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The article describes the case of a male patient with dextro-transposition of great arteries previously treated with palliative Mustard procedure and underwent transvenous implantation of dual-chamber pacemaker (PM). A subcutaneous cardioverter defibrillator was implanted to prevent sudden death in accordance with the current guidelines. He was admitted to the hospital in August 2014 after five shocks delivered during a treadmill workout and a diagnosis of inappropriate therapies was made.

Background: The stretching of the lead caused by somatic growth may lead to complications (dislodgement, fracture, failure) of transvenous leads implanted in pediatric patients. Atrial loop and absorbable ligatures may prevent it. Periodical lead advancement with lead pushing from the pocket may be an option to growth‐induced stretching. Our aim was to analyze retrospectively the outcome of periodical transvenous lead advancement in children with pacemaker (PM). Methods: A procedure of lead advancement was performed in patients with a single‐chamber PM implanted for isolated congenital complete atrioventricular block or sinus node dysfunction with growth‐induced lead straightening/stretching. The PM pocket was opened, the lead was released from subcutaneous adherences and was gently advanced to shape again a loop/semi‐loop in the atrium without dislodging the tip. Lead data (threshold, sensing, impedance) were compared before and after the procedure. Data are described as median (25th–75th centiles). Results: 14 patients with 13 VVIR and 1 AAIR PM implanted at 6.8 (5.9–8.0) years of age, 23 (19–26) kg, 118 (108–124) cm, underwent 30 advancement procedures, 1.5 (1.0–2.3) per patient, during follow‐up [45 (35–63) months]. Delta between procedures was: 18 (14–25) months, 11 (7–13) cm, 6 (4–9) kg; 90% of leads were successfully advanced without complications. Three unsuccessful procedures occurred with longer times [30 (14–37) months]. Electrical lead parameters did not show significant differences pre‐/post‐procedures. Conclusion: the advancement of transvenous leads in children seems safe and effective. This procedure may be another possible choice to preserve transvenous lead position and function until growth has completed. [ABSTRACT FROM AUTHOR]

Background: Small retrospective studies reported that left ventricular (LV) pacing is likely to preserve LV function in children with isolated congenital complete atrioventricular block (CCAVB). The aim of this study was to prospectively evaluate LV contractility and synchrony in a cohort of neonates/infants at pacemaker implantation and follow‐up. Methods: Patients with CCAVB who underwent LV pacing were evaluated with electrocardiogram and echocardiogram in a single‐center, prospective study. Data were collected at implantation, at 1‐month and every year of follow‐up, up to 5 years. LV ventricular dimensions (diameters and volumes), systolic function (ejection fraction [EF] and global longitudinal strain [GLS]), and synchrony were evaluated. Data are reported as median (25th‐75th centiles). Results: Twenty consecutive patients with CCAVB underwent pacemaker implantation (12 single‐chamber pacemaker [VVIR] and eight dual‐chamber pacemaker [DDD]) with epicardial leads: 17 on the LV apex and three on the free wall. Age at implantation was 0.3 months (1 day‐4.5 months). Patients showed good clinical status, normal LV dimensions, preserved systolic function, and synchrony at 60 (30‐60) months follow‐up. EF increased to normal values in patients with preimplantation EF <50%. Presence of antibodies and pacing mode (DDD vs VVIR) had no impact on the outcome. Conclusions: LV pacing preserved LV systolic function and synchrony in neonates and infants with CCAVB at 5‐year follow‐up. LV EF improved in patients with low preimplantation EF. Pacing mode or the presence of autoantibodies did not demonstrated an impact on LV contractility and synchrony. [ABSTRACT FROM AUTHOR]

Arrhythmogenic cardiomyopathy (ACM) is a very rare condition among pediatric patients. Sudden cardiac death (SCD) is the main complication and often requires ICD implantation. Aim of the study is the evaluation of the outcomes of ICD implanted ACM pediatric patients in terms of safety, efficacy and complications. All pediatric patients (<18 y.o.) diagnosed with ACM and who were implanted with ICD since 2009 in Our Institution were collected. Implantation was decided according to current recommendations/ guidelines, and outcome was recorded during follow-up. Nineteen consecutive ACM patients were implanted with ICD. Subcutaneous ICDs (S-ICD) were implanted in 15 patients (79%) while transvenous ICDs (TV-ICD) in 4 patients (21%). Mean age at implantation was 14.3 ± 2.1 y.o. ICDs were implanted for secondary prevention in 4 (21%) patients, and for primary prevention in 15 (79%). During the follow-up (5.59 ± 3.4 years), appropriate ICD interventions were delivered in 4 (21%) patients for sustained VTs, [2 implanted in primary prevention (13%) and 2 in secondary prevention (50%)]. No defibrillation failures occurred. Inappropriate shocks occurred in 2 cases (10.5%). Device-related complications requiring device revision occurred in 3 (16%): lead dislodgement, surgical skin erosion and sensing defect. In a pediatric ACM cohort, appropriate ICD therapies occurred in a minority of primary prevention patients and frequently in secondary prevention patients. The rate of inappropriate shocks and device-related complications were even more rare and mostly wound related. Therefore, ICD therapy in pediatric ACM is effective and safe. • Arrhythmic risk stratification is challenging in ACM pediatric patients. • Outcome of ICDs in ACM pediatric patients has never been described before. • The choise of ICD to implant is challenging in ACM pediatric patients. [ABSTRACT FROM AUTHOR]

Abstract: Background: Alternative right ventricular (RV) sites (RVAPS) have been proposed to prevent or reduce RV pacing‐induced left‐ventricular (LV) dysfunction. Nonfluoroscopic 3D electroanatomic mapping systems (EAM) have been developed to guide cardiac catheter navigation and reduce fluoroscopy during electrophysiological procedures or pacemaker implantations. Aim: The aim of the study was to compare the results of EAM‐guided permanent pacemaker implantation aiming at RVAPS with conventional fluoroscopic‐guided implantation in RV apex (RVA) in children and adolescents. Methods: A prospective, randomized analysis was performed on children/adolescents with complete atrioventricular block (CAVB) who underwent EAM‐guided pacemaker and transvenous leads implantation into RVAPS (EAM‐RVAPS) or conventional, fluoroscopic‐guided implantation into RV apex (RVA). In EAM‐RVAPS, a pacing map guided the implantation of ventricular leads in septal sites with narrower QRS. After implantation, LV contractility (ejection fraction [EF], Global Longitudinal Strain [GLS]) and synchrony were evaluated at 1–12 months. Results: Twenty‐one pediatric patients with CAVB, with (six patients) or without structural heart diseases, aged 4–16 (median 10.5) years, were divided in two groups: EAM‐RVAPS (11 patients, four dual‐chamber/DDD, seven single‐chamber/VVIR pacemakers) and RVA (10 patients, one DDD/nine VVIR). The two groups did not show significant differences for preoperative parameters. EAM‐RVAPS showed: preserved LVEF and synchrony (not significantly different than RVA), significantly lower GLS and radiation doses/exposures, in spite more complex procedures, significantly longer procedure times and narrower paced QRS than RVA. Conclusions: EAM‐guided procedures have been useful to reduce radiation exposure and to localize RVAPS with narrower paced QRS and lower GLS than RVA. [ABSTRACT FROM AUTHOR]

Aim: Young patients with operated complex congenital heart defects (CHD) often develop sinus node dysfunction (SND) requiring permanent pacing with rate-responsive function. Activity-driven sensors cannot account for nonmovement stress and cannot modulate heart rate physiologically. Closed Loop Stimulation (CLS, Biotronik, Berlin, Germany) is a physiological rate-responsive pacemaker based on the indirect measure of ventricular contractility. No data are available on the effects of such pacing strategy in young patients.Methods: We report a series of nine patients with CHD and SND who underwent single-chamber CLS-atrial pacing with endocardial or epicardial lead. During the first 30 days, the pacemaker was programmed in AAI pacing mode and then was switched to CLS-atrial pacing mode. An in-hospital control was scheduled 1–2 months later to evaluate the CLS response to neurovegetative stresses (i.e.,nonmovement stress [Stroop color test, handgrip] and exercise stress test) and Holter monitor. CLS pacing was compared with rate-responsive accelerometer-driven pacing (AAIR).Results: At telemetric interrogation, CLS pacing showed a more physiological pattern of 24-h heart rate trends than accelerometer sensors. The data obtained during nonmovement/exercisestress demonstrated a physiological increase in the pacing rate with CLS, in synergy with spontaneous events. The accelerometer sensor histogram, during nonmovement stress, showed a “non-response" behavior (only lower rate events), and during exercise test showed most events in lower rate range. Holter monitoring showed increase of average and maximum heart rate compared with AAIR.Conclusion: In young CHD patients, endocardial/epicardial CLS-atrial pacing demonstrated a physiological response of heart rate to neurovegetative and physical stresses. [ABSTRACT FROM AUTHOR]

Aims Right ventricular (RV) apical (RVA) pacing can induce left ventricular (LV) dyssynchrony, remodeling, and dysfunction in children with complete atrioventricular block (CAVB). We compared the functional outcome of RVA with RV alternative pacing sites (RVAPS), including para-Hisian, septal, and outflow tract sites. Methods This is a single-center, retrospective study. Data were collected before pacemaker implantation (transvenous leads), postoperatively, at 6 months, and at 1-2-3-4 years. Electrocardiogram evaluation included QRS duration, axis, QTc/JTc, and QTc dispersion. Echocardiographic evaluation included 2-D/3-D assessment of ventricular dimensions (Z-score of LV end-diastolic dimension), function (ejection fraction), and synchrony. Results From 2009 to 2015, 55 patients with CAVB, aged 3-17 years, with or without other congenital heart defects, underwent RVAPS (30 patients, median age 11 years) or RVA (25 patients, median 12 years). All leads were positioned into the septum. Before implantation, no significant differences in parameters were observed, except for higher Z-score in RVAPS than in RVA. After implantation, at a median follow-up of 2.5 (range 1-6) years, the two groups showed no significant differences in LV dimensions, contractility, and synchrony. QRS intervals of RVAPS were significantly shorter than RVA. Clinical status was good and contractility/synchrony indexes were normal or adequate in all patients. Conclusions In pediatric patients, RVAPS and RVA showed no significant differences in LV dimensions, contractility, and synchrony. Preimplantation dilated patients showed LV reverse remodeling. RVAPS demonstrated shorter QRS intervals. Therefore, septal pacing sites, either RVA or RVAPS, seem to determine good contractility and synchrony at a mid-term follow-up. [ABSTRACT FROM AUTHOR]

Background Transcatheter cryoablation is a well-established technique for the treatment of atrioventricular nodal reentry tachycardia (AVNRT) in children. Nevertheless, atrioventricular nodal slow-pathway conduction may recur after an acutely successful procedure. The aim of this study was to evaluate the long-term outcome of acutely successful AVNRT cryoablations in pediatric patients in case of focal cryolesion and in case of need for High-Density Linear Lesion (HDLL) cryoablation due to focal failure. Methods Sixty-nine consecutive pediatric patients (30 males, mean age 12.4 ± 3.2 years; range: 5.4-18.0 years) underwent 3D-guided cryoablation for AVNRT at our institution from July 2013 to November 2014. When a focal cryoablation was acutely unsuccessful, a 3D-guided HDLL was created delivering multiple overlapping cryolesions/cryoenergy applications from the ventricular side of the tricuspid annulus to the atrial side, including the site of focal cryoablation if transiently successful. Results No permanent cryoablation-related complications occurred. Acute success rate was 98.5% (68 out of 69): in 55.9% (38 out of 68) with focal-lesion and in 44.1% (30 out of 68) with HDLL. Mean follow-up was 25.3 months and AVNRT recurrence rate was 13.2% (nine out of 68): 5.2% (two out of 38) with focal lesion and 23.3% (seven out of 30) with HDLL (P = 0.036). Conclusions In cryoablation of AVNRT in children, the need for a more aggressive protocol (HDLL), due to the failure of focal ablation, is strictly related to higher recurrence rates. Indeed, AVNRT recurrences after cryoablation in children seem to be due to a larger and deeper substrate rather than due to the type of energy used. [ABSTRACT FROM AUTHOR]