Bubble bilevel ventilation facilitates gas exchange in anesthetized rabbits.

BACKGROUND: Bubble continuous positive airway pressure is an established therapy for infants in respiratory distress. In resource-limited settings, few treatment options exist for infants requiring further respiratory support. A bubble bilevel device has been developed to provide nonelectric, time-cycled, pressure-limited respiratory support. We compared the efficacy of bubble bilevel ventilation with conventional mechanical ventilation in sedated rabbits. METHODS: Six adult rabbits under inhaled isoflurane general anesthesia were ventilated by alternating intervals of conventional and bubble bilevel ventilation for three 10-15-min periods. During each period, interval arterial blood gas (ABG) measurements were obtained after at least 10 min on the respective mode of ventilation. RESULTS: The bubble bilevel system was able to deliver the following pressures: 20/7, 15/5, 12/5, 8/5 cm H2O. The estimated differences in arterial blood gas values on bubble bilevel vs. ventilator were as follows (normalized values): pH 7.41 vs. 7.40, pCO2 37.7 vs. 40, pO2 97.6 vs. 80. In addition, the bubble bilevel ventilation delivered consistent pressure waveforms without interruption for over 60 min on two rabbits. CONCLUSION: This study demonstrates promising in vivo results on the efficacy of a novel bubble bilevel device, which may prove useful for infants in respiratory distress. IMPACT: Given the lack of personnel, funds or infrastructure to provide neonatal mechanical ventilation in resource-limited settings, additional low-cost, low-tech treatments are necessary to save infant lives. Bubble bilevel ventilation reliably delivers two levels of airway pressure to anesthetized rabbits resulting in normalization of blood gases comparable to those achieved on a traditional ventilator. If proven effective, simple technologies like this device have the potential to significantly impact neonatal mortality due to respiratory distress globally.

Acute outcomes of three-dimensional mapping for fluoroscopy reduction in paediatric catheter ablation for supraventricular tachycardia.

BACKGROUND: Catheter ablation is a safe and effective therapy for the treatment of supraventricular tachycardia in children. Current improvements in technology have allowed progressive reduction in radiation exposure associated with the procedure. To assess the impact of three-dimensional mapping, we compared acute procedural results collected from the Catheter Ablation with Reduction or Elimination of Fluoroscopy registry to published results from the Prospective Assessment after Pediatric Cardiac Ablation study. METHODS: Inclusion and exclusion criteria from the Prospective Assessment after Pediatric Cardiac Ablation study were used as guidelines to select patient data from the Catheter Ablation with Reduction or Elimination of Fluoroscopy registry to compare acute procedural outcomes between cohorts. Outcomes assessed include procedural and fluoroscopy exposure times, success rates of procedure, and complications. RESULTS: In 786 ablation procedures, targeting 498 accessory pathways and 288 atrioventricular nodal reentrant tachycardia substrates, average procedural time (156.5 versus 206.7 minutes, p < 0.01), and fluoroscopy time (1.2 versus 38.3 minutes, p < 0.01) were significantly shorter in the study group. Success rates for the various substrates were similar except for manifest accessory pathways which had a significantly higher success rate in the study group (96.4% versus 93.0%, p < 0.01). Major complication rates were significantly lower in the study group (0.3% versus 1.6%, p < 0.01). CONCLUSIONS: In a large, multicentre study, three-dimensional systems show favourable improvements in clinical outcomes in children undergoing catheter ablation of supraventricular tachycardia compared to the traditional fluoroscopic approach. Further improvements are anticipated as technology advances.

Frequency of CIED remote monitoring: A quality improvement follow-up study.

BACKGROUND: Based on the findings of a prior study of CIED (Cardiac Implantable Electrical Device) remote monitoring (RM) frequency at the same center, the University of Michigan Congenital Heart Center (UMCHC) instituted a quality improvement (QI) change to reduce the frequency of routine CIED RM from every 2 months to every 3 months. The objective of this study is to determine the impact of this QI initiative to reduce workload without compromising patient care. METHODS: This is a single-center, retrospective cohort study of all UMCHC patients with CIEDs followed via Medtronic CareLink CIED remote monitoring system from July 2015 to June 2017, after the QI change in 2014. The primary outcome was success of transition to new monitoring schedule. Secondary outcomes included complications, incidence of actionable events (AES), patient compliance, and change in workload. Outcomes were compared to the prior study. RESULTS: There were 325 patients (mean age was 24  ±  14 years) included, of who 293 (90%) completely transitioned to the new RM schedule. During the study period, 96 transmissions included AES (4% of total), of which 50 (52%) were asymptomatic and discovered on routine monitoring. No patient experienced a complication attributable to decreased RM frequency. The mean number of interrogations decreased by 1.6 per patient over the 2-year period compared to prior study. CONCLUSIONS: This study demonstrated successful implementation of a QI initiative to reduce CIED monitoring frequency at a single center with no patient adverse events. The intervention reduced workload and potentially improved patient compliance with routine RM.

Variation in Pediatric Post-Ablation Care: A Survey of the Pediatric and Congenital Electrophysiology Society (PACES).

Although catheter ablation is a standard treatment for pediatric arrhythmias, there are no consensus guidelines for follow-up care. This study describes the variation in post-ablation practices identified through a survey of the pediatric and congenital electrophysiology society (PACES). Pediatric and congenital electrophysiology society members were invited to participate in an online survey of post-ablation practices in September 2014. Survey questions targeted routine post-ablation practices for three common arrhythmia substrates: atrioventricular nodal reentry tachycardia, concealed accessory pathways (AP), and manifest APs. Significant practice variation was defined as <90% concordance among respondents. There were 70 respondents from 67 centers, 29 (41%) in practice for <10 years. Uniform practices included aspirin after left side ablation by 65 (93%), immediate post-procedure ECG by 63 (90%), and performance of outpatient follow-up in 69 (99%) including ECG in 97-100% depending on substrate. The majority, 57 (81%), have standardized follow-up independent of substrate. Post-procedural observation is highly variable, with 25 (36%) discharging patients on the day of ablation, 22 (33%) observing patients in hospital overnight, and 21 (30%) basing hospitalization on pre-defined criteria. Immediate post-procedure echo is performed after all ablations in only 16 (23%). Discharge from outpatient care occurs at a median time of 12 months for each arrhythmia substrate. Common post-ablation practices are evident among pediatric electrophysiologists. However, they report significant variation in post-procedure monitoring practices and testing. The rationale for these variances, and their impact on costs and outcomes, should be defined.

Utility of intrathoracic impedance monitoring in pediatric and congenital heart disease.

BACKGROUND: The utility of cardiac device-based intrathoracic monitoring (OptiVol, Medtronic Inc., Minneapolis, MN, USA) for congestive heart failure (CHF) exacerbation has not been evaluated in pediatric or congenital heart disease patients. METHODS: This was a retrospective study of all patients at a single center with an endocardial OptiVol capable device. OptiVol index values were collected in 2-week bins from January 2007 to December 2010. The clinical outcomes were CHF exacerbation defined as hospitalization or medication change for CHF and device-treated ventricular arrhythmia based on remote or in-office device interrogation. Clinical and OptiVol data were collected by separate investigators blinded to the other parameter. OptiVol data were correlated to the clinical outcomes to determine sensitivity and predictability for multiple threshold values in the entire cohort and pediatric and congenital subgroups. RESULTS: Forty-seven patients were included. A total of 1,106 months of OptiVol data were collected. Median age of the cohort was 18 years (range 6-58 years). There were 23 pediatric, median age 13 years (range 6-16), at device implant, and 18 patients, median age 31 years (range 13-58), considered at risk for heart failure at implant. There were three heart failure exacerbations and 17 treated ventricular arrhythmias. The study population-specific positive predictive value (PPV) of OptiVol was low (sensitivity 33% and PPV ≤4.4%) for both CHF exacerbation and arrhythmias in all analyzed groups. CONCLUSIONS: The sensitivity and positive predictive value of intrathoracic impedance monitoring was low in this population of adult congenital and pediatric patients. Recent improvements to the OptiVol algorithm may decrease these deficiencies.

Verapamil in infants: an exaggerated fear?

The use of intravenous verapamil for tachyarrhythmia in infants is widely considered contraindicated due to the perceived risk of hemodynamic collapse after administration. This article reviews the relatively limited evidence that led to this well-known contraindication and highlights the interesting process by which medical practice may evolve in the absence of persuasive science.

Pattern of recovery for transient complete heart block after open heart surgery for congenital heart disease: duration alone predicts risk of late complete heart block.

Transient complete heart block (TCHB) is defined as complete interruption of atrioventricular conduction (AVC) after cardiac surgery followed by return of conduction. This study aimed to assess the risk for the development of late complete heart block (LCHB) after recovery of TCHB and to examine the electrocardiographic and electrophysiologic properties of the AVC system after TCHB. Of the 44 patients in this study who experienced TCHB, 37 recovered completely. Seven patients progressed from TCHB to intermittent CHB or LCHB requiring pacemaker implantation. Preoperative, early postoperative, and late postoperative electrocardiograms as well as postoperative atrial stimulation were obtained. The results showed that the median duration of TCHB was 5 days in the TCHB group compared with 9 days in the LCHB group (p = 0.01). All 37 subjects with TCHB recovered AVC within 12 days, but only two with LCHB did so (p = 0.02). The risk of LCHB for the patients with 7 days of postoperative TCHB or longer was 13 times greater than for the patients with fewer than 7 days of TCHB (p = 0.01). The median late postoperative PR interval was slightly but significantly longer in the LCHB group than in the TCHB group (p = 0.02). In contrast, the electrophysiologic properties between the two groups did not differ significantly. From those findings, we concluded that delayed recovery of AVC after surgical TCHB (≥7 days), but not electrophysiologic properties of recovered AVC assessed early in the postoperative period strongly, predicts risk of LCHB. Follow-up evaluation of AVC is particularly indicated for the delayed recovery group.

Implanted defibrillators in young hypertrophic cardiomyopathy patients: a multicenter study.

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease, with an annual risk of sudden cardiac death (SCD) estimated at 1 %. Limited data are available regarding both the risk of SCD in the young HCM population and the use of implantable cardioverter-defibrillators (ICDs). This retrospective study included all patients with HCM who underwent ICD implantation for primary or secondary prevention of SCD before the age of 30 years at five institutions between 1995 and 2009. There were 99 devices implanted in 73 patients. Appropriate shocks occurred for 11 % of all the patients. None of the previously identified conventional risk factors for SCD in HCM patients were associated with increased risk of appropriate shocks in the young study cohort. During a median follow-up period of 2.4 years, inappropriate shocks occurred for 22 % of the patients. Older age at implant was associated with a decreased risk of inappropriate shock. Those who underwent implantation in the earlier decade had a higher incidence of inappropriate shocks. Late complications including lead fracture or dislodgement, generator malfunction, and infection occurred for 32 % of the patients. Three patients died (4 %), one of whom had an arrhythmic sudden death. A greater proportion of primary prevention implantations was performed for patients from the latter decade. Over time, ICD use in young HCM patients has become increasingly primary prevention oriented. Shock rates mirror those reported in adult series, and there is a substantial incidence of device complications.

Novel ryanodine receptor 2 mutation associated with a severe phenotype of catecholaminergic polymorphic ventricular tachycardia.

An adolescent girl with a history of anxiety associated seizure-like episodes was ultimately diagnosed with catecholaminergic polymorphic ventricular tachycardia. She tested positive for a novel mutation of the ryanodine receptor. The report underscores how genetic arrhythmia syndromes may be mistaken for neurologic disorders.

Cryoablation therapy for atrioventricular nodal reentrant tachycardia in children: a multicenter experience of efficacy.

Atrioventricular nodal reentrant tachycardia (AVNRT), a common tachycardia in children, is routinely treated by catheter ablation using radiofrequency or cryothermal energy. Acute success rates of 95-97 % are reported for cryoablation, similar to those achieved with radiofrequency ablation (RFA). However, early studies reported higher recurrence rates after cryoablation for treatment of AVNRT than those reported for RFA. This study evaluated the success and recurrence rates for cryoablation in a current cohort of pediatric patients across several institutions. Patients 21 years old or younger with AVNRT who underwent cryoablation at five participating centers between 2004 and 2009 were retrospectively reviewed. Patient demographics and procedural data were extracted from patient records and analyzed. A total of 434 patients with AVNRT who underwent cryoablation were identified. Cryoablation was used as the exclusive ablation method for 379 patients. For 97 % (368/379) of these patients, cryoablation was acutely successful. A higher acute success rate was found with the 6-mm-tip catheter (99 %) than with the 4-mm-tip catheter (91 %) (p < 0.01). Recurrence was experienced by 7.3 % of the patients. Recurrence was more likely for those treated with the 4-mm-tip catheter (6/42, 14 %) than for those who had the larger catheters (12/204, 6 %) No patient experienced permanent heart block. Success and recurrence rates for this cohort of patients were similar to those reported for RFA used to treat AVNRT in pediatric patients. The findings show a higher success rate and a lower recurrence rate after cryoablation with a 6-mm-tip catheter than after use of the 4-mm-tip catheter, with an associated excellent safety profile.

Multicenter study of the effectiveness of implantable cardioverter defibrillators in children and young adults with heart disease.

Implantable cardioverter defibrillators (ICDs) are being used with increasing frequency in children and young adults. Our aim was to examine the appropriateness and frequency of ICD discharges in children and young adults, to compare the effectiveness of ICDs when placed for primary or secondary prevention, and to provide time-dependent analysis of ICD discharges. Data were collected from seven institutions on 210 patients <30 years of age who underwent ICD implantation from October 1992 to January 2007. Median age at implant was 15.4 years with a follow-up average of 3.3 years. Heart disease was categorized as electrical (n = 90, 42%), cardiomyopathic (n = 62, 30%), or congenital heart disease (n = 58, 28%). ICDs are increasingly placed for primary prevention. There are increased appropriate ICD discharges for ICDs placed for secondary prevention (52%) versus primary prevention (14%) at 5 years. There is no difference in the risk of inappropriate discharges between primary and secondary prevention indications. There is an increased risk for inappropriate therapy in the congenital heart disease population. An increasing number of ICDs are being placed for primary prevention in young patients, a marked shift in practice during the last two decades. The benefits of ICDs remain greater in secondary than in primary-prevention patients. In both groups, approximately 25% of patients received inappropriate discharges within 5 years of implant. Patients with congenital heart disease are the most affected by inappropriate discharges.

Inappropriate ICD discharges in single-chamber versus dual-chamber devices in the pediatric and young adult population.

BACKGROUND: Implantable cardioverter defibrillator (ICD) use is increasing in young patients and is frequently complicated by inappropriate device discharges (IDs), leading to discomfort, anxiety and, potentially, proarrhythmia. Dual-chamber (DC) ICDs may decrease IDs by improving rhythm discrimination, but are associated with increased size, expense, and implant complications. We examined whether the frequency of IDs was the same in dual- and single-chamber (SC) ICDs in young patients. METHODS: A multicenter review of patients

Sensitivity and specificity of an automated external defibrillator algorithm designed for pediatric patients.

OBJECTIVE: Electrocardiographic (ECG) rhythm analysis algorithms for cardiac rhythm analysis in automated external defibrillators (AEDs) have been tested against pediatric patient rhythms (patients < or = 8 years old) using adult ECG algorithm criteria. However these adult algorithms may fail to detect non-shockable pediatric tachycardias because they do not account for the difference in the rates of normal sinus rhythm and typical tachyarrhythmias in childhood. METHODS: This study was designed to define shockable and non-shockable rhythm detection criteria specific to pediatric patients to create a pediatric rhythm database of annotated rhythms, to develop a pediatric-based AED rhythm analysis algorithm, and to test the algorithm's accuracy. Pediatric rhythm detection criteria were defined for coarse ventricular fibrillation, rapid ventricular tachycardia, and non-shockable rhythms, including pediatric supraventricular tachycardia. Pediatric rhythms were collected as sustained, classifiable, rhythms > or = 9 s in length, and were annotated by pediatric electrophysiologists as clinically shockable or non-shockable based on pediatric criteria. Rhythms were placed into a pediatric rhythm database; each rhythm was converted to digitally accessible, public-domain, MIT rhythm data format. The database was used to evaluate a pediatric-based AED rhythm analysis algorithm. RESULTS: Electrocardiographic rhythms from 198 children were recorded. There were 120 shockable rhythms from 49 patients (sensitivity; coarse ventricular fibrillation: 42 rhythms, 100%; rapid ventricular tachycardia: 78 rhythms, 94%), for combined sensitivity of 96.0% (115/120). There were 585 non-shockable rhythms from 155 patients (specificity normal sinus: 208 rhythms, 100%; asystole: 29 rhythms, 100%; supraventricular tachycardia: 161 rhythms, 99%; other arrhythmias: 187 rhythms, 100%), for combined specificity of 99.7% (583/585). Overall accuracy for shockable and non-shockable rhythms was 99.0% (702/709). CONCLUSIONS: New pediatric rhythm detection criteria were defined and analysis based on these criteria demonstrated both high sensitivity (coarse ventricular fibrillation, rapid ventricular tachycardia) and high specificity (non-shockable rhythms, including supraventricular tachycardia). A pediatric-based AED can detect shockable rhythms correctly, making it safe and exceptionally effective for children.

Impact of a computer assisted navigation system on radiation exposure during pediatric ablation procedures.

BACKGROUND: During catheter ablation procedures, non-radiologic navigation systems may reduce fluoroscopic exposure and energy applications, as well as improve procedural success rates. OBJECTIVE: To examine the impact of a non-radiologic navigation system on ablation procedures in pediatric patients, the procedural characteristics and success rates prior to and following incorporation of the LocaLisa (LL) navigation system into a pediatric electrophysiology laboratory were compared. METHODS: Between January 2000 and April 2005, 246 consecutive patients underwent catheter ablation for either Atrioventricular Reentry Tachycardia AVRT (168) or Atrioventricular Nodal Reentry Tachycardia AVNRT (78). Ablation procedures performed prior to LL (108) were compared to ablation procedures performed using LL (113). The first 25 patients using LL were censored to remove the bias of a learning curve. RESULTS: There was no difference in demographic features between the two groups. Statistically significant decreases were found in the diagnostic (11.4 +/- 6.1 min v 18.8 +/- 9.8 min w/o LL), ablation (5.7 +/- 10.3 vs 18.5 +/- 20.1 min w/o LL) and total (17.2 +/- 12.6 vs 37.3 +/- 21.3 min w/o LL) fluoroscopy times for the LL group, as well as in the total number of energy applications (9.0 +/- 8.5 vs 12.3 +/- 12.2 w/o LL). Success rates were 99.1% w/ LL v 97.2% w/o LL (p = NS). No major complications were observed in either group. CONCLUSIONS: The use of a computer assisted navigation system significantly decreased the diagnostic, ablation, and total fluoroscopy times, as well as the number of energy applications, without affecting procedural success or complication rates. Non-radiologic navigation systems reduce radiation exposure during transcatheter electrophysiologic procedures and thus lower the lifetime radiation cumulative risk, a goal particularly important in children.

Transcatheter cryothermal ablation of junctional ectopic tachycardia in the normal heart.

BACKGROUND: Junctional ectopic tachycardia in the normal heart is rare and often is resistant to pharmacologic management. Transcatheter ablation using radiofrequency energy places the AV node at risk. OBJECTIVES: The purpose of this study was to report our experience with transcatheter cryothermal ablation using three-dimensional mapping in six patients with junctional ectopic tachycardia. METHODS: A review of clinical and electrophysiologic data was performed on all patients with structurally normal hearts who underwent cryothermal ablation for treatment of junctional ectopic tachycardia at two institutions. RESULTS: Six patients (age 7.7-36.5 years) underwent attempted transcatheter cryothermal ablation using three-dimensional mapping. Only one patient had achieved arrhythmia suppression on medical management. Cryothermal mapping (-30 degrees C) localized the junctional focus while normal conduction was monitored. The junctional focus was high in the triangle of Koch in four patients and was low in one patient. The sixth patient had only one run of junctional ectopic tachycardia during the procedure and therefore received an empiric cryoablation (-70 degrees C) lesion. Subsequent cryoablation lesions were delivered at and around the junctional focus. In one patient, cryomapping eliminated the junctional focus but resulted in transient complete AV block; therefore, cryoablation was not performed. All patients who received the cryoablation lesions had elimination of their junctional ectopic tachycardia at 6-week follow-up. The patient who did not receive a cryoablation lesion remained in a slower junctional rhythm at follow-up. CONCLUSION: Cryoablation of junctional ectopic tachycardia is safe and effective. Nonetheless, proximity to the His-Purkinje system may preclude success. Empiric cryoablation can be effective; cryotherapy may not yield immediate success, but a delayed salutary effect can follow.

Transcatheter cryotherapy for the treatment of supraventricular tachyarrhythmias in children: a single center experience.

INTRODUCTION: Transcatheter cryotherapy is an emerging technology for the treatment of children with supraventricular tachyarrhythmias. Limited data exist regarding the use of cryoablation therapy in children. We report a single center's experience with transcatheter cryoablation in the pediatric population. METHODS AND RESULTS: A retrospective review of demographic, procedural and outcome data was performed for patients undergoing cryoablation for treatment of supraventricular tachycardia (SVT). A historical control group was taken from the 3 years preceding the introduction of cryoablation. Between August 2003 and November 2005, 83 cryoablation procedures were performed in 81 patients (age: 4 to 21 years, mean: 13.4 years) for AV nodal reentrant tachycardia (AVNRT--53), AV reentrant tachycardia (AVRT--20), ectopic atrial tachycardia (EAT--9), and junctional ectopic tachycardia (JET--1). The acute success rate for all procedures was 88% (AVNRT: 96%, AVRT: 85%, EAT: 55%, and JET: 100%). Of 72 patients that underwent successful cryoablation, nine experienced recurrence of SVT (12.5%). The control group consisted of 73 patients (AVNRT--60, AVRT--13). There were no differences in demographic data between the two groups. The overall success rate for the RFA group (96%) was identical to that for patients with AVNRT and AVRT undergoing cryoablation. The recurrence rate for RFA (10%) was less but not significantly different than that for cryoablation (12%). There were no complications in either group. CONCLUSIONS: Cryoablation is a safe and effective alternative for the treatment of SVT in children.

Follow-Up of a Prospective Surgical Strategy to Prevent Intra-Atrial Reentrant Tachycardia After the Fontan Operation.

BACKGROUND: Intra-atrial reentrant tachycardia (IART) after the Fontan operation had an early reported incidence of 10% to 35% during early and intermediate follow-up and posed substantial management challenges. METHODS AND RESULTS: To reduce the incidence of IART after the Fontan procedure, we performed a randomized, double-blind study to evaluate the impact of an incision in the right atrium joining the lateral tunnel suture line and the tricuspid valve annulus. Between March 1998 and September 2003, 134 subjects (median age: 1.8 years; range: 1.3-5.2 years; 91 men) were randomly assigned to receive the incision. All 134 patients had a form of single ventricle pathological anatomy. The clinical course, electrocardiograms, and Holter monitoring were available for review in 114 subjects at a median of 8.2-year follow-up (range: 0.9-11.9 years). There were 2 late deaths, neither subject had IART. The combined incidence of sustained IART was 3.5% (4/114). There was no difference in the occurrence of sustained IART between those subjects receiving the incision and those who did not (2 in each group) during follow-up. No patients of either group experienced short-term complications. CONCLUSIONS: Despite the fact that the primary outcome of this trial was not reached, the most significant finding was that with current management, the incidence of IART is considerably lower than the early retrospective, observational studies suggested.

Patient and Procedural Correlates of Fluoroscopy Use During Catheter Ablation in the Pediatric and Congenital Electrophysiology Lab.

OBJECTIVE: To identify factors associated with fluoroscopy use in pediatric and congenital heart disease (CHD) patients. DESIGN: Retrospective cohort. SETTING: Pediatric electrophysiology lab in a single tertiary-care children's hospital. PATIENTS: Three hundred eighty-three patients who underwent electrophysiology study and ablation between January 2010 and December 2012. METHODS: Ablation procedures in which nonfluoroscopic navigation was employed were reviewed. Procedures using ≥ 10 minutes of fluoroscopy (high-fluoroscopy time; HF) were compared with those using <10 minutes (low-fluoroscopy time; LF). Group comparison of characteristics was made in the entire cohort and in CHD and anatomically normal heart subsets. RESULTS: During the study period, 416 ablation procedures were performed involving 471 substrates in 383 patients. Median fluoroscopy time was 6.7 minutes overall and 5.1 minutes with anatomically normal hearts. LF comprised 61% of all ablation and 69% of anatomically normal hearts. LF procedures were associated with anatomically normal hearts (93% vs. 63%; P < .0001). In anatomically normal hearts, HF was associated with accessory pathways (64% vs. 47%; P = .01), posteroseptal substrates (22% vs. 9%; P = .002), and ventricular substrates (12% vs. 1%; P < .0001). All cases of intra-atrial reentrant tachycardia were HF. HF was associated with trans-septal puncture (47% vs. 23%; P < .0001) though not when controlling for atrioventricular nodal reentrant tachycardia. LF was associated with cryoablation (56% vs. 17%; P < .0001). CONCLUSIONS: In pediatric and congenital EP, ablation procedures using cryoablation and in patients with anatomically normal hearts are associated with LF. In accessory pathway ablation, HF was not associated with trans-septal puncture.

Cardiac implantable electronic device remote monitoring surveillance in pediatric and congenital heart disease: Utility relative to frequency.

BACKGROUND: Heart Rhythm Society expert consensus provides recommendations for surveillance monitoring of cardiac implantable electronic devices (CIEDs), but limited data are available for the pediatric and congenital heart disease population. OBJECTIVE: The purpose of this study was to determine the rate of actionable events during CIED surveillance in this population, assess the utility of routine CIED remote monitoring, and assess the potential benefit from more frequent monitoring. METHODS: This was a retrospective cohort study of all CIED patients followed at a pediatric and congenital heart center and enrolled in the Medtronic Carelink system with either (1) a chronic (implanted for >6 months) CIED followed between July 1, 2010, and July 1, 2012, on a bimonthly schedule; or (2) a new CIED (implanted <6 months) between July 1, 2008, and July 1, 2012, followed on a monthly schedule. RESULTS: Aggregate mean age was 20 ± 13.7 years. There were 608 interrogations on newly implanted CIEDs with an actionable event rate of 11 per 100 patient-years. There were 2614 interrogations of chronic CIEDs with an actionable event rate of 22 per 100 patient-years. The odds of an actionable event on an asymptomatic remote monitoring transmission was lower than if symptomatic (odds ratio 0.04, 95% confidence interval 0.03-0.07). Tachyarrhythmia was the most common event. Predictors of actionable events were identified. CONCLUSION: In this population of pediatric and congenital heart disease patients, the rate of actionable events was low, especially on asymptomatic interrogations. Most actionable events were due to tachyarrhythmia. A more frequent than every 90-day monitoring schedule does not appear to be of significant benefit.

Antitachycardia pacemakers in congenital heart disease.

BACKGROUND: Many patients with congenital heart disease (CHD) acquire rhythm abnormalities related to their repair, most commonly intraatrial reentrant tachycardia (IART). Treatment of IART in CHD is often multifaceted, and may include medication, ablation, and pacing. Evidence regarding the use of antitachycardia pacing therapies is limited. OBJECTIVE: The aim of the study is to define the use and efficacy of antitachycardia pacing in patients with CHD at a single center. RESULTS: Eighty implants were performed on 72 patients between 2000 and 2010. Follow-up data of more than 3 months were available for 56 patients; median follow-up time was 2.8 years. Twenty (36%) patients received successful antitachycardia pacing at a median 1.3 years postimplant. For those patients with IART after implant, antitachycardia pacing was successful in 57%. Patients with two-ventricle repairs were more likely to have successful antitachycardia pacing than those with one-ventricle palliation (45% vs. 17%, P = .04). Patients with documented IART had more successful antitachycardia pacing than those with no documented atrial tachycardia prior to implant (46% vs. 7%, P = .006). Early complications of antitachycardia pacemaker implant occurred in six patients (11%); late complications after implant occurred in three patients (5.6%). Of the initial 72 patients implanted, there were six deaths (8%). CONCLUSIONS: Antitachycardia pacing therapies were successful in the majority of CHD patients who had IART after implant. Patients without documented atrial tachycardia prior to implant were unlikely to require or receive successful therapy from antitachycardia pacemaker. Those patients postatrial switch procedure who had documented IART prior to implant had the highest incidence of successful antitachycardia pacing therapies. Antitachycardia pacemaker implantation is an adjunct to the management of IART in CHD patients, but may not benefit patients who have not yet demonstrated IART.