Programming ICDs in the Modern Era beyond Out-of-the Box Settings

Prediction of Sudden Death Risk in Patients with Congenital Heart Diseases

Risk stratification for sudden death should be discussed with patients with congenital heart disease at each stage of personal and cardiac development. For most patients, risk is low through teenage years and the critical factors to consider are anatomy, ventricular function, and symptoms. By adulthood, these are supplemented by screening for atrial arrhythmias, ventricular arrhythmias, and pulmonary hypertension. Therapies include medication, ablation, and defibrillator placement.

Comparison of burst versus ramp antitachycardia pacing therapy for ventricular tachycardia: A meta-analysis

Current guidelines recommend at least one attempt of defibrillator antitachycardia pacing (ATP) therapy, showing preference for burst therapy. The objective of this study is to compare ramp versus burst ATP therapy proportion of success and acceleration in treating spontaneous or induced ventricular tachycardia (VT). The review protocol was previously published in PROSPERO. Data synthesis and measures of heterogeneity (I² ) was performed by CMA® software v.3 comparing proportions in both groups. Sensitivity analysis was performed as subgroup or meta-regression according to quality, clinical characteristics, and differences in design. Thirteen studies including 30,117 VT episodes in 1672 patients were analyzed. There was no significant difference in the proportion of success between burst and ramp therapy in spontaneous VT (odds ratio = 1.116; 95% confidence interval [CI] = 0.788-1.579; I²  = 89%). There was no significant difference in the proportion of success between burst and ramp therapy in induced VT (odds ratio = 0.820; 95% CI = 0.468-1.437; I²  = 93%). No significant difference was found in the proportion of acceleration between burst and ramp in spontaneous VT (odds ratio = 0.792; 95% CI = 0.476-1.317; I²  = 83%). No significant difference was found in the proportion of acceleration between burst and ramp in induced VT (odds ratio = 1.234; 95% CI = 0.802-1.898; I²  = 55%). Sensitivity analysis did not change main results. There is no difference in success or in acceleration proportion between burst or ramp ATP therapy irrespective if the VT was spontaneous or induced. Future implantable cardioverter defibrillator programming guidelines should offer both ATP therapies without preference in one of them.

Impact of device programming on the success of the first anti-tachycardia pacing therapy: An anonymized large-scale study

Background

Antitachycardia pacing (ATP) is an effective treatment for ventricular tachycardia (VT). We evaluated the efficacy of different ATP programs based on a large remote monitoring data set from patients with implantable cardioverter-defibrillators (ICDs).

Methods

A dataset from 18,679 ICD patients was used to evaluate the first delivered ATP treatment. We considered all device programs that were used for at least 50 patients, leaving us with 7 different programs and a total of 32,045 episodes. We used the two-proportions z-test (α = 0.01) to compare the probability of success and the probability for acceleration in each group with the corresponding values of the default setting.

Results

Overall, the first ATP treatment terminated in 78.4%–97.5% of episodes with slow VT and 81.5%–91.1% of episodes with fast VT. The default setting of the ATP programs with the number of sequences S = 3 was applied to treat 30.1% of the slow and 36.6% of the fast episodes. Reducing the maximum number of sequences to S = 2 decreased the success rate for slow VT (P < 0.0001, h = 0.38), while the setting S = 4 resulted in the highest success rate of 97.5% (P < 0.0001, h = 0.27).

Conclusion

While the default programs performed well, we found that increasing the number of sequences from 3 to 4 was a promising option to improve the overall ATP performance.

Predicting electrical storms by remote monitoring of implantable cardioverter-defibrillator patients using machine learning

Aims

Electrical storm (ES) is a serious arrhythmic syndrome that is characterized by recurrent episodes of ventricular arrhythmias. Electrical storm is associated with increased mortality and morbidity despite the use of implantable cardioverter-defibrillators (ICDs). Predicting ES could be essential; however, models for predicting this event have never been developed. The goal of this study was to construct and validate machine learning models to predict ES based on daily ICD remote monitoring summaries.

Methods and results

Daily ICD summaries from 19 935 patients were used to construct and evaluate two models [logistic regression (LR) and random forest (RF)] for predicting the short-term risk of ES. The models were evaluated on the parts of the data not used for model development. Random forest performed significantly better than LR (P < 0.01), achieving a test accuracy of 0.96 and an area under the curve (AUC) of 0.80 (vs. an accuracy of 0.96 and an AUC of 0.75). The percentage of ventricular pacing and the daytime activity were the most relevant variables in the RF model.

Conclusion

The use of large-scale machine learning showed that daily summaries of ICD measurements in the absence of clinical information can predict the short-term risk of ES.

Competitive athletes with implantable cardioverter-defibrillators-How to program? Data from the Implantable Cardioverter-Defibrillator Sports Registry

BACKGROUND

Athletes with an implantable cardioverter-defibrillator (ICD) may require unique optimal device-based tachycardia programming.

OBJECTIVE

The purpose of this study was to assess the association of tachycardia programming characteristics of ICDs with occurrence of shocks, transient loss-of-consciousness, and death among athletes.

METHODS

A subanalysis of a prospective, observational, international registry of 440 athletes with ICDs followed for a median of 44 months was performed. Programming characteristics were divided into groups for rate cutoff (very high, high, or low) and detection (long-detection interval [>nominal] or nominal). Endpoints included total, appropriate, and inappropriate shocks, transient loss-of-consciousness, and mortality.

RESULTS

In this cohort, 62% were programmed with high-rate cutoff and 30% with long detection. No athlete died of an arrhythmia (related or unrelated) to ICD shocks. Three patients had sustained ventricular tachycardia below programmed detection rate, presenting as palpations and/or dizziness. ICD shocks were received by 98 athletes (64 appropriate, 32 inappropriate); 2 patients received both. Programming a high-rate cutoff was associated with decreased risk of total (P = .01) and inappropriate (P = .04) shocks overall and during competition or practice. Programming long-detection intervals was associated with fewer total shocks. Single- vs dual-chamber devices and the number of zones were unrelated to risk of shock. Transient loss-of-consciousness, associated with 27 appropriate shocks, was not related to programming characteristics.

CONCLUSION

High-rate cutoff and long-detection duration programming of ICDs in athletes at risk for sudden death can reduce total and inappropriate ICD shocks without affecting survival or the incidence of transient loss-of-consciousness.

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.

Inappropriate ICD Shocks - When Monitoring Zones Do More Than Monitor

The ventricular tachycardia (VT) monitoring zone in implantable cardioverter defibrillators (ICDs) is usually programmed to detect slow VTs. However, it is not well known whether programming this zone can affect the ICD arrhythmia redetection or confirmation criteria. We report two cases of inappropriate ICD shocks due to the programming of a slow VT monitoring zone in the same device model.

Implantable cardioverter defibrillator harm?

Despite the general acceptance of implantable cardioverter defibrillator (ICD) therapy [including cardiac resynchronization therapy defibrillator (CRT-D)] among cardiologists, there has been some recent concern about potential harm associated with ICDs, particularly related to quality of life and possible adverse effects of ICD shocks. These and others undeniably constitute complications of ICD therapy paper. However, the evidence from multiple ICD/CRT-D trials, which take into account complications on the one side, and benefits on the other, speaks strongly in favour of patients receiving net benefit, rather than harm. And this is true for (i) prognosis, (ii) effects of shocks, and (iii) quality of life. Moreover--addressing specifically the complications aspects--there have been major advances, both in the technology of the systems and in physician practice, which have put major focus on minimizing shocks (appropriate and inappropriate) in favour of antitachycardia pacing. In addition, the tendency is that more and more of such patients receive devices incorporating cardiac resynchronization pacing, now proven to delay and/or minimize heart failure. There is now a large body of evidence, particularly in recent years with improved technology, that, rather than 'harm', the ICD/CRT-D provides substantial protection for appropriately selected patients.