Thomas Paul

Left Cardiac Sympathetic Denervation for Catecholaminergic Polymorphic Ventricular Tachycardia

Catecholaminergic polymorphic ventricular tachycardia is a potentially lethal disease characterized by adrenergically mediated ventricular arrhythmias manifested especially in children and teenagers. Beta-blockers are the cornerstone of therapy, but some patients do not have a complete response to this therapy and receive an implantable cardioverter-defibrillator (ICD). Given the nature of catecholaminergic polymorphic ventricular tachycardia, ICD shocks may trigger new arrhythmias, leading to the administration of multiple shocks. We describe the long-term efficacy of surgical left cardiac sympathetic denervation in three young adults with catecholaminergic polymorphic ventricular tachycardia, all of whom had symptoms before the procedure and were symptom-free afterward.

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)

Clinical Management of Catecholaminergic Polymorphic Ventricular Tachycardia The Role of Left Cardiac Sympathetic Denervation

Background— Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a genetic disorder causing life-threatening arrhythmias whenever sympathetic activity increases. &bgr;-&Bgr;lockers are the mainstay of therapy; when they fail, implantable cardioverter-defibrillators (ICDs) are used but often cause multiple shocks. Preliminary results with flecainide appear encouraging. We proposed left cardiac sympathetic denervation (LCSD) as useful additional therapy, but evidence remains anecdotal. Methods and Results— We report 63 patients with CPVT who underwent LCSD as secondary (n=54) or primary (n=9) prevention. The median post-LCSD follow-up was 37 months. The 9 asymptomatic patients remained free of major cardiac events. Of the 54 patients with prior major cardiac events either on (n=38) or off (n=16) optimal medical therapy, 13 (24%) had at least 1 recurrence: 0 patients had an aborted cardiac arrest, 2 patients had syncope only, 10 patients had ≥1 appropriate ICD discharges, and 1 patient died suddenly. The 1- and 2-year cumulative event-free survival rates were 87% and 81%. The percentage of patients with major cardiac events despite optimal medical therapy (n=38) was reduced from 100% to 32% (P<0.001) after LCSD, and among 29 patients with a presurgical ICD, the rate of shocks dropped by 93% from 3.6 to 0.6 shocks per person per year (P<0.001). Patients with an incomplete LCSD (n=7) were more likely to experience major cardiac events after LCSD (71% versus 17%; P<0.01) than those with a complete LCSD. Conclusions— LCSD is an effective antifibrillatory intervention for patients with CPVT. Whenever syncope occurs despite optimal medical therapy, LCSD could be considered the next step rather than an ICD and could complement ICDs in patients with recurrent shocks.Background— Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a genetic disorder causing life-threatening arrhythmias whenever sympathetic activity increases. β-Βlockers are the mainstay of therapy; when they fail, implantable cardioverter-defibrillators (ICDs) are used but often cause multiple shocks. Preliminary results with flecainide appear encouraging. We proposed left cardiac sympathetic denervation (LCSD) as useful additional therapy, but evidence remains anecdotal. Methods and Results— We report 63 patients with CPVT who underwent LCSD as secondary (n=54) or primary (n=9) prevention. The median post-LCSD follow-up was 37 months. The 9 asymptomatic patients remained free of major cardiac events. Of the 54 patients with prior major cardiac events either on (n=38) or off (n=16) optimal medical therapy, 13 (24%) had at least 1 recurrence: 0 patients had an aborted cardiac arrest, 2 patients had syncope only, 10 patients had ≥1 appropriate ICD discharges, and 1 patient died suddenly. The 1- and 2-year cumulative event-free survival rates were 87% and 81%. The percentage of patients with major cardiac events despite optimal medical therapy (n=38) was reduced from 100% to 32% ( P <0.001) after LCSD, and among 29 patients with a presurgical ICD, the rate of shocks dropped by 93% from 3.6 to 0.6 shocks per person per year ( P <0.001). Patients with an incomplete LCSD (n=7) were more likely to experience major cardiac events after LCSD (71% versus 17%; P <0.01) than those with a complete LCSD. Conclusions— LCSD is an effective antifibrillatory intervention for patients with CPVT. Whenever syncope occurs despite optimal medical therapy, LCSD could be considered the next step rather than an ICD and could complement ICDs in patients with recurrent shocks. # CLINICAL PERSPECTIVE {#article-title-34}

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

OBJECTIVES To determine the outcomes of medical management, pacing, and catheter ablation for the treatment of nonpost-operative junctional ectopic tachycardia (JET) in a pediatric population. BACKGROUND Nonpost-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. METHODS This is an international, multicenter retrospective outcome study of pediatric patients treated for nonpost-operative JET. RESULTS A 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. CONCLUSIONS Patients 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.

Incidence of coronary artery injury immediately after catheter ablation for supraventricular tachycardias in infants and children

BACKGROUND Several case reports have documented coronary artery stenosis or even occlusion after radiofrequency energy ablation (RFA) in children and adults. Coronary involvement early and late after RFA has also been described in animal models. OBJECTIVE The purpose of this study was to assess prospectively the incidence of coronary artery injury early after catheter ablation for supraventricular tachycardias (SVT) in children. METHODS From October 2002 to January 2008, 212 consecutive patients younger than 21 years with SVT underwent selective coronary angiography before and 30 minutes after RFA or cryoablation. RESULTS Median patient age was 12 years (range 0.3-20.4 years), and median body weight was 47 kg (range 5.5-130 kg). An accessory pathway was diagnosed in 112 patients, AV nodal reentrant tachycardia (AVNRT) in 84 patients, and both an accessory pathway and AVNRT in 16 patients. Congenital heart disease was present in 31 patients. In 2 of 117 patients who had RFA for an accessory pathway, an acute reduction in luminal diameter of the coronary artery adjacent to the ablation site was observed. These two patients with a structurally normal heart showed ST-segment changes with normalization of the ECG within 1 week. Both were clinically asymptomatic, and two-dimensional echocardiography documented normal ventricular function. Noninvasive testing did not reveal any evidence of persistent myocardial ischemia. No coronary artery damage was noted after ablation for AVNRT or after ablation with cryoenergy. CONCLUSION Coronary artery narrowing adjacent to the RFA site was noted in 2 of 117 patients with an accessory pathway and occurred only in patients with a posteroseptal pathway. Coronary angiography could be helpful in avoiding coronary lesions in these settings.

Left cardiac sympathetic denervation for the management of life-threatening ventricular tachyarrhythmias in young patients with catecholaminergic polymorphic ventricular tachycardia and long QT syndrome

BackgroundLeft cardiac sympathetic denervation (LCSD) may be a therapeutic adjunct for young patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) and long QT syndrome (LQTS) who are not fully protected by beta-blockade.ObjectiveThe objective of this analysis was to report our institutional experience with LSCD in young patients for the management of life-threatening ventricular arrhythmias in CPVT and LQTS.MethodsTen young patients with CPVT and LQTS underwent transaxillary LSCD at our institution. Mean age at surgery was 14.0 (range 3.9–42) years, mean body weight was 45.7 (range 15.5–90) kg. Five patients had the clinical diagnosis of CPVT, three were genotype positive for a mutation in the ryanodine-receptor-2-gene. Four of five LQTS patients were genotype positive. Indications for LCSD were recurrent syncope, symptomatic episodes of ventricular tachycardias and/or internal cardioverter–defibrillator (ICD) discharges, and aborted cardiac arrest despite high doses of beta-blockers.ResultsLCSD was performed via the transaxillary approach. No significant complications were observed. Two patients already had an ICD, 6 patients received an ICD at the same operation or shortly thereafter. Median length of follow-up after LCSD was 2.3 (range 0.6–3.9) years. After LCSD a marked reduction in arrhythmia burden and cardiac events was observed in all patients while medication was continued. None of the patients had any further ICD discharge for sustained VT.ConclusionsAfter LCSD, arrhythmia burden could significantly be reduced in all our young patients with CPVT and LQTS.

Biocompatibility screening in cardiovascular implants.

Zunehmendes Interesse gilt der Biokompatibilität kardiovaskulärer Implantate. Ziel dieser Arbeit ist die Vorstellung von Methoden und Ergebnissen der pathologischen Aufarbeitung von explantierten Implantaten. Die Standardeinbettung von Implantaten zur histologischen Beurteilung in Paraffin ist nur eingeschränkt geeignet, da metallische Anteile vor der Einbettung unter Beschädigung der Grenzfläche Gewebe/Implantat entfernt werden müssen. Alternativ kommt eine Einbettung in Kunstharze in Frage, wobei histologische Schnitte mittels Schneiden und Schleifen angefertigt werden. Dies ermöglicht die Untersuchung lokaler entzündlicher Vorgänge an der Oberfläche des Implantates. Zusätzlich interessieren bei der Aufarbeitung der Implantate die Reaktion und Struktur des umgebenden Gewebes sowie der benachbarten Grenzfläche zum Blutstrom. Neben der Histologie kommen immunhistochemische Verfahren sowie die Elektronenmikroskopie zum Einsatz. Unter Verwendung der genannten Methoden demonstrieren wir Befunde von Implantatpräparaten aus Tierversuchen und entsprechende Ergebnisse von Implantaten, die bei Patienten im Rahmen von Korrekturoperationen bei angeborenen Herzfehlern entfernt wurden. Nach der Implantation kommt es unabhängig vom Implantattyp zu einer raschen Re-Endothelialisierung der Gefäßoberfläche. In das nach Okkluder-Implantation initial gebildete Thrombusgewebe sprossen fibromuskuläre Zellen ein, wie sie auch nach Stentimplantation in der Intimahyperplasie gesehen werden. Entzündliche Reaktionen sind in Qualität und zeitlichem Verlauf materialabhängig. Mit einer vollständigen pathologischen Aufarbeitung kardiovaskulärer Implantate nach Explantation können Informationen über Einwachsen, Endothelialisierung und Entzündungsreaktionen gewonnen werden. Interest in information on biocompatibility of implants is increasing. The purpose of this paper is to discuss methods and results of pathological biocompatibility screening of explanted cardiovascular implants. Use of standard histology after embedding in paraffin is limited since metallic implants have to be removed during workup with disruption of the specimen. Alternatively, tissue blocks containing an implant can be embedded in methylmethacrylate or hydroxyethylmethacrylate and processed by sectioning with a diamond cutter and grinding, thus leaving the implant in situ and saving the tissue/implant interface for detection of local inflammatory reactions. Another important aspect of evaluation is the progress of thrombus organisation after initial fibrin clotting on the metal surface or in the inner part of occlusion devices. New methacrylate resins and embedding techniques allow for specific immunohisto-chemical staining of the specimen thus enabling characterisation of tissues surrounding the implant. Information on endothelialisation of the vascular surface of the implant can be obtained by means of immunohistochemistry or by scanning electron microscopy. Illustrating the use of these technologies, we demonstrate findings in tissue specimens from animal studies with different types of devices (i.e. stents, occlusion devices). We present corresponding findings in human specimens with implants that were removed during corrective surgery for congenital heart defects. Early endothelialisation of the vascular surface was seen after implantation in all types of devices. Cells within occlusion devices could be characterised histologically and immunohistochemically as fibromuscular cells as seen in intimal hyperplasia after stent implantation. Inflammatory implant-host reactions ranged from mild to moderate (medical grade stainless steel, nitinol) to severe (polytetrafluoroethylene [PTFE]). With an optimal work-up of cardiovascular implants, ingrowth and endothelialisation as well as inflammatory reactions in the surrounding tissue can be assessed. This information allows evaluation of individual tissue reactions to the implant and may serve as valuable basis for optimisation of biocompatibility by implant modification.

The diagnostic and therapeutic aspects of loss-of-function cardiac sodium channelopathies in children.

BACKGROUND Loss-of-function sodium channelopathies manifest as a spectrum of diseases including Brugada syndrome (BrS) and cardiac conduction disease. OBJECTIVE To analyze the diagnostic and therapeutic aspects of these disorders in children. METHODS Patients aged ≤ 16 years with genetically confirmed loss-of-function sodium channelopathies (SCN5A mutation), presenting with cardiac symptoms, positive family history, and/or abnormal electrocardiogram (ECG), were included. Abnormal ECG consisted of type 1 BrS ECG and/or prolonged conduction intervals (PR interval/QRS duration > 98th percentile for age). RESULTS Among the cohort (n = 33, age 6 ± 5 years, 58% male subjects, 30% probands), 14 (42%) patients were symptomatic, presenting with syncope (n = 5), palpitations (n = 1), supraventricular arrhythmias (n = 3), aborted cardiac arrest (n = 3), and sudden cardiac death (n = 2). Heart rate was 91 ± 26 beats/min, PR interval 168 ± 35 ms, QRS duration 112 ± 20 ms, and heart-rate corrected QT interval 409 ± 26 ms. Conduction intervals were prolonged in 28 (85%) patients; 6 of these patients also had spontaneous type 1 BrS ECG. Eight fever-associated events occurred in 6 patients; 2 of these were vaccination-related fever episodes. Treatment included aggressive antipyretics during fever in all patients; antiarrhythmic treatment included implantable cardioverter-defibrillator (n = 4), pacemaker (n = 2), and beta-blockers, either alone (n = 3) or in combination with device (n = 2). During follow-up (4 ± 4 years), 2 previously symptomatic patients had monomorphic ventricular tachycardia; there were no deaths. CONCLUSIONS Diagnosis of loss-of-function sodium channelopathies in children relies on cardiac symptoms, family history, and ECG. Fever and vaccination are potential arrhythmia triggers; conduction delay is the commonest finding on ECG. Beta-blockers have a role in preventing tachycardia-induced arrhythmias; implantable cardioverter-defibrillator should probably be reserved for severe cases.

Catheter ablation of idiopathic left and right ventricular tachycardias in the pediatric population using noncontact mapping

BACKGROUND Idiopathic ventricular tachycardia (VT) in children with a structurally normal heart can cause significant morbidity, and although rare, mortality. Conventional activation and pace mapping may be limited by nonsustained tachycardia or unstable hemodynamics. OBJECTIVE The aim of this study was to assess feasibility of catheter ablation of idiopathic VT in the pediatric population guided by noncontact mapping. METHODS Twenty consecutive pediatric patients with idiopathic VT underwent electrophysiologic study with the intention to use the noncontact mapping system EnSite 3000 (EnSite Array, St. Jude Medical Inc., Minneapolis, Minnesota). The multielectrode balloon array was introduced into the left or right ventricle, respectively, and tachycardia was analyzed using color-coded isopotential maps as well as reconstructed unipolar electrograms on the virtual geometry. The region of origin was identified in all of them, and the site of earliest activation with a QS pattern of the unipolar electrograms was guided for sites of ablation. RESULTS Idiopathic VT originated from the right ventricular outflow tract in 6 patients, from the left ventricle in 8, and from the aortic sinus cusp in 6 in this cohort with a median age of 14.4 (range: 4.8 to 20.9) years. Ablation was attempted in 18 of 20 children, and was acutely successful in 17 of these 18 (94%). During a mean follow-up of 2.3 +/- 1.7 years, VT recurred in 3, 2 of them have been treated with a second procedure, resulting in an overall intermediate-term success in 16 of 18 (89%) children with idiopathic VT. CONCLUSION Noncontact mapping can safely and effectively be used to map and guide catheter ablation of the tachycardia substrate of idiopathic VT in pediatric patients.

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.