Defibrillators

Background and aimsRisk stratification of sudden cardiac death after myocardial infarction and prevention by defibrillator rely on left ventricular ejection fraction (LVEF). Improved risk stratification across the whole LVEF range is required for decision-making on defibrillator implantation.MethodsThe analysis pooled 20 data sets with 140 204 post-myocardial infarction patients containing information on demographics, medical history, clinical characteristics, biomarkers, electrocardiography, echocardiography, and cardiac magnetic resonance imaging. Separate analyses were performed in patients (i) carrying a primary prevention cardioverter-defibrillator with LVEF ≤ 35% [implantable cardioverter-defibrillator (ICD) patients], (ii) without cardioverter-defibrillator with LVEF ≤ 35% (non-ICD patients ≤ 35%), and (iii) without cardioverter-defibrillator with LVEF > 35% (non-ICD patients >35%). Primary outcome was sudden cardiac death or, in defibrillator carriers, appropriate defibrillator therapy. Using a competing risk framework and systematic internal-external cross-validation, a model using LVEF only, a multivariable flexible parametric survival model, and a multivariable random forest survival model were developed and externally validated. Predictive performance was assessed by random effect meta-analysis.ResultsThere were 1326 primary outcomes in 7543 ICD patients, 1193 in 25 058 non-ICD patients ≤35%, and 1567 in 107 603 non-ICD patients >35% during mean follow-up of 30.0, 46.5, and 57.6 months, respectively. In these three subgroups, LVEF poorly predicted sudden cardiac death (c-statistics between 0.50 and 0.56). Considering additional parameters did not improve calibration and discrimination, and model generalizability was poor.ConclusionsMore accurate risk stratification for sudden cardiac death and identification of low-risk individuals with severely reduced LVEF or of high-risk individuals with preserved LVEF was not feasible, neither using LVEF nor using other predictors.

BackgroundSodium glucose cotransporter 2 inhibitors (SGLT2i) represent one of the four pillars of heart failure (HF) pharmacological therapy.ObjectiveThe study aims to clarify SGLT2i antiarrhythmic effect on patients with HF with reduced ejection fraction (HFrEF) in terms of atrial and ventricular arrhythmias (AAs and VAs) reduction.MethodsHFrEF carriers of implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) followed by remote monitoring of Policlinico Umberto I of Rome for 1 year before and after SGLT2i therapy initiation were enrolled in the study. We compared the incidence of AAs and VAs as recorded at remote monitoring during 1 year preceding SGLT2i therapy initiation and after 1 year of SGLT2i therapy.ResultsAmong 198 enrolled patients, 135 patients had arrhythmic events before SGLT2i therapy prescription. There were 1353 arrhythmic events recorded in the year before SGLT2i therapy prescription, and 354 events were detected in the year after SGLT2i initiation, with a 73.8% reduction in events number after therapy initiation. After SGLT2i therapy initiation, the median number of total arrhythmic episodes significantly decreased from a median of 7 [3;12] to 1 [0;4] (P value ConclusionsIn HFrEF carriers of ICD/CRT-D, the use of SGLT2i resulted in significant reduction of AA and VA events.

BackgroundThe PRAETORIAN trial (A Prospective, Randomized Comparison of Subcutaneous and Transvenous Implantable Cardioverter Defibrillator Therapy) investigated the efficacy and safety of the subcutaneous implantable cardioverter defibrillator (S-ICD) compared with a transvenous ICD (TV-ICD) and showed noninferiority of the S-ICD with regard to the composite end point of device-related complications and inappropriate shocks after 49.1 months. Complications associated with transvenous leads are expected to occur after longer follow-up. The PRAETORIAN-XL trial aims to investigate whether the S-ICD is superior to the TV-ICD with respect to device-related complications at 8-year follow-up.MethodsThe PRAETORIAN trial randomized patients with a class I or IIa indication for ICD therapy without the need for pacing to either S-ICD or TV-ICD among 39 centers in the United States and Europe between March 2011 and January 2017. The follow-up was extended after 49.1 months by an additional 4 years for the PRAETORIAN-XL trial. The primary end point was the composite of all device-related complications. Complications could be related or unrelated to the lead and minor or major, with major complications being those requiring an invasive intervention. End points were analyzed according to the modified intention-to-treat principle using a Fine-Gray subdistribution hazards model to account for competing risks. An as-treated analysis was performed using a Cox proportional hazards model with device type as time-dependent variable.ResultsPatients were randomized to S-ICD (n=426) and TV-ICD (n=423). Twenty-one percent of the S-ICD group versus 18% of the TV-ICD group were women. The median age at implantation was 63 (interquartile range, 54-69) years for the S-ICD and 64 (interquartile range, 56-69) years for the TV-ICD. After a median follow-up of 87.5 months, all device-related complications (major and minor combined) were not significantly different in the modified intention-to-treat analysis (subdistribution hazard ratio, 0.73 [95% CI, 0.48-1.12]); P=0.15). However, TV-ICD patients more often had a major complication or lead-related complication (P=0.03 and PP=0.047).ConclusionsThe PRAETORIAN-XL trial demonstrated that there was no significant difference between the S-ICD and TV-ICD in all device-related complications during long-term follow-up. However, the TV-ICD carries a higher risk of major and lead-related complications compared with S-ICD therapy. The S-ICD should therefore be considered for all patients without a pacing indication who are evaluated for ICD therapy.RegistrationURL: https://www.clinicaltrials.gov; Unique identifier: NCT01296022.

Sudden cardiac death (SCD) remains a major cause of mortality among adults with congenital heart disease (ACHD). Risk stratification for malignant ventricular arrhythmias in this population is challenging because of the heterogeneity of anatomical substrates, lifelong haemodynamic changes, and the limited predictive accuracy of currently risk models. Furthermore, implantation of an implantable cardioverter-defibrillator (ICD) in ACHD patients is frequently complicated by anatomical constraints, limited venous access, and a significant burden of device-related complications, including infection involving prosthetic material. Several transient cardiac or systemic conditions-including haemodynamic deterioration, acquired myocardial disease, infections, inflammatory states, pregnancy, endocrine disturbances, or peri-procedural phases-may temporarily increase arrhythmic risk or impair ventricular function. In these scenarios, the indication for permanent ICD may be uncertain or premature. The wearable cardioverter-defibrillator (WCD) provides a non-invasive option for temporary protection against life-threatening ventricular arrhythmias while allowing time for clinical stabilization, diagnostic reassessment, and individualized decision-making. This review summarizes the pathophysiological rationale, available evidence, and potential clinical applications of WCD therapy in ACHD.