Rates Of Implantable Cardioverter Defibrillator Shocks Research Articles

Predictors of Shock-Reduction Programming and Its Impact on Implantable Cardioverter-Defibrillator Therapies and Mortality: The CERTITUDE Registry.

Shock-reduction implantable cardioverter-defibrillator programming (SRP) was associated with fewer therapies and improved survival in randomized controlled trials, but real-world studies investigating SRP and associated outcomes are limited. The BIOTRONIK CERTITUDE registry was linked with the Medicare database. We included all patients with an implantable cardioverter-defibrillator implanted between August 22, 2012 and September 30, 2021 in the United States. SRP was defined as programming to either a therapy rate cutoff ≥188 beats per minute or number of intervals to detection ≥30/40 for treatment. Among 6781 patients (mean 74±9 years; 27% women), 3393 (50%) had SRP. Older age, secondary prevention indication, and device implantation in the southern or western United States were associated with lower use of SRP. The cumulative incidence rate of implantable cardioverter-defibrillator shocks was lower in the SRP group (5.1% shocks/patient year) compared with the non-SRP group (7.2% shocks/patient year) (adjusted hazard ratio [HR], 0.83 [95% CI, 0.73-0.96]; P=0.005). Over a median follow-up of 2.9 years, 739 deaths occurred in the SRP group and 822 deaths occurred in the non-SRP group (adjusted HR, 0.97 [95% CI, 0.88-1.07]; P=0.569). SRP was associated with a lower all-cause mortality among patients without ischemic heart disease compared with patients with ischemic heart disease (adjusted HR, 0.64 [95% CI, 0.48-0.87] versus adjusted HR, 1.02 [95% CI, 0.92-1.14]; Pinteraction=0.004). Adoption of SRP is low in real-world clinical practice. Age, clinical variables, and geographic factors are associated with use of SRP. In this study, SRP-associated decrease in mortality was limited to patients without ischemic heart disease.

Wearable Cardioverter-Defibrillator Therapy for the Prevention of Sudden Cardiac Death: A Science Advisory From the American Heart Association.

Sudden cardiac death (SCD) accounts for >300 000 deaths in the United States annually.1 Although the majority of these deaths occur in low-risk populations2 in which aggressive interventions are not practical, some higher-risk populations have been established in whom intervention with an implantable cardioverter-defibrillator (ICD) has been shown in randomized trials to reduce mortality.3–7 Additionally, there is a population of patients who may benefit from automatic emergency cardioversion-defibrillation but are not deemed appropriate candidates for ICD implantation at the time of presentation. This group is defined by 2 populations. The first subgroup comprises those who are at perceived risk but for whom there may be optimism for clinical improvement (eg, patients soon after revascularization or those with a recent diagnosis of myocardial infarction [MI] or cardiomyopathy). Alternatively stated, the optimal management of these patients at risk (or perceived risk) during the waiting period before an ICD is indicated remains unknown. The second subgroup includes those who have a clear indication for ICD but also have a contraindication to immediate ICD placement (eg, active infection or unknown prognosis). The wearable cardioverter-defibrillator (WCD) is a device designed for patients at risk of SCD who are not immediate candidates for ICD therapy. By providing automatic therapy, the WCD does not depend on a second person to defibrillate, as required with a manual or automated external defibrillator (AED). Unlike the ICD (including both transvenous and subcutaneous devices), the WCD requires no surgical operation, can be provided for a short period of time, is temporary, and is easily removed. These characteristics of the WCD, along with safety and efficacy data presented to the US Food and Drug Administration (FDA), resulted in approval in the United States in 2002.8 Because of the increasing use of the WCD and uncertainty of indications …

Incidence of defibrillator shocks after elective generator exchange following uneventful first battery life.

BackgroundA significant number of implantable cardioverter‐defibrillator (ICD) patients do not experience shocks after ICD implant. Elective generator exchange (GE) has been associated with increased risk of infection and ICD lead failure. There is a paucity of contemporary data reporting on shock incidence with replacement devices.Methods and ResultsPatients undergoing elective GE (n=24 203) who transmit data remotely via a remote monitoring system were analyzed to determine the incidence of ICD shocks after GE. A total of 16 230 patients (67%) did not experience a shock with the first ICD (group A), and 7973 (33%) received at least 1 shock (group B). Patients in group A were older (71.3 versus 68.8 years, P<0.001) and more often female (71% versus 77% male, P<0.001). Over an average follow‐up of 1.9±1.2 years after GE, the proportion of patients with shocks and risk of ICD shocks was lower for those who did not receive a shock during the first battery life (group A: 9.9% versus 27.7%, hazard ratio 0.36, 95% CI 0.34 to 0.38, P<0.001). The cumulative rate of ICD shocks at 5 years after GE was 25.7% in group A and 51.1% in group B.ConclusionsIn this large cohort of ICD patients implanted across the United States, two thirds did not receive ICD shock therapy prior to GE. The occurrence of ICD shocks prior to GE is an important predictor of shocks after GE; however, even among those without shocks during first battery life, the incidence of shocks at 5 years following GE is >25%. These data should support informed decision making for patients and physicians at the time of ICD generator end of service.

77 * The incidence of appropriate ICD therapy in heart failure patients

Introduction: A major concern for patients receiving an implantable cardioverter defibrillator (ICD) is the rate of ICD shocks. This is an important consideration when counselling a patient prior to implantation but it is challenging to provide an accurate estimate due to the reported heterogeneity of this outcome in clinical trials and the common disjoint between clinical trials and real-world experience. An additional concern for physicians since the publication of MADIT-RIT is the rate of ATP therapy. Contemporary, real-world UK data in heart failure patients is lacking. Aim: We sought to determine the incidence of appropriate ICD therapy in our real world cohort of heart failure patients. Methods: Patients under active ICD follow-up in 2011 and 2012 were identified at two UK tertiary cardiology centres. Patients who had heart failure with an ejection fraction (EF) ≤35% (or severely impaired) were included. Each patient had at least 12 months follow-up data. Results: Data were analysed for 479 patients in 2011 and 537 patients in 2012: median age at implant 67years (IQR 58-73), median EF 25% (IQR 20-30). Underlying aetiologies were ischaemic (74%), DCM (15%) and unknown(11%). Indications were primary prevention (55%), secondary prevention (43%) or not documented (2%). Results are summarised in the table. Conclusions: There was no significant difference in the rates of ICD therapy (shock or ATP) between those patients with a primary or secondary prevention indication. On average the annual rate of appropriate shocks for primary and secondary prevention were 7.7% and 11.5% respectively. Contemporary data detailing rates of appropriate therapy in secondary prevention patients is particularly lacking and our data shows rate of appropriate shocks in the secondary prevention group was much lower than the some older trials (45% in the first year of the AVID trial). This highlights the importance of establishing contemporary event rates in order to best inform patients. Our data would suggest that the rate of ATP in our primary prevention cohort is comparable to that seen in the conventional arm of MADIT-RIT. As such it will be of interest to repeat this data collection now that more conservative programming has been implemented. | | Primary Prevention | Secondary Prevention | Fishers exact test (P=) | | ---------------------- | ------------------ | -------------------- | ----------------------- | | Appropriate shock 2011 | 8.2% | 14.1% | 0.052 | | Appropriate ATP 2011 | 14.3% | 15.7% | 0.743 | | Appropriate shock 2012 | 7.1% | 8.9% | 0.413 | | Appropriate ATP 2012 | 12% | 14.4% | 0.415 | Table showing the proportion of patients receiving ICD therapy annually in 2011/12 categorised by indication for ICD implantation.

Single-chamber ICD, single-zone therapy in primary and secondary prevention patients: the simpler the better?

It is now well established that implantable cardioverter defibrillator (ICD) implantation reduces mortality in patients at increased risk of sudden cardiac death. However, the best programming parameters remain controversial. Our traditional policy has followed a simple approach in the vast majority of patients. In accordance with ICD programming in the major randomized clinical trials, we programmed a single high-rate, shock-only therapy zone. We aimed to demonstrate in this observational study that simple programming is not associated with higher shock rates or mortality when compared to other published studies. Consecutive patients who underwent single-chamber ICD implantation with single-zone, high-rate programming at our institution between 1993 and 2008 were retrospectively studied. Data were collected prospectively in a database regarding details of ICD implantation, demographic data, and indication. Three hundred thirty-two patients were included in our study, 31 % primary prevention and 68 % secondary prevention. Mean ejection fraction (EF) is 33.7 ± 15.3. Over a mean follow-up period of 62.5 ± 38.1 months, 135 patients experienced ICD shock (annualized event rate 7.7 %); 89 patients (26.8 %) appropriate shock in VT-ventricular fibrillation (VF), 68 patients (20.5 %) inappropriate shocks, and 22 patients (6.6 %) both. Twenty-nine patients (8.7 %) were reprogrammed to additional VT-ATP zones. Twenty-two (6.6 %) patients underwent heart transplantation. Sixty-two patients (18.6 %) died during follow-up, 43.6 % out of them due to cardiac cause, mainly progressive heart failure. Our results show that simpler settings with single-zone, high-rate programming is associated with ICD shock rates and long-term mortality that does not appear to be worse when compared with contemporary studies which include multizone ICD programming with antitachycardia pacing activated.