routines and patient outcomes. Our study showed differences between the S-ICD and TV-ICD implantation routines with respect to implantation settings, peri-procedural management, and pre-defined procedural endpoints. However, the comparable duration of S-ICD or TV-ICD implantation and similar rates of peri-procedural complications indicate that both devices can be routinely used in clinical practice.

The Subcutaneous Implantable Cardioverter-Defibrillator: A Practical Review and Real-World Use and Application

The subcutaneous implantable cardioverter-defibrillator (ICD) is a novel technology using a subcutaneous (extrathoracic) system for treatment of potential lethal ventricular arrhythmias. It avoids many of the risks of transvenous ICD implantation. It may be considered in patients having an ICD indication who do not have a pacing and/or cardiac resynchronization therapy indication, and who are unlikely to benefit from antitachycardia pacing therapy. We review patient selection, system components, the implantation technique, and screening considerations for subcutaneous ICD implantation. Its uses in specific patient populations, including children, patients with congenital heart disease, hypertrophic cardiomyopathy, or end-stage renal disease, and patients with preexisting pacemakers, are highlighted. Areas of future investigation are reviewed, including potential use with leadless pacing and magnetic resonance imaging.

ICD implantation without intraoperative testing does not increase the rate of system modifications and does not impair defibrillation efficacy tested in follow-up

The need for implantable cardioverter-defibrillator (ICD) defibrillation testing (DT) and subsequent intraoperative system modifications is discussed controversially. The study's goal was to prove that consequent abdication of intraoperative DT does not impair defibrillation efficacy and does not increase the rate of postoperative system revisions. In a prospective single-center observational study, 609 out of 648 consecutive patients underwent transvenous ICD implantation (left-sided, active can, dual coil lead, and biphasic shock waveform) waiving intraoperative DT. Defibrillation efficacy was validated prior to hospital discharge (PHD) by applying two 10J safety margin (SM) shocks. Following "schockless" implantation 580 out of 609 patients (95.2 %) met a 10J SM with default programming. Shock path reversal provided 10J SM in 13 out of 29 cases with initially failed DT. In four patients (0.7 %) maximum energy shocks were ineffective. There was no morbidity or mortality related to DT. The total rate of surgical ICD revisions was 1.8 %. Routine ICD implantation without intraoperative DT does not lead to an increased rate of postoperative system modifications and does not decrease defibrillation efficacy as tested PHD.

Complications of ICD Generator Change and Implantations

Although implantable cardioverter-defibrillator (ICD) therapy can be lifesaving, complications are a possibility with implantation and during longterm follow-up. Though early ICDs, placed via open thoracotomy, were associated with a significant risk, the modern era of transvenous ICD implantation has reduced the surgical risk substantially. The conclusion of several decades of randomized clinical trials supporting the use of ICDs and cardiac resynchronization therapy (CRT) in patients with moderate-to-advanced heart failure highlights an important paradox. Whereas nonthoracotomy ICD implantation can be performedwith fewercomplications thanearlydevices, the patients now considered for this therapy are generally more ill and often with advanced heart failure. The impact of significant cardiac disease and associated comorbid medical illness on complication rates must also be considered. This article reviews the available data reporting complications associated with ICD procedures. Adverse events associated with both the acute procedural risk as well as those events that occur later are examined.

An alternative technique of implanting a nontransvenous implantable cardioverter-defibrillator system in adults with no or limited venous access to the heart

In some patients at high risk for sudden cardiac death, a transvenous implantable cardioverter-defibrillator (ICD) cannot be implanted owing to limited vascular access. These patients can benefit from a nontransvenous defibrillation system consisting of a rate-sensing lead attached to the epicardium and a subcutaneous (SQ) array. We examine the feasibility, safety, and clinical circumstances requiring implant of nontransvenous defibrillation system in adults. Eight patients received an ICD system composed of an SQ array and either a chronic endocardial rate/sense lead (n = 5) or a new epicardial rate/sense lead (n = 3) for primary (n = 2) or secondary (n = 6) prevention. The obstacles to transvenous ICD implantation included recurrent endovascular lead infections (n = 1), congenital heart disease (n = 4), and superior vena cava occlusion (n = 3). The array was tunneled posteriorly, and the epicardial rate-sensing leads were implanted by left lateral minithoractomy. Four patients also required left ventricular pacing. Successful defibrillation was obtained in all patients at 29 ± 2.6 J. There were no major cardiovascular complications. Over a mean follow-up of 545 ± 204 days there was one appropriate and no inappropriate shocks. None of the patients required system revision. There were no significant changes in impedance, pacing threshold, or ventricular sensing observed with the epicardial leads and no change in high-voltage impedance. The nontransvenous defibrillation system described is an effective technique in an adult population with acceptable pacing and defibrillation threshold.

Effect of Transvenous Cardiac Resynchronization Therapy Device Implantation on Cardiac Troponin I Release

Pacemaker and implantable cardioverter defibrillator (ICD) implantation increases cardiac troponin I (cTnI) levels which indicates myocardial injury. During implantation of a cardiac resynchronization therapy (CRT) device, balloon inflation for coronary sinus (CS) venogram, cannulation of CS side branch, and electrode advancement may interfere with CS drainage and, hence, may decrease the washout of toxic metabolites from the heart. Thus, CRT implantation may further increase cTnI levels. In this study, we investigated the effects of CRT implantation on cTnI release. We included 10 patients (mean age = 57 +/- 15 years) in whom a successful transvenous CRT system was implanted (CRT group). Twenty patients (mean age = 65 +/- 10 years) who underwent a transvenous pacemaker or ICD implantation were included as the control group. Blood samples for cTnI were drawn at baseline and at six, 12, 18, and 24 hours thereafter. Baseline median cTnI levels were similar in CRT and control groups (0.03 ng/mL vs 0.02 ng/mL, respectively; P = 0.1). Postoperative cTnI levels during 24 hours were significantly higher in the CRT group (P < 0.05) by two-way repeated measures of analysis of variance. Post hoc analysis revealed that cTnI levels were higher at the 6th, 12th, 18th, and 24th hours compared to baseline levels (P < 0.001, P < 0.001, P < 0.01, and P < 0.01, respectively). There was a significant difference in the area under the curves (AUCs) of cTnI measurements (1.79 hr.ng/mL in the CRT group and 0.78 hr.ng/mL in the control group, P < 0.05). Postoperative cTnI levels were higher after CRT implantation than simple pacemaker/ICD implantation. This may be due to CS manipulation during CRT implantation.

Appropriate ICD Therapy in Patients With Idiopathic Dilated Cardiomyopathy Long-Term Follow-Up

The implantable cardioverter defibrillator (ICD) has proved effective in preventing sudden death and decreasing mortality in randomised secondary prevention trials. Some nonrandomized studies have reported different incidences and predictors of appropriate ICD therapy in patients with idiopathic dilated cardiomyopathy (DCM). The antiarrhythmic and other medical therapies were different between the published studies and it was reported that not using beta-blockers was a predictor of appropriate ICD therapy. In the present study, we report on our long-term experience with ICD therapy in patients with DCM, the majority of whom were treated with beta-blockers and amiodarone. The study population consisted of 25 patients with DCM who underwent initial transvenous ICD implantation between December 1995 and May 2005. Indications for ICD implantation were monomorphic sustained ventricular tachycardia (VT) in 16 patients (64%), cardiac arrest in 8 patients (32%), and syncope plus inducible VT in one patient. Twenty-four patients underwent an electrophysiologic study (EPS). In 18 patients, the ICDs were programmed to only shocks and in 7 patients an additional antitachycardia pacing program was performed. One patient was lost to follow-up and 24 patients were followed-up primarily in our ICD pacemaker outpatient clinic. Appropriate ICD therapy was defined as antitachycardia pacing therapy or shock for tachyarrhythmia determined by evaluation of the clinical information and by device diagnostics to be either ventricular fibrillation or ventricular tachycardia. The mean follow-up was 39.29 +/- 30.59 months after ICD implantation. At follow-up, 17 patients were using a beta-blocker and 16 patients amiodarone. Appropriate ICD therapy was observed in 14 patients (58%). The detected arrhythmias were VT in 12 patients, ventricular fibrillation (VF) in one, and VT and VF in one patient. The time to first ICD therapy was 15.93 +/- 18.45 (range, 1-74) months. Using the Kaplan-Meier method, the percent survival free of appropriate ICD therapy was 82%, 72%, 66%, and 55% at 1, 2, 3, and 4 years follow-up, respectively. The clinical, echocardiographic, and electrophysiologic characteristics did not differ between those who did and did not receive appropriate ICD therapy. However, the mean QRS duration was significantly longer in patients who received appropriate ICD therapies. Cox regression analysis did not reveal any factors that predicted appropriate ICD therapy. Five patients (21%) died during follow-up. Four deaths were classified as cardiac and one as noncardiac. The cumulative survival from total death was 94%, 82%, 82%, and 69%, and the cumulative survival from cardiac death was 94%, 82%, 82%, and 76% during 1, 2, 3, and 4 years of follow-up, respectively. In summary, in this selected patient population with DCM, the majority of patients were unresponsive to beta-blocker and antiarrhythmic therapy. Most of these patients received appropriate ICD therapy during follow-up. Cox regression analysis did not identify any factors that predicted appropriate ICD therapy. Additional trials with larger patient populations are needed to detect the predictors of appropriate ICD therapy in patients with DCM.

Indications for implantable cardioverter defibrillator therapy.

The implantable cardioverter defibrillator (ICD) is now an integral therapy for cardiac patient care. More than 20 years have passed since the first ICD implant. Sudden cardiac death from arrhythmia (ventricular tachycardia and fibrillation) has been significantly decreased because of the use of ICD therapy. Primary treatment trials have shown ICD therapy to be superior to drug therapy. Most of these trials compared ICD therapy with amiodarone or sotalol. Prevention trials have also been completed. Patients with nonsustained ventricular tachycardia, low left ventricular ejection fraction, and coronary artery disease were evaluated with electrophysiology studies. Patients with inducible ventricular arrhythmias were treated with ICD or drug suppression therapy. ICD therapy was superior to drug therapy for prevention of fatal arrhythmias. Ongoing trials include evaluation of ICD therapy for patients with high-risk substrates: congestive heart failure, dilated cardiomyopathy, hypertrophic cardiomyopathy, and repolarization syndromes. Factors such as medication inefficacy/side effects, transvenous ICD implantation and overwhelming mortality benefits have expanded ICD usage beyond the original restrictive guidelines.

Detection of myocardial injury during transvenous implantation of automatic cardioverter-defibrillators

OBJECTIVESThe present study was designed to assess the extent of myocardial injury in patients undergoing transvenous implantation of an automatic implantable cardioverter-defibrillator (ICD) using cardiac troponin I (cTNI), which is a highly specific marker of structural cardiac injury.BACKGROUNDDuring ICD implantation, repetitive induction and termination of ventricular fibrillation (VF) via endocardial direct current shocks is required to demonstrate the correct function of the device. Transthoracic electrical shocks can cause myocardial cell injury.METHODSMeasurements of total creatine kinase (CK), CK-MB, myoglobin, cardiac troponin T (cTNT) and cTNI were obtained before and after ICD implantation in 49 consecutive patients. Blood samples were drawn before and 2, 4, 8, and 24 h after implantation.RESULTSElevations of CK, CK-MB, myoglobin, cTNT and cTNI above cut-off level were found in 25%, 6%, 76%, 37% and 14% of patients, respectively, with peak cTNI concentrations ranging from 1.7 to 5.5 ng/ml. Cumulative defibrillation energy (DFE), mean DFE, cumulative VF time, number of shocks as well as prior myocardial infarction (MI) were found to be significantly related to a rise of cTNI. Mean DFE ≥ 18 J and a recent MI were identified as strong risk factors for cTNI rise.CONCLUSIONSDuring transvenous ICD implantation myocardial injury as assessed by cTNI rise occurs in about 14% of the patients. Peak cTNI concentrations are only minimally elevated reflecting subtle myocardial cell damage. Patients with a recent MI and a mean DFE ≥ 18 J seem to be prone to cTNI rise.

Age dependent efficacy of implantable cardioverter-defibrillator treatment: observations in 450 patients over an 11 year period

ObjectiveTo determine whether implantable cardioverter-defibrillator (ICD) treatment is beneficial in elderly patients with life threatening ventricular tachyarrhythmias.DesignSince January 1984, ICDs were implanted in 450 patients to evaluate surgical risk, complications...

The “Modern” Implantable Cardioverter-Defribrillator: Comparing It to Those of the Late 1980s

To determine whether implantable cardioverter-defibrillator (ICD) therapy is influenced by new technological advances, we studied the follow-up of 480 patients who underwent ICD implantation between January 1984 and March 1996. In these patients surgical risk, complications, and mean survival was evaluated in relation to the time of ICD implant: 124 patients (26%) underwent ICD implantation during 1984–1989 (group 1) and 356 patients (74%) during 1990–1996 (group 2). Epicardial lead systems were implanted in 209 patients (44%), whereas transvenous lead systems were implanted in 271 patients (56%). Perioperatively, 13 patients (3%) died, significantly more frequently after epicardial (12 of 209 patients, 5%) than after transvenous (1 of 271 patients, <1%) ICD implantation (p < 0.05). During a mean follow-up of 28 ± 26 months (range < 1 to 129 months), 97 patients (20%) died. Of these, 9 patients (2%) died from sudden arrhythmic death; 7 patients (1%) died suddenly, probably as a result of nonarrhythmic causes; 60 (13%) died from other cardiac causes (congestive heart failure, myocardial infarction); and 21 (4%) died from noncardiac causes. The 3-, 5-, and 6-year survival for arrhythmic mortality was 90% and 89% in patients who underwent ICD implantation during 1984–1989 as compared with a 3-, 5-, and 6-year survival rate of 97% in patients with ICD implant since 1990 (p <0.05). In addition, the 3-, 5-, and 6-year total mortality was significantly better in group 2 (81%, 67%, 67%) than in group 1 (70%, 61%, 54%) (p <0.05). A total of 362 (75%) received ICD discharges (mean incidence 21 ± 43 shocks per patient), with a similar incidence among both patient groups (group 1: 78%; group 2: 74%; p = nonsignificant). The mean interval between ICD implant and the first ICD therapy was similar between both groups with a mean interval of 11 ± 13 months (group 1: 11 ± 13 months, group 2: 9 ± 6 months; p = nonsignificant). Our data demonstrate that patients who underwent ICD implantation since 1990 clearly benefit from technical advances (nonthoracotomy ICDs, biphasic shocks, antitachycardia pacing). (Am J Cardiol 1996;78(suppl 5A):3–8)

Predictors of outcome in patients with implantable transvenous cardioverter defibrillators

The identification of patients who benefit most from implantable cardioverter defibrillator (ICD) therapy is of great interest. To find out if clinical variables, the signal-averaged electrocardiogram, and electrophysiologic study predict occurrence of appropriate ICD discharges and death, we followed-up on 76 patients after implantation of a transvenous ICD. During a mean follow-up period of 18.2 ± 6.4 months, 29 patients (38.6%) experienced at least one appropriate episode. When these patients were compared with those who had either no therapy or inappropriate episodes, three variables were found to be significant in the identification of patients who experienced appropriate discharges: (1) The mean ejection fraction of patients who received appropriate discharges was 35.4% ± 13.5% versus 45.1% ± 15.3% in the other group ( p < 0.05); (2) patients with appropriate therapy had sustained monomorphic ventricular tachycardia that was more likely to be inducible (75.9% vs 21.2%, p < 0.01); and (3) in patients with appropriate therapy ventricular fibrillation was less likely to be inducible (10.3% vs 25.5%, p < 0.05). The signal-averaged electrocardiograms were more often abnormal, but the differences were not significant. The total mortality rate in our patient group was 7.8%, with nonsudden cardiac death in four patients, noncardiac death in one patient, and sudden death in one patient. In our patient group a lower ejection fraction and inducible sustained monomorphic ventricular tachycardia were predictors of future ICD discharge after implantation. The survival rate after transvenous ICD implantation is excellent; a longer follow-up period is necessary to further define predictors of total mortality rate.

Infection of implantable cardioverter defibrillator systems: a preventable complication?

In a consecutive series of 164 patients undergoing primary implantation of an implantable cardioverter defibrillator (ICD), two patients died in the hospital (1.2%) and early system infection developed in one patient requiring explantation of the device (0.61%). Late infection developed in one additional patient (0.61%) 7 months after transvenous ICD implantation, and was thought to be due to a recent intravascular catheterization. Symptomatic generator pocket hematomas developed in three patients, two of which were treated by simple evacuation and one with temporary generator explanation and subsequent reimplantation of the unit in a new pocket. No infection developed in these three patients during follow-up. Generator erosion without obvious system infection developed in a fourth patient. Guidelines for the prevention of infection in ICD systems are presented.