Ian H. Law

PACES/HRS Expert Consensus Statement on the Management of the Asymptomatic Young Patient with a Wolff-Parkinson-White (WPW, Ventricular Preexcitation) Electrocardiographic Pattern

C PACES/HRS Expert Consensus Statement on the Management of the Asymptomatic Young Patient with a Wolff-Parkinson-White (WPW, Ventricular Preexcitation) Electrocardiographic Pattern Developed in partnership between the Pediatric and Congenital Electrophysiology Society (PACES) and the Heart Rhythm Society (HRS). Endorsed by the governing bodies of PACES, HRS, the American College of Cardiology Foundation (ACCF), the American Heart Association (AHA), the American Academy of Pediatrics (AAP), and the Canadian Heart Rhythm Society (CHRS)

Multi-Institutional Study of Implantable Defibrillator Lead Performance in Children and Young Adults Results of the Pediatric Lead Extractability and Survival Evaluation (PLEASE) Study

Background— Implantable cardioverter-defibrillator (ICD) therapy in children and congenital heart disease patients is hampered by poor long-term lead survival. Lead extraction is technically difficult and carries substantial morbidity. We sought to determine the outcomes of ICD leads in pediatric and congenital heart disease patients. Methods and Results— The Pediatric Lead Extractability and Survival Evaluation (PLEASE) is a 24-center international registry. Pediatric and congenital heart disease patients with ICD lead implantations from 2005 to 2010 were eligible. Study subjects comprised 878 ICD patients (44% congenital heart disease). Mean±SD age at implantation was 18.6±9.8 years. Of the 965 total leads, 54% were thin (⩽7F), of which 57% were Fidelis, and 23% were coated with expanded polytetrafluoroethylene. There were 139 ICD lead failures (14%) in 132 patients (15%) at a mean lead age of 2.0±1.4 years, causing shocks in 53 patients (40%). Independent predictors of lead failure included younger implantation age and Fidelis leads. Actuarial analysis showed an incremental risk of lead failure with younger age at implantation: <8 years compared with >18 years (P=0.015). The actuarial yearly failure rate was 2.3% for non-Fidelis and 9.1% for Fidelis leads. Extraction was performed on 143 leads (80% thin, 7% expanded polytetrafluoroethylene coated), with lead age as the only independent predictor for advanced extraction techniques. There were 6 major extraction complications (4%) but no procedural mortality. Conclusions— This study demonstrates that ICD leads in children and congenital heart disease patients have an age-related suboptimal performance, further compounded by a high failure rate of Fidelis leads. Advanced extraction techniques were common and correlated with older lead age. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00335036.Background— Implantable cardioverter-defibrillator (ICD) therapy in children and congenital heart disease patients is hampered by poor long-term lead survival. Lead extraction is technically difficult and carries substantial morbidity. We sought to determine the outcomes of ICD leads in pediatric and congenital heart disease patients.nnMethods and Results— The Pediatric Lead Extractability and Survival Evaluation (PLEASE) is a 24-center international registry. Pediatric and congenital heart disease patients with ICD lead implantations from 2005 to 2010 were eligible. Study subjects comprised 878 ICD patients (44% congenital heart disease). Mean±SD age at implantation was 18.6±9.8 years. Of the 965 total leads, 54% were thin (≤7F), of which 57% were Fidelis, and 23% were coated with expanded polytetrafluoroethylene. There were 139 ICD lead failures (14%) in 132 patients (15%) at a mean lead age of 2.0±1.4 years, causing shocks in 53 patients (40%). Independent predictors of lead failure included younger implantation age and Fidelis leads. Actuarial analysis showed an incremental risk of lead failure with younger age at implantation: 18 years ( P =0.015). The actuarial yearly failure rate was 2.3% for non-Fidelis and 9.1% for Fidelis leads. Extraction was performed on 143 leads (80% thin, 7% expanded polytetrafluoroethylene coated), with lead age as the only independent predictor for advanced extraction techniques. There were 6 major extraction complications (4%) but no procedural mortality.nnConclusions— This study demonstrates that ICD leads in children and congenital heart disease patients have an age-related suboptimal performance, further compounded by a high failure rate of Fidelis leads. Advanced extraction techniques were common and correlated with older lead age.nnClinical Trial Registration— URL: . Unique identifier: [NCT00335036][1].nn# Clinical Perspective {#article-title-15}nn [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00335036&atom=%2Fcirculationaha%2F127%2F24%2F2393.atom

Pediatric nonpost-operative junctional ectopic tachycardia medical management and interventional therapies.

OBJECTIVESnTo determine the outcomes of medical management, pacing, and catheter ablation for the treatment of nonpost-operative junctional ectopic tachycardia (JET) in a pediatric population.nnnBACKGROUNDnNonpost-operative JET is a rare tachyarrhythmia that is associated with a high rate of morbidity and mortality. Most reports of clinical outcomes were published before the routine use of amiodarone or ablation therapies.nnnMETHODSnThis is an international, multicenter retrospective outcome study of pediatric patients treated for nonpost-operative JET.nnnRESULTSnA total of 94 patients with JET and 5 patients with accelerated junctional rhythm (age 0.8 year, range fetus to 16 years) from 22 institutions were identified. JET patients presenting at age < or =6 months were more likely to have incessant JET and to have faster JET rates. Antiarrhythmic medications were utilized in a majority of JET patients (89%), and of those, amiodarone was the most commonly reported effective agent (60%). Radiofrequency ablation was conducted in 17 patients and cryoablation in 27, with comparable success rates (82% radiofrequency vs. 85% cryoablation, p = 1.0). Atrioventricular junction ablation was required in 3% and pacemaker implantation in 14%. There were 4 (4%) deaths, all in patients presenting at age < or =6 months.nnnCONCLUSIONSnPatients with nonpost-operative JET have a wide range of clinical presentations, with younger patients demonstrating higher morbidity and mortality. With current medical, ablative, and device therapies, the majority of patients have a good clinical outcome.

An international multicenter study comparing arrhythmia prevalence between the intracardiac lateral tunnel and the extracardiac conduit type of Fontan operations

OBJECTIVEnThe study objective was to determine whether the extracardiac conduit Fontan confers an arrhythmia advantage over the intracardiac lateral tunnel Fontan.nnnMETHODSnThis multicenter study of 1271 patients compared bradyarrhythmia (defined as need for pacing) and tachyarrhythmia (defined as needing antiarrhythmic therapy) between 602 patients undergoing the intracardiac Fontan and 669 patients undergoing the extracardiac Fontan. The median age at the time of the Fontan procedure was 2.1 years (interquartile range, 1.6-3.2 years) for the intracardiac group and 3.0 years (interquartile range, 2.4-3.9) for the extracardiac group (Pxa0<xa0.0001). The median follow-up was 9.2 years (interquartile range, 5-12.8) for the intracardiac group and 4.7 years (interquartile range, 2.8-7.7) for the extracardiac group (Pxa0<xa0.0001).nnnRESULTSnEarly postoperative (<30 days) bradyarrhythmia occurred in 24 patients (4%) in the intracardiac group and 73 patients (11%) in the extracardiac group (Pxa0<xa0.0001). Early postoperative (<30 days) tachyarrhythmia occurred in 32 patients (5%) in the intracardiac group and 53 patients (8%) in the extracardiac group (Pxa0=xa0not significant). Late (>30 days) bradyarrhythmia occurred in 105 patients (18%) in the intracardiac group and 63 patients (9%) in the extracardiac group (Pxa0<xa0.0001). Late (>30 days) tachyarrhythmia occurred in 58 patients (10%) in the intracardiac group and 23 patients (3%) in the extracardiac group (Pxa0<xa0.0001). By multivariate analysis factoring time since surgery, more patients in the extracardiac group had early bradycardia (odds ratio, 2.9; 95%xa0confidence interval, 1.8-4.6), with no difference in early tachycardia, late bradycardia, or late tachycardia.nnnCONCLUSIONSnOverall arrhythmia burden is similar between the 2 groups, but the extracardiac Fontan group had a higher incidence of early bradyarrhythmias. There was no difference in the incidence of late tachyarrhythmias over time between the 2 operations. Therefore, the type of Fontan performed should be based on factors other than an anticipated reduction in arrhythmia burden from the extracardiac conduit.

Fascicular and Nonfascicular Left Ventricular Tachycardias in the Young: An International Multicenter Study

The aim of this study was to evaluate the clinical presentation and outcomes of pediatric patients with ventricular tachycardia (VT) originating from left heart structures.

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 21xa0years 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 %) (pxa0<xa00.01). 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.

Nonfluoroscopic and Radiation-Limited Ablation of Ventricular Arrhythmias in Children and Young Adults: A Case Series

The purpose of this study was to report the feasibility and procedural technique of minimal or no fluoroscopy in the ablation of ventricular arrhythmias in the pediatric population. A retrospective review was performed of all patients <21xa0years old who underwent ablation of ventricular arrhythmias using three-dimensional (3D) mapping with no or minimal fluoroscopy at a single institution. Five patients underwent electrophysiology studies for ventricular tachycardia or frequent premature ventricular complexes. Three patients had right-sided arrhythmias, and two patients had left-sided arrhythmias. Electro-anatomic mapping with the 3D EnSite NavX system and radiofrequency ablation was used in all patients. No fluoroscopy was used in the patients with right-sided arrhythmias. The two patients with left-sided arrhythmias had 1.0 and 1.9xa0min of fluoroscopy, respectively. The mean procedure time was 168xa0min (range 95 to 270). There has been no recurrence at mean follow-up of >1xa0year. Three-dimensional mapping systems have allowed pediatric electrophysiologic procedures to be performed with minimal to no fluoroscopy in patients with challenging arrhythmias, including ventricular arrhythmias. The decrease in radiation exposure decreases the risk of long-term adverse sequelae resulting from radiation exposure, which is especially important in children.

Safety and Results of Cryoablation in Patients <5 Years Old and/or <15 Kilograms

Current recommendations discourage elective radiofrequency ablation in patients <5 years old and/or weighing <15 kg, primarily because of the greater complication rate. To describe the current use, complications, and immediate outcomes of cryoablation in this patient population, a multicenter retrospective review of all patients <5 years old and/or weighing <15 kg who were treated with cryoablation for arrhythmia was performed. Eleven centers contributed data for 68 procedures on 61 patients. Of those, 34% were elective and 24% (n = 16) were both cryoablation and radiofrequency ablation. The median age and weight at ablation was 3.5 years (range 8 days to 9.9 years) and 15.2 kg (range 2.3 to 23), respectively. Congenital heart disease was present in 23% of the patients. The immediate success rate of cryoablation alone was 74%. No major complications occurred with cryoablation only; however, 2 of the 16 patients who underwent cryoablation and radiofrequency ablation had major complications. Of the 50 patients receiving cryoablation, 8 (16%) had variable degrees of transient atrioventricular block. The recurrence rate was 20% after cryoablation and 30% after cryoablation plus radiofrequency ablation. In conclusion, cryoablation appears to have a high safety profile in these patients. Compared to older and larger patients, the efficacy of cryoablation in this small, young population was lower and the recurrence rates were higher. Cryoablations effect on the coronary arteries has not been fully elucidated and requires additional research.

Voltage Mapping for Slow-Pathway Visualization and Ablation of Atrioventricular Nodal Reentry Tachycardia in Pediatric and Young Adult Patients

Voltage guidance for the ablation of the slow pathway in atrioventricular nodal reentry tachycardia (AVNRT) is a dramatic shift from the traditional anatomy-guided approach within the triangle of Koch. The use of voltage gradient mapping has been evaluated in adults as an aid to identification of the slow pathway guiding placement of ablation applications. This study aimed to evaluate this technique of voltage-guided ablation of AVNRT in pediatric and young adult patients, who have a smaller, more compact triangle of Koch. A retrospective cohort study evaluated patients 20xa0years of age or younger with AVNRT who underwent voltage mapping. Using NavX, three-dimensional voltage maps of the right atrium were created during sinus rhythm, focusing primarily on the triangle of Koch. The voltage map gradients were adjusted to uncover a “voltage bridge” of lower voltage signals. This bridge was used as a surrogate of the slow pathway to guide cryoablation at this site. Of the 31 patients who underwent voltage mapping, three were excluded from the study due to inadequate mapping. All the patients experienced procedural success. In 86xa0% of the patients, there was an adequate voltage bridge to allow guided ablation. The successful ablation site was within the first three lesions for 60xa0% of the patients. Two patients experienced recurrence during a median follow-up period of 14xa0months. It appears that voltage-guided ablation of a voltage bridge in AVNRT can be used effectively and safely in the pediatric population.

The safety of modern anesthesia for children with long QT syndrome.

BACKGROUND:Patients with long QT syndrome (LQTS) may experience a clinical spectrum of symptoms, ranging from asymptomatic, through presyncope, syncope, and aborted cardiac arrest, to sudden cardiac death. Arrhythmias in LQTS are often precipitated by autonomic changes. This patient population is believed to be at high risk for perioperative arrhythmia, specifically torsades de pointes (TdP), although this perception is largely based on limited literature that predates current anesthetic drugs and standards of perioperative monitoring. We present the largest multicenter review to date of anesthetic management in children with LQTS. METHODS:We conducted a multicentered retrospective chart review of perioperative management of children with clinically diagnosed LQTS, aged 18 years or younger, who received general anesthesia (GA) between January 2005 and January 2010. Data from 8 institutions were collated in an anonymized database. RESULTS:One hundred three patients with LQTS underwent a total of 158 episodes of GA. The median (interquartile range) age and weight of the patients at the time of GA was 9 (3–15) years and 30.3 (15.4–54) kg, respectively. Surgery was LQTS-related in 81 (51%) GA episodes (including pacemaker, implantable cardioverter-defibrillator, and loop recorder insertions and revisions and lead extractions) and incidental in 77 (49%). &bgr;-blocker therapy was administered to 76% of patients on the day of surgery and 47% received sedative premedication. Nineteen percent of patients received total IV anesthesia, 30% received total inhaled anesthesia, and the remaining 51% received a combination. No patient received droperidol. There were 5 perioperative episodes of TdP, all in neonates or infants, all in surgery that was LQTS-related, and none of which was overtly attributable to anesthetic regimen. Thus the incidence (95% confidence interval) of perioperative TdP in incidental versus LQTS-related surgery was 0/77 (0%; 0%–5%) vs 5/81 (6.2%; 2%–14%). CONCLUSIONS:With optimized perioperative management, modern anesthesia for incidental surgery in patients with LQTS is safer than anecdotal case report literature might suggest. Our series suggests that the risk of perioperative TdP is concentrated in neonates and infants requiring urgent interventions after failed first-line management of LQTS.