Single-brand dual-chamber discriminators to prevent inappropriate shocks in patients implanted with prophylactic implantable cardioverter defibrillators: a propensity-weighted comparison of single- and dual-chamber devices

Successful Identification of and Discrimination Between Atrial and Ventricular Arrhythmia with the Aid of Pacing and Defibrillator Devices

The presence of supraventricular tachycardia is the leading cause of inappropriate shock in ICD recipients, and it can be a significant cause of morbidity, psychological distress and worsened clinical outcome. Modern pacing and ICD systems offer a number of discriminators that are integrated into algorithms to differentiate sustained ventricular tachycardia from supraventricular tachycardia. These algorithms can be adapted and optimised for each individual patient to ensure that only those arrhythmias that need treatment through the use of an ICD, are actually treated. This review summarises the single- and dual-chamber discriminators that can be used in the detection and classification of tachyarrhythmias.

Long-Term Outcomes Among a Nationwide Cohort of Patients Using an Implantable Cardioverter-Defibrillator: UMBRELLA Study Final Results

Background

Large‐scale studies describing modern populations using an implantable cardioverter‐defibrillator (ICD) are lacking. We aimed to analyze the incidence of arrhythmia, device interventions, and mortality in a broad spectrum of real‐world ICD patients with different heart disorders.

Methods and Results

The UMBRELLA study is a prospective, multicenter, nationwide study of contemporary patients using an ICD followed up by remote monitoring, with a blinded review of arrhythmic episodes. From November 2005 to November 2017, 4296 patients were followed up. After 46.6±27.3 months, 16 067 episodes of sustained ventricular arrhythmia occurred in 1344 patients (31.3%). Appropriate ICD therapy occurred in 27.3% of study population. Patients with ischemic cardiomyopathy (hazard ratio [HR], 1.51; 95% CI, 1.29–1.78), dilated cardiomyopathy (HR, 1.28; 95% CI, 1.07–1.53), and valvular heart disease (HR, 1.94; 95% CI, 1.43–2.62) exhibited a higher risk of appropriate ICD therapies, whereas patients with hypertrophic cardiomyopathy (HR, 0.72; 95% CI, 0.54–0.96) and Brugada syndrome (HR, 0.25; 95% CI, 0.14–0.45) showed a lower risk. All‐cause death was 13.4% at follow‐up. Ischemic cardiomyopathy (HR, 3.09; 95% CI, 2.58–5.90), dilated cardiomyopathy (HR, 3.33; 95% CI, 2.18–5.10), and valvular heart disease (HR, 3.97; 95% CI, 2.25–6.99) had the worst prognoses. Delayed high‐rate detection was enabled in 39.7% of patients, and single‐zone programming occurred in 52.6% of primary prevention patients. Both parameters correlated with lower risk of first appropriate ICD therapy, with no excess risk of mortality. The rate of inappropriate shocks at follow‐up was low (6%) and did not differ among type of ICD but was lower in SmartShock‐capable devices.

Conclusions

Irrespective of the cause, contemporary ICD patients with heart failure–related disorders had a similar risk of ICD life‐saving interventions and death. Current ICD programming recommendations still need to be implemented.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NTC01561144.

Over- and undersensing-pitfalls of arrhythmia detection with implantable devices and wearables

Cardiac implantable electronic devices (CIEDs) are a cornerstone of arrhythmia and heart failure detection as well as management. In recent years new kinds of devices have emerged which can be used subcutaneously or worn on the skin. In particular for large-scale arrhythmia monitoring, small, unobtrusive gadgets seem positioned to upend paradigms and care delivery. However, the performance of CIEDs and wearables is only as good as their sensing and detection capacities. Whether for pacing, defibrillation or diagnostic monitoring, the device must be able to process and filter the sensed signal to reduce noise and to exclude irrelevant physiological signals. The demands on sensing and detection quality will differ depending on how the information is applied. With a pacemaker or implantable cardioverter/defibrillator, withheld or erroneous therapy can have severe consequences and accurate and reliable detection of cardiac function is crucial. Monitoring devices are usually used in risk assessment and management, with greater tolerance for isolated artefacts or lower quality of readings. This review discusses sensing and detection and the performance to date by CIEDs as well as subcutaneous and wearable devices.