Presentation and prognosis of excessive asymptomatic atrial ectopy in children and adolescents with structurally and functionally normal hearts

Excessive premature atrial complexes (PACs) in pediatric patients with a structurally normal heart are presumed to be benign and self-resolving, but no studies have confirmed this. Adults with excessive PACs, however, are at increased risk for future sustained atrial arrhythmias and cardiovascular morbidity and mortality. Therefore, we sought to evaluate the clinical course of frequent PACs in asymptomatic children. Patients \u3c 21 years old with numerous asymptomatic PACs (\u3e50/24 hours) were retrospectively selected over a 10-year period. Demographics, clinical characteristics, and results of cardiovascular testing were tabulated. Two groups were defined: those with a significant (\u3e20%) reduction in burden of atrial ectopy versus those with an insignificant (\u3c20%) reduction or increase. Of 6,902 patients, 343 patients (5%) met criteria. Initial median age was 8.3 (interquartile range [IQR] 4.1 to 14) years with comparable male:female ratio. Follow-up Holters were performed on 188 patients (54.8%) at a median interval of 2.2 (IQR 1.3 to 3.6) years. Overall, there was a significant decrease in atrial ectopy burden from 4.2% (IQR 1.9 to 6.5) down to 0.5% (IQR 0.01 to 2.3), with 166 patients (88.3%), demonstrating a decrease of over 20%. Five percent had a small increase, and 6% had an insignificant decrease. None developed cardiac symptoms or sustained supraventricular tachydysrhythmia. Male gender, athletic participation, and discontinuation of stimulant medications were the chief predictors for a reduction of PAC burden on follow-up. Atrial triplets at presentation were associated with a 5.4% increase. In conclusion, this study confirms that excessive asymptomatic childhood PACs with structurally normal hearts are rare and short-term to medium-term prognosis is benign

Computerized electrocardiogram data transformation enables effective algorithmic differentiation of wide QRS complex tachycardias

BACKGROUND: Accurate automated wide QRS complex tachycardia (WCT) differentiation into ventricular tachycardia (VT) and supraventricular wide complex tachycardia (SWCT) can be accomplished using calculations derived from computerized electrocardiogram (ECG) data of paired WCT and baseline ECGs. OBJECTIVE: Develop and trial novel WCT differentiation approaches for patients with and without a corresponding baseline ECG. METHODS: We developed and trialed WCT differentiation models comprised of novel and previously described parameters derived from WCT and baseline ECG data. In Part 1, a derivation cohort was used to evaluate five different classification models: logistic regression (LR), artificial neural network (ANN), Random Forests [RF], support vector machine (SVM), and ensemble learning (EL). In Part 2, a separate validation cohort was used to prospectively evaluate the performance of two LR models using parameters generated from the WCT ECG alone (Solo Model) and paired WCT and baseline ECGs (Paired Model). RESULTS: Of the 421 patients of the derivation cohort (Part 1), a favorable area under the receiver operating characteristic curve (AUC) by all modeling subtypes: LR (0.96), ANN (0.96), RF (0.96), SVM (0.96), and EL (0.97). Of the 235 patients of the validation cohort (Part 2), the Solo Model and Paired Model achieved a favorable AUC for 103 patients with (Solo Model 0.87; Paired Model 0.95) and 132 patients without (Solo Model 0.84; Paired Model 0.95) a corroborating electrophysiology procedure or intracardiac device recording. CONCLUSION: Accurate WCT differentiation may be accomplished using computerized data of (i) the WCT ECG alone and (ii) paired WCT and baseline ECGs

Infection in patients with subcutaneous implantable cardioverter-defibrillator: Results of the S-ICD Post Approval Study

BACKGROUND: Early subcutaneous implantable cardioverter-defibrillator (S-ICD) studies included atypical cohorts of patients who were younger with fewer comorbidities. Recent S-ICD studies included patient populations with more comorbidities. OBJECTIVES: The goals of this study were to determine the incidence and predictors of S-ICD-related infection over a 3-year follow-up period and to use these results to develop an infection risk score. METHODS: The S-ICD Post Approval Study is a US prospective registry of 1637 patients. Baseline demographic characteristics and outcomes with 3-year postimplantation follow-up were compared between patients with and without device-related infection. A risk score was derived from multivariable proportional hazards analysis of 22 variables. RESULTS: Infection was observed in 55 patients (3.3%), with 69% of infections occurring within 90 days and a vast majority (92.7%) within 1 year of implantation. Late infections more likely involved device erosion; no infections occurred after year 2. The annual mortality rate postinfection was 0.6%/y. No lead extraction complications or bacteremia related to infection were observed. An infection risk score was created with diabetes, age, prior transvenous ICD implant, and ejection fraction as predictors. Patients with a risk score of ≥3 had an 8.8 hazard ratio (95% confidence interval 2.8-16.3) of infection compared with a 0 risk score. CONCLUSION: Infection rates in the S-ICD Post Approval Study were similar to other S-ICD populations and not associated with systemic blood-borne infections. Late infection (\u3e1 year) is uncommon and associated with system erosion. A high-risk infection cohort can be identified that may facilitate preventive measures. CLINCALTRIALS. GOV IDENTIFIER: NCT01736618

Defibrillation effectiveness and safety of the shock waveform used in a contemporary wearable cardioverter defibrillator: Results from animal and human studies.

IntroductionThe wearable cardioverter defibrillator (WCD) is used to protect patients at risk for sudden cardiac arrest. We examined defibrillation efficacy and safety of a biphasic truncated exponential waveform designed for use in a contemporary WCD in three animal studies and a human study.MethodsAnimal (swine) studies: #1: Efficacy comparison of a 170J BTE waveform (SHOCK A) to a 150J BTE waveform (SHOCK B) that approximates another commercially available waveform. Primary endpoint first shock success rate. #2: Efficacy comparison of the two waveforms at attenuated charge voltages in swine at three prespecified impedances. Primary endpoint first shock success rate. #3: Safety comparison of SHOCK A and SHOCK B in swine. Primary endpoint cardiac biomarker level changes baseline to 6 and 24 hours post-shock. Human Study: Efficacy comparison of SHOCK A to prespecified goal and safety evaluation. Primary endpoint cumulative first and second shock success rate. Safety endpoint adverse events.ResultsAnimal Studies #1: 120 VF episodes in six swine. First shock success rates for SHOCK A and SHOCK B were 100%; SHOCK A non-inferior to SHOCK B (entire 95% CI of rate difference above -10% margin, p ConclusionsThe BTE waveform effectively and safely terminated induced VF in swine and a small sample in humans.Trial registrationHuman study clinical trial registration: URL: https://clinicaltrials.gov; Unique identifier: NCT04132466