3D transvenous radiofrequency ablation of manifest epicardial posterior-septal accessory pathways in children: Can technology innovations improve the outcome?

AbstractIntroduction:The aim of the study was to revise our more recent experience about epicardial posterior-septal accessory pathways radiofrequency transcatheter ablation in children and young patients using a transvenous approach through the coronary sinus, to understand if new mapping and ablation technologies can increase success rate and safety.Methods and results:Twenty children (mean age 13 ± 3 years) with epicardial posterior-septal accessory pathways (14 in coronary sinus and 6 in the middle cardiac vein) underwent radiofrequency transcatheter ablation with CARTO-3® system with help of the CARTO-Univu® module. Acute success rate was 73%. No patient was lost to follow-up (mean time 11.4 ± 9 months). The recurrence rate was 19%. Two patients underwent a successful redo-procedure; the overall long-term success rate was 65%. Navistar® catheter presented the highest acute success rate in the coronary sinus. Navistar SmartTouch® was the only catheter that did not present recurrences after the acute success, and it was successfully used in two patients previously unsuccessfully treated with a Navistar ThermoCool®. Acute success rate was 79% without image integration with angio-CT, while it was 63% after the introduction of CARTO-Merge®.Conclusion:Epicardial posterior-septal accessory pathways can be definitively eliminated by transvenous radiofrequency transcatheter ablation in more than half of the cases in children. Acute success rate does not seem to depend on catheters used, but contact-force catheter seems to be useful in cases with recurrences. Image integration with cardiac-CT does not increase success rate, but it is useful to detect coronary sinus alterations to better guide ablation strategy

707 Transvenous radiofrequency ablation of epicardial posterior-septal accessory pathways in children with WPW syndrome: can technology and imaging innovations improve the outcome?

Abstract Aims The aim of the study was to analyse our recent single-centre experience about epicardial posterior-septal accessory pathways transcatheter ablation in children and young patients using radiofrequency through the coronary sinus, in order to understand which mapping and ablation strategy is associated with higher success rate and safety. Methods and results We reviewed all the cases of ablation of overt accessory pathways (in Wolff–Parkinson–White syndrome) with epicardial posterior-septal localization performed in children or young patients at our institution in the last 5 years. Twenty-two paediatric patients (mean age: 13 ± 3 years) with epicardial posterior-septal accessory pathways (15 in coronary sinus and 7 in the Middle Cardiac Vein) underwent radiofrequency transcatheter ablation with CARTO 3TM. Acute success rate was 77%. No patient was lost to follow-up (mean time 14.4 ± 9 months). The recurrence rate was 18%. Two patients underwent a successful redo-procedure; the overall long-term success rate was 68%. NAVISTAR® catheter presented the highest acute success rate in the coronary sinus. NAVISTAR SMARTTOUCH® was the only catheter that did not present recurrences after the acute success and it was successfully used in two patients previously unsuccessfully treated with a NAVISTAR THERMOCOOL®. Integration with angio-CT of coronary sinus branches obtained with CARTOMERGE was associated with higher success rate in patients with a previous failed ablation attempt. Conclusions Epicardial posterior-septal accessory pathways can be successfully treated with transvenous radiofrequency ablation in more than half of the cases in children/young patients. Acute success rate does not seem to depend on catheters used but contact-force catheter seems to be useful in cases with recurrences. Image integration with cardiac-CT reconstruction of coronary sinus branches anatomy can be useful to better guide ablation in case of previously failed attempts

Electroanatomic mapping-guided localization of alternative right ventricular septal pacing sites in children

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

Moderated poster - AVNRT cryoablation in children < 26 kg: efficacy and safety of electrophysiologically guided low voltage bridge strategy

Background and Aim: Recent studies have reported that the low voltage bridge (LVB) strategy is very effective in atrioventricular nodal reentrant tachycardia (AVNRT) ablation. The purpose of our study was to evaluate the efficacy and safety of AVNRT cryoablation in pediatric patients &lt; 26 Kg using the electrophysiologically guided LVB strategy both in the acute phase and in a mid-term follow up. Methods: Thirteen pediatric patients (69% males, mean age 7±1.65 years, mean weight 24.8±1.77 Kg), with previous history of AVNRT confirmed by the transesophageal atrial stimulation, underwent slow pathway cryoablation using the electrophysiologically guided LVB strategy. Results: In 12 patients a typical AVNRT was induced, while 1 patient showed both a typical and an atypical form. An AV “jump” occurred in 46% of patients. One small LVB was found in 7 patients (54%) at the M1-M2 level, in 4 (31%) at P2 or P2-M1 level, in 1(7.5%) at A2 and another 1 (7.5%) at M1 level. Acute success was 100% with an average of 5 cryoablations per patient. No peri-procedural complications occurred. All procedures were performed with near-zero fluoroscopy. No recurrence occurred during the follow up (10.58±10.23 months). Conclusion: AVNRT cryoablation using the electrophysiologically guided LVB strategy seems to be an effective and very safe procedure in small children who are the highest risk patients for this type of ablation

Physiological pacing in young patients with complex congenital heart defects

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/exercise stress demonstrated a physiological increase in the pacing rate with CLS, in synergy with spontaneous events. The accelerometer sensor histogram, during nonmovement stress, showed a “nonresponse” 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

CD4+CD28null T lymphocytes are expanded in young women with polycystic ovary syndrome

Women affected by polycystic ovary syndrome (PCOS) have an increased risk of cardiovascular disease. We demonstrated that women with PCOS showed an expansion of CD4+CD28null T cells, an aggressive population of T lymphocytes that has been recently associated with recurrent coronary instability and type 2 diabetes mellitus. This sheds new light on possible mechanisms responsible for the higher rate of cardiovascular disease among women with PCOS

Reversible atrial gap junction remodeling during hypoxia/reoxygenation and ischemia: a possible arrhythmogenic substrate for atrial fibrillation

Alteration of cardiomyocyte gap-junctions and component con nexins (Cx) has been suggested to contribute to the development of atrial fibrillation (AF), including postoperative AF We tested different possible stimuli, such as hypoxia and ischemia, influencing Cx43 and Cx40 expression and distribution in cultured atrial cells (HL-1) and reversibility of these processes after reoxygenation. Western-blot analysis and immunostaining using anti-Cx43, anti-Cx40 and anti-zonula occludens polyclonal antibodies were performed. HL-1 cells exposed to hypoxia for 24 and 48 h showed a reduction of Cx43 protein levels by 75% and 90% respectively (p < 0.001). During reoxygenation following 24 h of hypoxia, Cx43 levels increased to reach the basal level within 4811, while they remained at low level during reoxygenation following 48 h of hypoxia. Furthermore, atrial cardiomyocytes subjected to simulated ischemia (SI) were incubated in normoxic and hypoxic conditions for 3, 6, 9, 12 h. Atrial cardiomyocytes subjected to SI in addition to normoxia showed a progressive reduction of Cx43 levels beginning from 3 h. During SI and hypoxia, atrial Cx43 levels showed an initial decrease after 3 h with a subsequent rescue beginning from 6 h of exposure (p = 0.001). Hypoxia and ischemia per se downregulate Cx43 protein expression in atrial cardiomyocytes, but protein down regulation is reversible, depending on hypoxia duration and the association of the two triggers. These alterations characterize several conditions and might contribute to the generation of an arrhythmogenic substrate leading to AF onset and/or maintenance