Clinical variables predicting inappropriate use of implantable cardioverter-defibrillator in patients with coronary heart disease or nonischemic dilated cardiomyopathy

Effect of Novel Programming on Inappropriate Implantable Cardioverter-Defibrillator Therapy in Patients With Very Low Ejection Fraction (from A MADIT-RIT)

The Multicenter Automatic Defibrillator Implantation Trial - Reduce Inappropriate Therapy showed a significant reduction in the risk of inappropriate therapy in patients with a programmed high-rate cutoff ≥200 beats per minute or delayed therapy for events ≥170 beats per minute compared with conventional programming. We aimed to characterize outcomes by left ventricular ejection fraction (LVEF) ranges for patients with high-rate, delayed, or conventional implantable cardioverter-defibrillator programming. We assessed the effect of LVEF (LVEF <15%, LVEF 15% to 25%, LVEF >25%) on the risk of inappropriate conventional implantable cardioverter-defibrillator therapy and death in Multicenter Automatic Defibrillator Implantation Trial - Reduce Inappropriate Therapy. Inappropriate therapies and death were independently evaluated by the adjudication committee. Statistical methods involved Kaplan-Meier time-to-event graphs and Cox proportional hazards regression analyses. The study involved 140 patients (9%) with LVEF 15%, 585 with LVEF 15% to 25% (39%), and 774 with LVEF >25% (52%). High-rate or delayed programming significantly reduced the risk of inappropriate therapy compared with conventional programming in patients with all LVEFs (p <0.001 for all LVEF). Patients with LVEF <15% had an exceptional 97% lower risk of inappropriate therapy, with high-rate programming than conventional programming (hazard ratio 0.028, p = 0.001), without an increase in mortality. High-rate and delayed programming is superior to conventional programming in all LVEF ranges, without adverse effects.

Frequency, predictors and prognostic impact of implantable cardioverter defibrillator shocks in a primary prevention population with heart failure and reduced ejection fraction

AIMS

The role of the implantable cardioverter defibrillator (ICD) in primary prevention real-world population is debated. We sought to evaluate the incidence, predictors and prognostic impact of ICD shocks in consecutive heart failure patients implanted for primary prevention at our tertiary institution.

METHODS AND RESULTS

We retrospectively selected a sample of 497 patients (mean age 64.8 years, 82.1% men, average left ventricular ejection fraction, LVEF, 27.1%). At long-term follow-up (median time 70.4 months), total mortality was 40.8%, and 16.5% of patients had received at least one appropriate shock (3.12%/year). Inappropriate shock [odds ratio (OR) 1.93, 95% confidence interval (95% CI) 1.08-3.47; P = 0.027] and length of follow-up (1 year, OR 1.01, 95% CI 1.00-1.01; P = 0.0031) were associated with the occurrence of appropriate shock, whereas atrial fibrillation (OR 2.65, 95% CI 1.55-4.51, P < 0.001), length of follow-up (1-year OR 1.01, 95% CI 1.00-1.01, P < 0.001) and appropriate shock (OR 1.93, 95% CI 1.08-3.47, P = 0.027) were associated with the occurrence of inappropriate shock. Neither appropriate nor inappropriate shock independently increased mortality risk, whereas older age (hazard ratio 1.05; 95% CI 1.04-1.07; P < 0.001), atrial fibrillation (hazard ratio 2.25; 95% CI 1.67-3.02; P < 0.001) and lower LVEF (hazard ratio 0.97; 95% CI 0.94-0.99; P = 0.004) did.

CONCLUSION

Incidence of shocks in real-world primary prevention ICD recipients might be lower than expected, and the association between ICD shocks and prolongation of survival is not as clear-cut as might be perceived. Further investigations from larger real-world samples are warranted.

The role and outcomes of new supraventricular tachycardia among patients with mild heart failure

INTRODUCTION

We aimed to assess the predictors of new supraventricular tachycardia (SVT) and the association of new SVT with subsequent clinical outcomes among mild heart failure (HF) patients.

METHODS AND RESULTS

The study population comprised patients enrolled in MADIT-CRT, after exclusion of patients with atrial arrhythmias before enrollment (N = 325). Multivariate analysis was used to identify predictors of new-onset SVT and the association of time-dependent development of SVT with subsequent ventricular tachyarrhythmic events (VTEs), HF-hospitalizations, and death. SVT burden was categorized into three groups based on the number of episodes per patient; (a) Low <10, (b) Intermediate ≥10 but <20, and (c) High ≥20. During mean follow up of 3.4 ± 1.1 years, 41(3%) subjects developed new SVT. African American race, diastolic blood pressure (DBP) >80 mmHg and prior non sustained ventricular arrhythmia were independent predictors for SVT. Multivariate analysis showed that the development of time-dependent SVT was associated with a >4-fold increased risk for VTEs (HR = 4.3; 95% CI: 1.6-11.7; P = .004) and with a >6-fold increased risk for all-cause mortality (HR = 6.5; 95% CI: 2.3-18.7; P < .001), but not with HF hospitalizations (HR = 2.2; 95% CI: 0.7-7.2; P = .17). Intermediate, and high SVT-burden were each independent risk factors for death when compared with Low burden (HR = 9.1; P = .03, and HR = 19.4; P < .001; respectively).

CONCLUSIONS

In patients with mild HF, the development of new-onset SVT after device implantation is related to distinct baseline clinical and epidemiologic characteristics and is associated with a significant increase in subsequent adverse outcomes, including VTEs and death.

Predictors and outcomes of atrial tachyarrhythmia among patients with implantable defibrillators

BACKGROUND

Atrial tachyarrhythmias (ATAs) are common among heart failure (HF) patients.

OBJECTIVE

The purpose of this study was to assess predictors for the development of new ATA and its components (atrial fibrillation/flutter [AF], supraventricular tachycardia [SVT]), and their association with subsequent clinical outcomes.

METHODS

We assessed predictors for first and recurrent ATA, AF, and SVT among 1500 patients in MADIT-RIT (Multicenter Automatic Defibrillator Implantation Trial-Reduce Inappropriate Therapy). We also investigated the association of new ATA, AF, or SVT with subsequent ventricular arrhythmia (VA), adverse events (HF hospitalization, syncope, or death), or death by time-dependent analysis.

RESULTS

During 17 months of follow-up, 286 patients (19%) developed new ATA, of whom 92 (6%) had AF and 194 (12%) had SVT. Younger age (≤65 years), diastolic blood pressure ≥72 mm Hg, heart rate ≥63 bpm, absence of diabetes, and prior atrial arrhythmia were independent predictors of ATA. Prior atrial arrhythmia was the only predictor of AF (hazard ratio 3.14; P <.001). New ATA was associated with significantly increased risk for subsequent VA (HR 2.12; P <.001), increased adverse events (HR 1.42; P <.001), and death (HR 1.85; P = .038). New AF and new SVT were both independently associated with >2-fold increased risk for the development of subsequent VA (HR 2.21; P = .012l and HR 2.15; P <.001, respectively) and adverse events.

CONCLUSION

Among MADIT-RIT patients, younger age, absence of diabetes, higher blood pressure, higher heart rate, and prior atrial arrhythmia predicted device-detected ATA. Both AF and SVT were associated with increased risk for subsequent VA and adverse events. Aggressive management should be considered in HF patients who develop new-onset, device-detected ATA to improve clinical outcomes.

Long-term incidence of inappropriate shocks in patients with implantable cardioverter defibrillators in clinical practice-an underestimated complication?

BACKGROUND

Implantable cardioverter defibrillators (ICD) are life-saving device therapy, and patients often carry devices for decades with interim pulse generator exchanges. Inappropriate shocks are associated with impaired quality of life and increased mortality, but available data on their incidence and etiology outside of clinical trials is limited and usually restricted to the lifespan of a singular device. We hypothesized that the incidence in clinical practice is underestimated and aimed this study to retrospectively assess the long-term incidence and etiology of inappropriate shocks in a real-world cohort of patients with multiple ICDs over a long follow-up period.

METHODS

Patients with ICDs implanted between 1998 and 2012 in two Swiss cardiology departments and at least one device exchange in the same department thereafter were included in this cohort. Retrospective analysis with follow-up until 2016 was conducted to assess incidence and etiology of inappropriate ICD shocks.

RESULTS

Two hundred forty-nine ICDs were implanted in 100 patients (mean age: 60.1 ± 11.7; 80% male). Over a mean follow-up time of 11.2 (± 3.6) years, 555 shocks occurred in 55 patients. One hundred twenty-three (22%) shocks in 23 (23%) patients were inappropriate. Supraventricular arrhythmia and oversensing were the most frequent causes of inappropriate shock. Patients with younger age or previous supraventricular arrhythmias were at increased risk of inappropriate shocks. Patients with inappropriate shocks during the lifespan of their first ICD were at increased risk for inappropriate shocks in subsequent devices.

CONCLUSIONS

Inappropriate shocks are an underestimated and frequent problem in clinical practice with an incidence that may exceed numbers of previously reported clinical trials with shorter follow-up periods. Patients at increased risk for inappropriate shocks need careful evaluation of potential therapeutic optimization strategies including pharmacological treatment, device programming, electrophysiological ablation, device downgrading, and telemonitoring.

Low rate of and rapid attention to inappropriate ICD shocks with remote device and rhythm monitoring: a qualitative study

Objectives

Inappropriate shocks are unpleasant and painful. We hypothesise that remote monitoring and careful attention to known and incident atrial fibrillation (AF) can reduce inappropriate shocks to a very low level in clinical praxis.

Methods

Altogether 259 patients with implantable cardioverter defibrillator implanted for secondary (S, n=113) and primary (P, n=146) prevention were followed via remote monitoring. At implant, 42S (37%) and 54P (37%) patients had known AF.

Results

Inappropriate shocks, all but five due to AF, occurred in 7S (6.2%) and 11P (7.5%), and there were only inappropriate shocks in 5/7S and in 8/11P. They occurred in four of 42S (9.5%) with and in three of 71S (4.2%) without known AF, and in seven of 54P (13%) with and in four of 92P (4.3%) without known AF. The median time from shock to action was 5 and 1 day, respectively. Actions were medication with amiodarone, β blockers, β blockers+amiodarone or β blockers+digoxin (n=5), β blockers+insertion of an atrial lead (n=1), replacement of a fractured lead (n=2), reprogramming in combination with β blockers, digoxin or amiodarone (n=4), reprogramming (n=2) and none (n=4). After action, four further inappropriate shocks occurred during more than 2 years of follow-up, all due to AF.

Conclusions

Inappropriate shocks occurred at a low rate and most often because of AF known at implant. Remote monitoring enabled rapid action, after which few inappropriate shocks occurred over more than 2 years. Attention to known and incident AF was the most important action to reduce inappropriate shocks.

Predictors and Proarrhythmic Consequences of Inappropriate Implantable Cardioverter-Defibrillator Therapy

BACKGROUND

Despite the benefits of implantable cardioverter-defibrillator (ICD) therapy, inappropriate shocks can lead to multiple adverse effects. The aim of this study was to clarify the predictors of inappropriate ICD shocks and their proarrhythmic consequences.

METHODS AND RESULTS

We retrospectively studied 316 consecutive patients who underwent ICD implantation from December 2000 to December 2011. Of them, 70 (22%) experienced inappropriate ICD shocks without proarrhythmia requiring some intervention; 2 patients (0.6%) had proarrhythmic inappropriate ICD therapy by antitachycardia pacing (ATP), thereby calculated to be 0.18% of patients per year. However, they did not have syncope from this inappropriate ATP. Multivariate analysis identified younger age (≤56 years: hazard ratio [HR] 1.68, 95% confidence interval [CI] 1.02-2.77, P=0.043), paroxysmal atrial fibrillation (HR 3.00, 95% CI 1.64-5.31, P=0.0002), stroke (HR 2.23, 95% CI 1.11-4.47, P=0.024), and no diuretic use (HR 1.72, 95% CI 1.03-2.93, P=0.039) as independent predictors of the occurrence of inappropriate ICD shocks.

CONCLUSIONS

Young age, paroxysmal atrial fibrillation, stroke, and no use of diuretics were independently associated with inappropriate ICD shocks. Proarrhythmic inappropriate ICD therapy was observed with an annual incidence of 0.18% by ATP.

Analyses of inappropriate shocks in a Spanish ICD primary prevention population: Predictors and prognoses

BACKGROUND

ICDs have been demonstrated to be highly effective in the primary prevention of sudden death, but inappropriate shocks (IS) occur frequently and represent one of the most important adverse effects of ICDs. The aim of this study was to analyze IS and identify the clinical predictors and prognostic implications of ISs in a real-world primary prevention ICD population.

METHODS

This multicenter retrospective study was performed in 13 centers with experience in the field of ICD implantation (at least 30 per year) and ICD follow-up in Spain. All consecutive patients who underwent ICD implantation for primary prevention between January 2008 and May 2014 were included.

RESULTS

One-thousand-sixteen patients were included, and 4 (0.39%) were lost to follow-up. Two-hundred-seventeen (21.4%) patients suffered from shock; 69 (6.8%) of these patients experienced IS, and 154 (15.4%) experienced appropriate shocks (AS). Age (<65 years, hazard ratio (HR) 2.588 [95% CI 1.282-5.225]; p=0.008), history of atrial fibrillation (HR 2.252 [95% CI 1.230-4.115]; p=0.009), non-ischemic myocardiopathy (HR 2.258 [95% CI 1.090-4.479]; p=0.028), and cardiac resynchronization therapy (HR 0.385 [95% CI 0.200-0.740]; p=0.004) were identified as IS predictors in a multivariate analysis. IS was not associated with rehospitalization due to heart failure, myocardial infarction, cardiovascular mortality or all-cause mortality.

CONCLUSIONS

This analysis of our national registry identified the independent IS predictors of age, atrial fibrillation history and cardiac resynchronization therapy and suggests that ISs are not linked to poorer clinical endpoints.

Atrial fibrillation in cardiac resynchronization therapy with a defibrillator: a risk factor for mortality, appropriate and inappropriate shocks

INTRODUCTION

Knowledge about predictive factors for mortality and (in)appropriate shocks in cardiac resynchronization therapy with a defibrillator (CRT-D) should be available and updated to predict clinical outcome.

METHODS

We retrospectively analyzed 543 consecutive patients assigned to CRT-D in 2 tertiary medical centers. The aim of this study was to assess risk factors for all-cause mortality, appropriate and inappropriate shocks.

RESULTS

Mean follow-up time was 3.2 (±1.8) years. A total of 110 (20%) patients died, 71 (13%) received ≥1 appropriate shocks, and 33 (6.1%) received ≥1 inappropriate shocks. No patients received a His bundle ablation and biventricular pacing percentage was not analyzed. Multivariable Cox regression analysis showed that a history of atrial fibrillation (AF) (HR 1.74 CI 1.06-2.86), higher creatinine (HR 1.12; CI 1.08-1.16), and a poorer left ventricular ejection fraction (LVEF) (HR 0.97; CI 0.94-1.01) independently predict all-cause mortality. In the entire cohort, history of AF and secondary prevention were independent predictors of appropriate shocks and variables associated with inappropriate shocks were history of AF and QRS ≥150 milliseconds. In primary prevention patients, history of AF also predicted appropriate shocks as did ischemic cardiomyopathy and poorer LVEF. History of AF, QRS ≥150 milliseconds, and lower creatinine were associated with inappropriate shocks in this subgroup. Appropriate shocks increased mortality risk, but inappropriate shocks did not.

CONCLUSION

In symptomatic CHF patients treated with CRT-D, history of AF is an independent risk factor not only for mortality, but also for appropriate and inappropriate shocks. Further efforts in AF management may optimize the care in CRT-D patients.

Multicenter automatic defibrillator implantation trial: reduce inappropriate therapy (MADIT-RIT): background, rationale, and clinical protocol

The implantable cardioverter defibrillator (ICD) is highly effective in reducing mortality due to cardiac arrhythmias in high-risk cardiac patients. However, inappropriate therapies caused predominantly by supraventricular tachyarrhythmias (SVTs) remain a significant side effect of ICD therapy despite medical treatment, affecting 8-40% of patients. The MADIT-RIT is a global, prospective, randomized, nonblinded, three-arm, multicenter clinical investigation to be performed in the Unites States, Europe, Canada, Israel and Japan, and will utilize approximately 90 centers with plan to enroll 1500 patients programmed to three treatment arms. The objective of the MADIT-RIT trial is to determine if dual-chamber ICD or CRT-D devices with high rate cutoff (MADIT-RIT-Arm B) and/or long delay in combination with detection enhancements (MADIT-RIT-Arm C) are associated with fewer patients experiencing inappropriate therapies than standard programming (MADIT-RIT-Arm A) during postimplant follow-up of patients with indication for primary prevention device therapy. This paper describes design and analytic plan for the MADIT-RIT trial.

Relevance of Monitoring Atrial Fibrillation in Clinical Practice

The monitoring of atrial fibrillation (AF) is performed using a variety of tools, ranging from the conventional Holter electrocardiogram to modern implantable loop recording with remote data exchange. The main clinical areas in AF where monitoring is crucial for decision-making are catheter and surgical ablation, as well as anticoagulation to prevent strokes. Identifying the patient cohort at risk - e.g., those with subclinical silent AF - is a challenge. In addition, the interaction of AF with implanted devices - e.g. AF-triggered inadequate shock therapy - should be the object of continuous monitoring. The prevention of inadequate shock delivery in particular is of major clinical importance.

Long-term follow-up of prophylactic implantable cardioverter-defibrillator-only therapy: comparison of ischemic and nonischemic heart disease

BACKGROUND

The benefits of primary prophylactic implantable cardioverter-defibrillators (ICDs) are actually debated, as some drawbacks become more apparent and as the natural history of cardiac disease seems to improve. Therefore, contemporary follow-up data of non-trial populations treated according to current guidelines remain necessary. The aim of this study was to evaluate mortality and the occurrence of ICD interventions in patients with coronary artery disease (CAD) and dilated cardiomyopathy (DCM) who received in the recent era a primary prophylactic ICD without resynchronization therapy.

HYPOTHESIS

Survival and event-free rates from appropriate ICD therapy are different between ischemic and nonischemic ICD patients.

METHODS

Prospective cohort study of 427 consecutive primary prevention ICD patients with ischemic or nonischemic heart disease, excluding patients with resynchronization.

RESULTS

Ischemic heart disease was present in 290 patients (68%), nonischemic heart disease in 137 patients (32%). During a median follow-up of 31 months (interquartile range [IQR] 15-45 months), 30 patients (7%) died. Mortality was not different in both disease categories. The incidence of appropriate ICD interventions was similar in CAD and DCM (23% vs 21%). Appropriate ICD intervention occurred more frequently in patients with atrial fibrillation (29% vs 19%). Inappropriate ICD intervention occurred in 11% of patients.

CONCLUSIONS

The clinical course of ischemic and nonischemic heart disease patients treated with a primary prophylactic ICD is similar with respect to mortality and to appropriate and inappropriate ICD interventions, in spite of a younger age at baseline of the DCM patients.

Atrial fibrillation in patients with implantable defibrillators

Atrial fibrillation (AF) is common in patients who have implantable defibrillators and presents some unique challenges and opportunities. AF burden can be assessed more accurately, allowing for evaluation of therapy efficacy (drugs or ablation). It remains to be shown whether home monitoring of defibrillators to detect and treat AF more quickly can reduce cardiovascular and stroke end points. One major goal will be to reduce inappropriate shocks from atrial fibrillation. Otherwise, the goals of therapy remain the same-reduction of symptoms (including heart failure exacerbation and inappropriate implantable cardioverter defibrillator therapies) by controlling rate or rhythm and anticoagulation for stroke prophylaxis.

Inappropriate implantable cardioverter-defibrillator shocks in MADIT II: frequency, mechanisms, predictors, and survival impact

OBJECTIVES

This study sought to identify the incidence and outcome related to inappropriate implantable cardioverter-defibrillator (ICD) shocks, that is, those for nonventricular arrhythmias.

BACKGROUND

The MADIT (Multicenter Automatic Defibrillator Implantation Trial) II showed that prophylactic ICD implantation improves survival in post-myocardial infarction patients with reduced ejection fraction. Inappropriate ICD shocks are common adverse consequences that may impair quality of life.

METHODS

Stored ICD electrograms from all shock episodes were adjudicated centrally. An inappropriate shock episode was defined as an episode during which 1 or more inappropriate shocks occurred; another inappropriate ICD episode occurring within 5 min was not counted. Programmed parameters for patients with and without inappropriate shocks were compared.

RESULTS

One or more inappropriate shocks occurred in 83 (11.5%) of the 719 MADIT II ICD patients. Inappropriate shock episodes constituted 184 of the 590 total shock episodes (31.2%). Smoking, prior atrial fibrillation, diastolic hypertension, and antecedent appropriate shock predicted inappropriate shock occurrence. Atrial fibrillation was the most common trigger for inappropriate shock (44%), followed by supraventricular tachycardia (36%), and then abnormal sensing (20%). The stability detection algorithm was programmed less frequently in patients receiving inappropriate shocks (17% vs. 36%, p = 0.030), whereas other programming parameters did not differ significantly from those without inappropriate shocks. Importantly, patients with inappropriate shocks had a greater likelihood of all-cause mortality in follow-up (hazard ratio 2.29, p = 0.025).

CONCLUSIONS

Inappropriate ICD shocks occurred commonly in the MADIT II study, and were associated with increased risk of all-cause mortality.

Does the rate of inappropriate therapy differ in implantable cardioverter–defibrillators from different manufacturers?

OBJECTIVE

We conducted this study to compare the rate of >/=1 inappropriate therapy between ICDs from two manufacturers which use different discriminatory protocols.

METHOD

One hundred sixty two patients (mean age 58 +/- 13 years, 126 male) who received ICDs between January 2001 and 2005 were included in the study. Clinical, electrocardiographic, and ICD stored data and electrograms were collected and analyzed. Immediately after implantation all the detection and discrimination criteria were activated with the nominal values in order to compare the two discriminatory protocols under the default manufacturer's settings.

RESULTS

During the follow up period of 14.3 +/- 10 months, 49 (30%) patients received >/=1 inappropriate ICD therapy. The rate of >/=1 inappropriate ICD therapy in manufacturer A and B ICDs was 26% (n = 29) and 41% (n = 20), respectively. Comparing the rate of >/=1 inappropriate ICD therapy between the two groups by Kaplan-Meier analysis and the log rank test resulted in P = 0.04.

CONCLUSION

Having all discriminatory variables activated with the nominal values, discriminatory performance differs between the two manufacturers. Further larger-scale studies are warranted to prospectively compare the performance of various available ICDs' discriminatory protocols, and define the optimum combination of discriminators in each ICD to decrease the rate of inappropriate therapy.

Evaluation of morphology discrimination for ventricular tachycardia diagnosis in implantable cardioverter-defibrillators

BACKGROUND

To reduce inappropriate therapy from implantable cardioverter-defibrillators (ICDs), electrogram morphology discrimination has been developed to improve arrhythmia discrimination without compromising device safety.

OBJECTIVES

The purpose of this study was to determine the accuracy of the morphology discrimination algorithm for detecting ventricular tachycardia (VT).

METHODS

Stored electrograms of 795 tachyarrhythmias from 106 patients with a St. Jude Medical ICD (51 single-chamber and 55 dual-chamber) were analyzed by the investigators. The data were analyzed for morphology discrimination alone, sudden onset and stability, and morphology discrimination in combination with sudden onset and stability. Data were corrected for multiple episodes within a patient with the generalized estimating equation method.

RESULTS

Using the nominal template match of 60%, morphology discrimination alone provided sensitivity and specificity of 78% and 95% for single-chamber ICDs and 63% and 92% for dual-chamber ICDs, respectively. Based on the receiver operator characteristic curve, the optimal-match percent threshold was 80% to 85% but at the expense of specificity. Morphology discrimination combined with sudden onset and stability increased sensitivity to 98% with specificity of 86% in single-chamber devices. In dual-chamber devices, the loss in sensitivity is compensated by rate branch analysis, yielding a sensitivity of 98%.

CONCLUSION

Arrhythmia discrimination based on electrogram morphology has the potential to reject atrial tachyarrhythmias. However, there is a risk for underdetection of ventricular tachyarrhythmias if arrhythmia discrimination is primarily based on morphology. To guarantee patient safety in single-chamber devices, the morphology discrimination algorithm must be programmed in combination with established detection algorithms. In dual-chamber devices, loss of sensitivity is compensated by the V > A rate branch.

Dual-Chamber Versus Single-Chamber Detection Enhancements for Implantable Defibrillator Rhythm Diagnosis

BACKGROUND

Delivery of inappropriate shocks caused by misdetection of supraventricular tachycardia (SVT) remains a substantial complication of implanted cardioverter/defibrillator (ICD) therapy. Whether use of optimally programmed dual-chamber ICDs lowers this risk compared with that in single-chamber ICDs is not clear.

METHODS AND RESULTS

Subjects with a clinical indication for ICD (n=400) at 27 participating centers received dual-chamber ICDs and were randomly assigned to strictly defined optimal single- or dual-chamber detection in a single-blind manner. Programming minimized ventricular pacing. The primary end point was the proportion of SVT episodes inappropriately detected from the time of programming until crossover or end of study. On a per-episode basis, 42% of the episodes in the single-chamber arm and 69% of the episodes in the dual-chamber arm were due to SVT. Mortality (3.5% in both groups) and early study withdrawal (14% single-chamber, 11% dual-chamber) were similar in both groups. The rate of inappropriate detection of SVT was 39.5% in the single-chamber detection arm compared with 30.9% in the dual-chamber arm. The odds of inappropriate detection were decreased by almost half with the use of the dual-chamber detection enhancements (odds ratio, 0.53; 95% confidence interval, 0.30 to 0.94; P=0.03).

CONCLUSIONS

Dual-chamber ICDs, programmed to optimize detection enhancements and to minimize ventricular pacing, significantly decrease inappropriate detection.

The role of remote monitoring in the reduction of inappropriate implantable cardioverter defibrillator therapies

Implantable cardioverter defibrillators (ICDs) with the integrated Home Monitoring feature use dedicated mobile phone and internet links to provide the physicians and technicians in the ICD clinic with the essential device- and arrhythmia-related data stored in the ICD diagnostic memory. Various counters, graphs and intracardiac electrograms are automatically transmitted via Home Monitoring each day to allow prompt, remote presentation of arrhythmias or detection of technical problems. One of the most inconvenient side-effects of the ICD therapy is inappropriate intervention of the device. Home Monitoring data can help the physician to identify and subsequently reduce the incidence of inappropriate ICD therapy.

[Home Monitoring with implantable ICD--a diagnostic innovation?]

In recent years the rate of ICD implantation has grown substantially after the results of primary and secondary prevention trails have shown significant improvement in mortality and morbidity. However, the increasing number of patients with ICD indication leaves the implanting centres with large logistic problems, esp. with the number of follow-up visits. To further ensure high quality standard in therapy management new follow up routines have to be considered. Possible help may come with new methods of telecardiology, which are presently being introduced into clinical practice. Those systems differ in the way that they are capable to substitute a routine follow up and/ or deliver continuous diagnostic and device status information. Maybe the most promising solution is Home Monitoring in which the implant sends automatically daily messages with regard to therapy and ICD/CRT status without any cooperation of the patient. Interaction of the physician can be triggered by patient individual event filter. By utilizing this features in combination with event related IEGM Online Data physician are able to guide patients more effectively.

Psychosocial Issues of Patients With Implantable Cardioverter Defibrillators

Use of implantable cardioverter defibrillators has become standard therapy for patients at high risk for life-threatening ventricular arrhythmias. Although acceptance of the device is generally high among patients and their families, quality of life and psychosocial issues associated with use of the defibrillators deserve greater attention to improve outcomes. Psychosocial issues, their ramifications, and theory-and evidence-based approaches to improving outcomes are described.