Epidemiology of Postoperative Junctional Ectopic Tachycardia in Infants Undergoing Cardiac Surgery.

BACKGROUND: Junctional ectopic tachycardia (JET) complicates congenital heart surgery in 2% to 8.3% of cases. JET is associated with postoperative morbidity in single-center studies. We used the Pediatric Cardiac Critical Care Consortium data registry to provide a multicenter epidemiologic description of treated JET. METHODS: This is a retrospective study (February 2019-August 2022) of patients with treated JET. Inclusion criteria were (1) <12 months old at the index operation, and (2) treated for JET <72 hours after surgery. Diagnosis was defined by receiving treatment (pacing, cooling, and medications). A multilevel logistic regression analysis with hospital random effect identified JET risk factors. Impact of JET on outcomes was estimated by margins/attributable risk analysis using previous risk-adjustment models. RESULTS: Among 24,073 patients from 63 centers, 1436 (6.0%) were treated for JET with significant center variability (0% to 17.9%). Median time to onset was 3.4 hours, with 34% present on admission. Median duration was 2 days (interquartile range, 1-4 days). Tetralogy of Fallot, atrioventricular canal, and ventricular septal defect repair represented >50% of JET. Patient characteristics independently associated with JET included neonatal age, Asian race, cardiopulmonary bypass time, open sternum, and early postoperative inotropic agents. JET was associated with increased risk-adjusted durations of mechanical ventilation (incidence rate ratio, 1.6; 95% CI, 1.5-1.7) and intensive care unit length of stay (incidence rate ratio, 1.3; 95% CI, 1.2-1.3), but not mortality. CONCLUSIONS: JET is treated in 6% of patients with substantial center variability. JET contributes to increased use of postoperative resources. High center variability warrants further study to identify potential modifiable factors that could serve as targets for improvement efforts to ameliorate deleterious outcomes.

A Prospective Assessment of Optimal Mechanical Ventilation Parameters for Pediatric Catheter Ablation.

Catheter stability, an important factor in ablation success, is affected by ventilation. Optimal ventilation strategies for pediatric catheter ablation are not known. We hypothesized that small tidal volume and positive end-expiratory pressure are associated with reduced ablation catheter movement at annular positions. Subjects aged 5-25 years undergoing ablation for supraventricular tachycardia (SVT) or WPW at two centers from March 2015 to September 2016 were prospectively enrolled and randomized to receive mechanical ventilation with either positive end-expiratory pressure of 5 cm H2O (PEEP) or 0 cm H2O (ZEEP). Movement of the ablation catheter tip at standard annular positions was measured using 3D electroanatomic mapping systems under two conditions: small tidal volume (STV) (3-5 mL/kg) or large TV (LTV) (6-8 mL/kg). 58 subjects (mean age 13.8 years) were enrolled for a total of 266 separate observations of catheter movement. STV ventilation was associated with significantly reduced catheter movement, compared to LTV at all positions (right posteroseptal: 2.5 ± 1.4 vs. 5.2 ± 3.1 mm, p < 0.0001; right lateral: 2.7 ± 1.6 vs. 6.3 ± 3.5 mm, p < 0.0001; left lateral: 1.8 ± 1.0 vs. 4.3 ± 1.9 mm, p < 0.0001). The presence or absence of PEEP had no effect on catheter movement. In multivariable analysis, STV was associated with a 3.1-mm reduction in movement (95% CI 2.6-3.5, p < 0.0001), adjusting for end-expiratory pressure, annular location, and patient size. We conclude that STV ventilation is associated with reduced ablation catheter movement compared to a LTV strategy, independent of PEEP and annular position.

Assessment of a novel radiation reduction protocol for pediatric and adult congenital device implantation.

PURPOSE: Device implantation requires fluoroscopic guidance, which carries inherent risks of ionizing radiation. We evaluated the impact of a low-dose fluoroscopic protocol on radiation exposure during device implantation. METHODS: All patients who underwent pacemaker or ICD implantation with new transvenous leads from July 2011 to January 2018 were included. A novel ALARA protocol consisting of ultra-low frame rates (2-3 frames/s), low dose/frame (6-18 mGy/frame), and use of the "air-gap" technique in patients < 20 kg was employed. Demographics, procedural data, and radiation exposure levels were collected and analyzed. RESULTS: Thirty patients underwent device implantation without additional catheterization, electrophysiology study, or ablation procedure (median age 15 years; range 5-50) with a total of 43 leads placed. Forty-seven percent of patients had a primary rhythm disturbance, 33% had cardiomyopathy, and 20% had congenital heart disease. Fifty percent were pacemakers (53% dual-chamber, 27% ventricle, 20% atrial) and 50% of devices implanted were ICDs (87% single-chamber). All implants were acutely successful with acceptable atrial and ventricular sensing and capture thresholds. The median fluoroscopy time was 11.5 min (inter-quartile range (IQR) 8.0-18.2), median air kerma dose 4.0 mGy (IQR 2.5-19.5), and median dose-area product 27.8 µGy/m2 (IQR 17.1-106.5). Median implant procedure time was 133 min. One patient required revision secondary to device migration without lead derangement 2 days post-procedure. CONCLUSIONS: Use of a novel fluoroscopic protocol may help decrease radiation exposure to patients and staff without affecting efficacy or risk. These data may represent benchmarks against which future device implantation procedures can be compared.

Ultrasound-guided axillary venous access for pediatric and adult congenital lead implantation.

BACKGROUND: Axillary venous access with ultrasound guidance for pediatric transvenous lead implantation may reduce risks for pneumothorax and hemothorax. The objective was to retrospectively evaluate ultrasound-guided axillary vein access as an alternative to the subclavian approach. METHODS: The technique consists of ultrasonographic identification of the axillary vein at the deltopectoral groove after initial contrast venography. A micropuncture kit is used for initial ultrasound-guided percutaneous access with fluoroscopic confirmation of wire position. Pocket creation is performed, and sheath insertion and lead implantation proceed as usual. Demographic, procedural, and radiation exposure data were collected and analyzed. RESULTS: Sixteen patients (median age = 13 years, 8-50 years; median weight = 56 kg, 29-77 kg) underwent lead implantation; two additional patients required fluoroscopy due to poor acoustic windows (89% success). Fifteen of 21 leads (71%) were ventricular; 50% of implants were pacemakers, and 31% were dual chamber. Median time to venous access was 13 min (interquartile range (IQR) = 9.25-20.25) and median implant procedure time was 156 min (IQR = 112-172). Median fluoroscopy time was 18.0 min (IQR = 11.9-29.6), median air kerma was 9.0 mGy (IQR = 3.0-28.5), and median dose-area product was 30.2 Gy-cm2 (IQR = 16.1-234.5). One patient required generator pocket revision 2 days postprocedure without lead dislodgement. There were no other complications encountered. CONCLUSIONS: Transvenous pacemaker and implantable cardioverter-defibrillator lead implantation in the pediatric and adult congenital population through ultrasound-guided axillary venous access is safe and efficacious. This technique may provide a low-risk alternative for vascular access for pediatric implantation procedures.

The "hidden" concealed left-sided accessory pathway: An uncommon cause of SVT in young people.

BACKGROUND: Concealed left-sided accessory pathways (CLAP) are a cause of supraventricular tachycardia (SVT) in the young. Most are mapped with right ventricular (RV) apical/outflow pacing. Rarely, alternative means of mapping are required. We review our experience from three pediatric electrophysiology (EP) centers with a rare form of "hidden" CLAP. METHODS: All patients <21 years undergoing EP study from 2008 to 2014 with a "hidden" CLAP (defined as an accessory pathway [AP] for which RV pacing at cycle lengths [CL] stable for mapping did not demonstrate eccentric retrograde conduction) were included. EXCLUSION CRITERIA: preexcitation. Demographic, procedural, and follow-up data were collected. RESULTS: A total of 23 patients met the criteria (median age, 14.3 years [range 7-21], weight, 51 kg [31-99]). 21 (96%) had SVT and one AFIB (4%). APs were adenosine sensitive in 7/20 patients (35%) and VA conduction was decremental in six (26%). CLAP conduction was demonstrable with orthodromic reentrant tachycardia in all patients, with RV extrastimulus testing in seven (30%) and with rapid RV pacing (

Tricking CARTO: Cryoablation of Supraventricular Tachycardia in Children with Minimal Radiation Exposure Using the CARTO3 System.

BACKGROUND: CARTO3 is frequently used during ablation but is not designed to allow visualization of non-CARTO3 ablation catheters. We describe how cryoablation catheters can be visualized and recorded using CARTO3 with minimal fluoroscopy (FLUORO) usage. METHODS: Retrospective review of patients ≤21 years undergoing cryoablation with CARTO3 from 2010 to 2013 for ablation of supraventricular tachycardia. After mapping with a Navistar catheter, the Navistar was removed and a cryocatheter was utilized. The cryocatheter was connected to the pin box via a jumper cable and the pin box was connected to the CARTO3 patient interface unit. Locations of ablation attempts with the cryocatheter were recorded with the "Create Snapshot" tool. Clinical characteristics and radiation doses were compared between patients undergoing cryoablation (cryoenergy [CRYO]) to an age- and diagnosis-matched control group (CONTROL) undergoing RF ablation. RESULTS: A total of 174 ablations were performed and 14 patients underwent cryoablation (CRYO, 13.3 ± 4.7 years, weight 42 ± 14 kg). Indications for cryoablation were: five atrioventricular nodal reentry tachycardia (36%), four ectopic atrial tachycardia (29%), three concealed accessory pathways (21%), and two Wolff-Parkinson-White syndromes (14%). Acute success was achieved in all patients (100%) with no complications and one recurrence (7%). The site of successful cryoablation was successfully recorded on the CARTO3 system in all cases. Radiation doses were low and not different from an age-, era-, and diagnosis-matched control group undergoing RF ablation (CRYO 3.2 ± 0.8 mGy vs CONTROL 1.6 ± 0.4 mGy, P = 0.07). CONCLUSIONS: Though a "closed" system, CARTO3 can be "tricked" to allow for the use of cryoablation, allowing clear catheter visualization, mapping, and recording of ablation lesions with minimal FLUORO usage.