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Background: Sporadic high impedance values without other anomalies detected by remote monitoring of hybrid cardiac implantable electronic device systems have been described recently. The clinical significance and related hazard of this phenomenon are not fully understood., Objective: The purpose of this study was to describe the prevalence, management, and outcomes associated with hybrid implantable cardioverter-defibrillator (ICD) systems., Methods: We collected data on patients with sporadic high lead impedance alert on remote monitoring who had undergone implantation with a hybrid ICD system between January 2015 and December 2019. Pacing thresholds, sensing and impedance values, and temporal pattern of impedance values were collected by remote monitoring, at implantation, and during an in-office visit., Results: Among 92 patients receiving a hybrid ICD, 15 (16.3%) had high impedance alert on remote monitoring (14 Boston Scientific and 1 St. Jude Medical ICD canisters paired with Medtronic or Biotronik DF-1 leads). Four patients had a cardiac resynchronization therapy-defibrillator (CRT-D), 7 a dual-chamber ICD, and 4 a single-chamber ICD. Three patients presented with high atrial lead impedance, 7 high right ventricular lead impedance, 1 high left ventricular impedance, and 2 high shock impedance values. All patients underwent follow-up by remote monitoring. Sporadic high impedance values were not associated with an adverse outcome or need for revision in all but 1 patient, who had continuously increasing pacing thresholds due to lead microfracture., Conclusion: In the absence of clear signs of lead fracture or connection issues, sporadic high pacing and shock impedance in hybrid implantable defibrillator systems can be safely managed by close follow-up., (Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: Despite not being uncommon, limited evidence exists about predisposing factors for venous obstruction in patients with implantable electronic devices. We aimed to assess the prevalence of severe venous obstruction in patients with intravenous devices and identify predictor factors., Methods and Results: A total of 184 patients underwent venography to detect venous obstruction associated with the inserted lead. Vessel obstruction was graded as venous occlusion (complete flow interruption), severe obstruction (narrowing >90%), or mild-moderate obstruction (narrowing 50-90%). Severe venous obstruction/occlusion prevalence was 11.4% (n = 21) and was always asymptomatic. Collateral circulation was found in 80.9% of patients with severe obstruction/occlusion. Twelve patients (6.5%) had 3 leads. The rates of patients with secondary prevention of sudden cardiac death as indication for implantable devices and of those of patients with 3 leads were significantly greater in the group with severe obstruction/occlusion than in the non-severe obstruction/occlusion group (respectively, P = 0.004 and P = 0.03). Logistic analysis adjusted for venous thromboembolic risk factors confirmed that secondary prevention of sudden cardiac death as indication for implantable devices [odds ratio (OR), 7.1; 95% confidence interval (CI): 1.4-35.3; P = 0.017] and the presence of 3 leads (OR, 8.5; 95% CI: 1.75-41.35; P = 0.008) were predictors of severe obstruction/occlusion., Conclusion: In patients with implantable devices, severe venous obstruction prevalence is not negligible and the lack of symptoms does not exclude it. The presence of three leads and sudden cardiac death as indication for implantable devices seem to be associated with the presence of severe venous obstruction/occlusion., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.)

Background: In 2007, great concern arose regarding failure of implantable cardioverter defibrillator (ICD) leads from several manufacturers., Objective: Of this analysis was to evaluate the incidence and predictors of Sprint Fidelis lead failure in order to find the best clinical strategy to prevent lead-related adverse events., Methods: Four hundred fourteen patients (357 male, 67 ± 12 years) with ICD equipped with right ventricular Sprint Fidelis leads were followed up in our institution., Results: Over a median follow-up of 35 months (25th-75th percentile = 27-47 months) and a total follow-up of 1,231 patient-years, lead failures occurred in 40 of 414 (9.7%) patients. The annual rate was 3.2% per patient-year. Thirty-five (87.5%) failures were caused by pacing-sensing connector fracture. The risk of lead fracture was higher in patients younger than 70 years (odds ratio = 2.31; 95% confidence interval = 1.14-4.68, p = 0.02). Among 30 patients with pacing-sensing conductor failure and available device diagnostics for failure alerting, the diagnostic parameter which first responded to lead failure was the sensing integrity counter in 15 of 30 (50%), pacing impedance in 12 of 30 (40%), and non-sustained ventricular tachycardia in 3 of 30 (10%). The median time (25th-75th percentile) between diagnostics alert and lead failure-related adverse events or failure acknowledgment was 2.2 (0.3-13.0) days. Twenty-two patients suffered inappropriate shocks due to lead failure. In 50% of patients, daily monitoring by device diagnostics would have alerted physicians to impending lead failure at least 1 day in advance., Conclusions: Automatic algorithms based on device diagnostics may detect impending lead failure in nearly 50% of cases. Remote monitoring may prevent failure-related adverse events.

Aims: Evaluation of ambulatory blood pressure monitoring (ABPM), two-dimensional (2D) echo and clinical variables in predicting cardiac death and acute decompensated heart failure in patients with ischaemic cardiomyopathy and receiving a cardioverter-defibrillator implantation., Methods and Results: We studied 180 consecutive patients (169 men) on an out-patient basis, with systolic dysfunction (ejection fraction ≤35%) and previous myocardial infarction. All received a cardioverter defibrillator (ICD) (116 dual chamber, 36 monocameral and 28 biventricular), for primary prevention of sudden death and standard medical therapy for heart failure. Mean follow-up was 11.7 months. Two-dimensional echo was performed just before ICD implantation, ABPM and haematological samples 2 weeks later. Age, ejection fraction, creatinine, haemoglobin concentration, mean 24-h systolic blood pressure, mean 24-h diastolic blood pressure, mean 24-h heart rate, brain natriuretic peptide, QRS duration, % paced beats, ventricular scar, biventricular pacing, sex and diabetes were considered. Cox proportional hazards regression analysis was used to explore the relationship between events. ROC curves were built for each independent variable. Events occurred in 47 patients (26%); 7 deaths for refractory heart failure and 40 hospitalizations for acute decompensated heart failure. Low mean 24-h systolic blood pressure [hazard ratio 0.96, 95% confidence interval (CI) 0.93-0.99, P = 0.02], high creatinine (hazard ratio 1.61, 95% CI 1.06-2.47, P = 0.01), low haemoglobin concentration (hazard ratio 0.81, 95% CI 0.65-0.99, P = 0.04) and older age (hazard ratio 1.04, 95% CI 1.01-1.08, P = 0.02) were independent predictors of events., Conclusions: Ambulatory systolic blood pressure, haemoglobin, creatinine and age can stratify risk of death and acute decompensated heart failure in patients with ischaemic cardiomyopathy and ICD in whom 2D-echo ejection fraction is not predictive.

Cardiologists often are called to explain electrocardiograms of pacemaker/ implantable cardioverter (PMK/ICD) patients during arrhythmic events. The most frequent arrhythmia is atrial fibrillation (AF) whether in PMK or in ICD patients. Generally, it is not difficult to diagnose, it can affect the quality of life of this subgroup because it can generate inappropriate and painful therapies. Arrhythmias as atrioventricular block or other bradyarrhythmias can show a particular way of presentation specially for the device's intervention using specific algorithms that cardiologists should know to adequately interpret the phenomenon. For example, Rate Drop Response algorithm (to prevent syncope) or other antiarrhythmic functions for atrial tachyarrhythmias (Post Mode Switching Overdrive Pacing (PMOP) or Atrial Rate Stabilization) can alter surface electrocardiogram after AF or atrial ectopic beats. Ventricular arrhythmias in ICD patients are frequent. Burst, ramp and shock are therapies with a high percentage of efficacy. However, sometimes, supraventricular arrhythmias (SVT) can induce inappropriate interventions. In other cases appropriate burst, ramp or shock (during a ventricular tachycardia (VT)) can degenerate it in a fast ventricular tachycardia or in ventricular fibrillation with consequent shocks. Wavelet, onset, stability, and other algorithms, specifically in dual chamber ICDs, are used to discriminate SVT from VT assuring more specific interventions.