Efficacy and Safety of Appropriate Shocks and Antitachycardia Pacing in Transvenous and Subcutaneous Implantable Defibrillators: An Analysis of All Appropriate Therapy in the PRAETORIAN trial

Background: The PRAETORIAN trial showed non-inferiority of the subcutaneous implantable cardioverter-defibrillator (S-ICD) compared to the transvenous ICD (TV-ICD) with regard to inappropriate shocks and complications. In contrast to the TV-ICD, the S-ICD cannot provide antitachycardia pacing (ATP) for monomorphic ventricular tachycardia (VT). This pre-specified secondary analysis evaluates appropriate therapy and whether ATP reduces the number of appropriate shocks. Methods: The PRAETORIAN trial was an international, investigator-initiated randomized trial, which included patients with an indication for ICD therapy. Patients with prior VTs below 170 bpm or refractory recurrent monomorphic VTs were excluded. In 39 centers, 849 patients were randomized to receive an S-ICD (N=426) or TV-ICD (N=423) and were followed for a median of 49.1 months. ICD programming was mandated by protocol. Appropriate ICD therapy was defined as therapy for ventricular arrhythmias. Arrhythmias were classified as discrete episodes and storm episodes (≥3 episodes within 24 hours). Analyses were performed in the modified intention-to-treat population. Results: In the S-ICD group, 86/426 patients received appropriate therapy, versus 78/423 patients in the TV-ICD group, during a median follow-up of 52 months (48-month Kaplan-Meier estimates 19.4% and 17.5%, P=0.45). In the S-ICD group, 83 patients received at least one shock, versus 57 patients in the TV-ICD group (48-month Kaplan-Meier estimates 19.2% and 11.5%, P=0.02). Patients in the S-ICD group had a total of 254 shocks, compared to 228 shocks in the TV-ICD group (P=0.68). First shock efficacy was 93.8% in the S-ICD group and 91.6% in the TV-ICD group (P=0.40). The first ATP attempt successfully terminated 46% of all monomorphic VTs, but accelerated the arrhythmia in 9.4%. Ten S-ICD patients experienced 13 electrical storms, versus 18 TV-ICD patients with 19 electrical storms. Patients with appropriate therapy had an almost two-fold increased relative risk of electrical storms in the TV-ICD group compared to the S-ICD group (P=0.05). Conclusions: In this trial, no difference was observed in shock efficacy of the S-ICD compared with the TV-ICD. Although patients in the S-ICD group were more likely to receive an ICD shock, the total number of appropriate shocks was not different between the two groups.

Impact of COVID-19 Pandemic on Severe Ventricular Arrhythmia and Icd Therapy

BACKGROUND AND OBJECTIVES: The regular clinical follow-up of the patient with the implantable cardioverter-defibrillator (ICD) device was seriously affected by the COVID-19 outbreak. Due to the high risk of contamination, patients didn’t admit to the clinics for the ICD device control. It has been observed that arrhythmic events increased during the COVID-19 outbreak. In this study, we aimed to investigate the frequency of severe ventricular arrhythmias and ICD device therapy in COVID-19 patients with ICD.METHODS: In this single center-observational study, we assessed severe ventricular arrhytmias and ICD therapies by analyzing recorded data of 33 patients (24 males, 72.7%) 3 months before and after getting COVID-19 during the COVID-19 pandemic in Van, Turkey, between 15 August 2020 and 15 January 2021. RESULTS: Before the diagnosis of COVID-19, 6 ventricular tachycardias and 1 ventricular fibrillation were observed. When we analyzed the records after the diagnosis COVID-19, 17 ventricular tachycardia and 3 ventricular fibrillation episodes were observed. Considering the the ICD device therapies, 5 of these severe tachyarrhythmias were terminated by antitachycardia pacing (ATP) and 2 with shock therapy before the diagnosis of COVID-19. After the COVID-19, 14 of them were terminated by ATP and 6 of them ere terminated by shock therapy.CONCLUSION: The effects of the COVID-19 pandemic, especially on ventricular arrhythmia, have not been reported sufficiently. In our study, it was observed that life-threatening ventricular arrhythmias and the ICD therapies were increased in patients with COVID-19, especially in the first month after the diagnosis COVID-19.

Slow VT treatment in a contemporary population of primary prevention ICD recipients

Funding Acknowledgements Type of funding sources: None. Background Implantable cardioverter defibrillator (ICD) is an effective therapy for sudden cardiac death (SCD). 2015 HRS/EHRA/APHRS/SOLAECE expert consensus document suggests long VT detection, above 185 bpm, as optimal ICD programming to reduce unnecessary therapies in primary prevention (PP). Purpose The aim of our study is to evaluate incidence, safety and efficacy of ICD treatment for VT arrhythmias below 185 bpm, in a contemporary population of PP ICD recipients with long detection intervals (LDI), morphological discrimination algorithm and antitachycardia pacing therapies (ATP) before shock. Methods We conducted a single centre retrospective study enrolling 236 patients implanted with a primary-prevention indication from January 2013 to June 2019. Patients were implanted with single or dual chamber single-lead transvenous ICD. All patients had standard device setting with long (at least 20 s in VT and 7 s in VF) VT/VF detection above 150 bpm and therapies starting from 171 with up to 5 ATP and multiple shocks. PainFREE-like bursts and Schaumann-like ramps ATP were always set in VT zone. Of each patient we collected a detailed report of up to five appropriate events and three inappropriate events. Arrhythmia diagnosis was confirmed from 3 independent expert physicians. Date of the event, cycle length, type of morphology (polymorphic or monomorphic), therapies with their effect were collected. Results During a mean follow-up of 42 months, 47 (20 %) and 18 (8%) patients had at least one appropriate and inappropriate activation, respectively. The detailed-events analysis shows that 16 (7%) patients had 38 (30%) appropriate events with rate <188 bpm. At these rate ATP were 97% effective. 14 (38%) of inappropriate activations were caused by arrythmias with ventricular rate below 188 bpm and half of these received a shock; 30% of inappropriate shocks were due to arrhythmia with rate <188 bpm. 73% of treated events, with rate <188 bpm, were appropriate. Only 5.6% (n = 10) of ATP attempts cause arrhythmia acceleration. Conclusions One third of detected arrhythmias had a rate below 188 bpm and 73% were true VT. In this slow VT zone, ATP had a high success rate with low percentage of acceleration.

Malignant arrythmic storm, stellate ganglion and diabetes mellitus

Funding Acknowledgements Type of funding sources: None. Introduction Malignant arrhythmic storm (MAS) increases mortality more than three-fold according to current data. In the acute setting, besides resolving reversible causes, antiarrhythmics are the mainstay of treatment. The role of suppressing the local sympathetic nervous system activity, using stellate ganglion block (SGB) for example, is still being investigated. Purpose To show short-term efficacy of SGB in suppressing the ventricular arrhythmia recurrence in MAS. To identify subgroups of patients with better clinical response after SGB. Methods All consecutive patients with MAS, with standard treatment failure and ventricular arrhythmia recurrence, treated with ultrasound guided SGB, instilating 7ml of 0,5% Bupivacain. 58 MAS treated with SGB durin 2017 – 2020. There were 49 men (84,5%), average age 68,7 +/- 11,4, with average left ventricular EF 28,9 +/- 8,43%. There were 17 diabetics (29,3%). Results When we compare the numbers of defibrillations for sustained ventricular tachycardia 48 hours before and 48 hours after SGB, being the primary therapeutic endpoint in MAS, we see a 96,7% reduction (p < 0,001). When we evaluate ventricular arrhythmias treated with both antitachycardia pacing and shocks, then we see 90% reduction (p < 0,001). The effect of SGB in ventricular arrhythmia suppression was statistically significant during the entire follow-up of 8 days. When we analyzed the cohort, looking for groups showing better response after SGB in terms of ventricular arrhythmia reduction, the only group showing statistical significance in this regard are patients with diabetes mellitus. Conclusions In our cohort, stellate ganglion block is exceptionally effective in the treatment algorithm of malignant arrhythmic storm. SGB shows significantly higher efficacy in the subgroup of patients with diabetes mellitus. Abstract Figure. VA before and after BSG

The Extravascular Implantable Cardioverter-Defibrillator: The Pivotal Study Plan

Background: Transvenous implantable cardiac defibrillators (TV ICD) provide life-saving therapy for millions of patients worldwide. However, they are susceptible to several potential short- and long- term complications including cardiac perforation and pneumothorax, lead dislodgement, venous obstruction, and infection. The extravascular ICD (EV ICD) system’s novel design and substernal implant approach avoids the risks associated with TV ICDs while still providing pacing features and similar generator size to TV ICDs. Study Design: The EV ICD pivotal study is a prospective, multi-center, single-arm, non-randomized, pre-market clinical study designed to examine the safety and acute efficacy of the system. This study will enroll up to 400 patients with a Class I or IIa indication for implantation of an ICD. Implanted subjects will be followed up to approximately 3.5 years, depending on when the patient is enrolled. Objective: The clinical trial is designed to demonstrate safety and effectiveness of the EV ICD system in human use. The safety endpoint is freedom from major complications, while the efficacy endpoint is defibrillation success. Both endpoints will be assessed against prespecified criteria. Additionally, this study will evaluate antitachycardia pacing (ATP) performance, electrical performance, extracardiac pacing sensation, asystole pacing, appropriate and inappropriate shocks, as well as a summary of adverse events. Conclusion: The EV ICD pivotal study is designed to provide clear evidence addressing the safety and efficacy performance of the EV ICD System.