Mathias Emmel

C3 deposition glomerulopathy due to a functional Factor H defect

Factor H defect Sandra Habbig, Michael J. Mihatsch, Stefan Heinen, Bodo Beck, Mathias Emmel, Christine Skerka, Michael Kirschfink, Bernd Hoppe, Peter F. Zipfel and Christoph Licht Division of Pediatric Nephrology, Children’s Hospital of the University of Cologne, Cologne, Germany; Institute of Pathology, Basel, Switzerland; Leibniz Institute for Natural Products Research and Infection Biology, Jena, Germany; Department of Pediatric Cardiology, Children’s Hospital of the University of Cologne, Cologne, Germany; Institute of Immunology, University of Heidelberg, Heidelberg, Germany; Friedrich Schiller University, Jena, Germany; Division of Pediatric Nephrology, The Hospital for Sick Children; University of Toronto, Toronto, Ontario, Canada

Ventricular preexcitation associated with dilated cardiomyopathy: a causal relationship?

Over a six year period, we identified four children with dilated cardiomyopathy associated with ventricular preexcitation, three in the absence of any documented tachyarrhythmias, and one with but a solitary episode of tachyarrhythmia. None of them had another identifiable aetiology for the cardiomyopathy. Based on the 12 lead electrocardiogram, and/or invasive electrophysiologic studies, we localised the accessory pathways to the right atrioventricular groove in all patients. We commenced antifailure medications in two of the four patients, but did not produce any measurable improvement in ventricular function. Catheter ablation was performed in two patients, with resolution of the cardiomyopathy. The ventricular preexcitation disappeared spontaneously in one child during follow-up, again with resolution of cardiomyopathy. The youngest patient continues to receive antifailure medications, albeit without improvement. We suggest, therefore, that dilated cardiomyopathy of reversible nature is associated with manifest ventricular preexcitation, even in the absence of sustained arrhythmias.

Dilated cardiomyopathy in children with ventricular preexcitation: the location of the accessory pathway is predictive of this association.

BACKGROUND Ventricular preexcitation may be associated with dilated cardiomyopathy, even in the absence of recurrent and incessant tachycardia. METHODS This report describes the clinical and electrophysiologic characteristics of 10 consecutive children (6 males), with median age of 8 years (range, 1-17 years), who presented with dilated cardiomyopathy and overt ventricular preexcitation on the 12-lead electrocardiogram. Incessant tachycardia as the cause of dilated cardiomyopathy could be excluded. Coronary angiography, right ventricular endomyocardial biopsy (4/10 patients), and metabolic and microbiologic screening were nondiagnostic. RESULTS The electrocardiograms suggested right-sided pathways in all patients. A right-sided accessory pathway was demonstrated in 8 patients during invasive electrophysiologic study (superoparaseptal, n = 5; septal, n = 2; fasciculoventricular, n = 1). All pathways were successfully ablated (radiofrequency ablation in 7, cryoablation in 1). Two patients had spontaneous loss of ventricular preexcitation during follow-up. Left ventricular (LV) function completely recovered after a loss of preexcitation in all patients. CONCLUSIONS Right-sided accessory pathways with overt ventricular preexcitation and LV dyssynchrony may cause dilated cardiomyopathy. An association between such pathways and dilated cardiomyopathy is suggested by the rapid normalization of ventricular function and reverse LV remodeling after a loss of ventricular preexcitation.

Percutaneous Radiofrequency Septal Reduction for Hypertrophic Obstructive Cardiomyopathy in Children

OBJECTIVES The aim of this study was to assess the efficacy of radiofrequency catheter ablation (RFCA) in the treatment of hypertrophic obstructive cardiomyopathy in children. BACKGROUND Hypertrophic obstructive cardiomyopathy is an uncommon cause of left ventricular outflow tract obstruction in children. In symptomatic patients, open heart surgical myectomy has hitherto been the only therapeutic option. METHODS In 32 children, at a median age of 11.1 (range 2.9 to 17.5) years and weight of 31 (15 to 68) kg, ablation of the hypertrophied septum was performed using a cool-tip ablation catheter via a femoral arterial approach. The median number of lesions was 27 (10 to 63) and fluoroscopic time was 24 (12 to 60) min. RESULTS The majority of patients demonstrated an immediate decrease in the catheter pullback gradient (mean 78.5 ± 26.2 mm Hg pre-RFCA versus mean 36.1 ± 16.5 mm Hg post-RFCA, p < 0.01) and a further reduction in the Doppler echocardiographic gradient (mean 96.9 ± 27.0 mm Hg pre-RFCA versus 32.7 ± 27.1 mm Hg post-RFCA, p < 0.01) at follow-up. One patient died due to a paradoxical increase in left ventricular outflow tract obstruction, and another had persistent atrioventricular block that required permanent pacing. Six patients required further procedures (surgery, pacing, or further RFCA) during a median follow-up of 48 (3 to 144) months. CONCLUSIONS The preliminary results of RFCA for septal reduction in children with hypertrophic cardiomyopathy are promising and merit further evaluation.

Radiofrequency catheter septal ablation for hypertrophic obstructive cardiomyopathy in childhood

Wir beschreiben die Behandlung der Subaortenstenose durch Radiofrequenzkatheterablation (RFKA), bekannt aus der Ablationsbehandlung von Arrhythmien, bei 2 pädiatrischen Patienten. Bei einem 5 Jahre alten Kleinkind lag seit Geburt eine hypertrophe Kardiomyopathie mit zunehmender subaortaler Obstruktion vor. Unter medikamentöser Therapie fand sich bei ausgeprägter Obstruktion des linksventrikulären Ausflusstraktes ein Gradient von 50 mmHg in Ruhe. Dabei war der Patient eingeschränkt belastbar, zeigte geringen spontanen Bewegungsdrang und ermüdete schnell. Die zweite Patientin zeigte Symptome in Form von eingeschränkter körperlicher Belastbarkeit und geringem spontanem Bewegungsdrang. Zur Ablationstherapie wurde der Ablationskatheter retrograd in den linken Ventrikel eingebracht. Wegen des immanenten Risikos einer AV-Blockierung wurde das Erregungsleitungssystem am linken Septum anhand der charakteristischen His-Signale aufgesucht und in dem dreidimensionalen Navigationssystem LocaLisa® markiert. Nachfolgend erfolgte eine Serie von Ablationen im Bereich der subaortalen asymmetrischen Septumhypertrtophie beginnend in der Spitze des Ventrikels und endend unter der Aortenklappe, mit größtmöglichem Abstand von dem zuvor in LocaLisa® markierten Erregungsleitungssystem. Endpunkt der Prozedur war eine vollständige Behandlung des hypertrophierten Septums. Der peak-to-peak Gradient war vor der Ablation 50 mmHg bzw. 60 mmHg und war direkt nach der Ablation unverändert. Der Untergang von Herzmuskelgewebe wurde durch eine serielle Bestimmung von Troponin T und CKMB dokumentiert. Beide Patienten konnten nach 2 Tagen aus dem Krankenhaus entlassen werden. In der nach 7 Tagen und nach 6 Wochen durchgeführten ambulanten Nachkontrolle konnte echokardiographisch die hämodynamische Besserung mit Reduktion des LVOT-Gradienten und auch die klinische Besserung nachgewiesen werden. Wir schlussfolgern, dass die RFKA der Subaortenstenose eine Alternative zur operativen Resektion einer asymmetrischen Subaortenstenose bei HOCM mit der Option das Risiko für AV-Blockierunge zu reduzieren darstellt. Two patients, a 5 year old boy with progressive hypertrophic obstructive cardiomyopathy and increasing symptoms despite appropriate pharmacologic therapy and an 11 year old girl with symptoms of tiredness and peak instantaneous LVOT gradient of 80 and 90 mmHg respectively were considered for radiofrequency catheter septal ablation, to relieve the left ventricular outflow tract obstruction. Via a femoral arterial approach, the His bundle was initially plotted and marked using the LocaLisa navigation system. Subsequently, using a cooled tip catheter a series of lesions was placed in the hypertrophied septum, commencing distally in the ventricle and proceeding towards the aortic valve, taking care to stay away from the His bundle. The procedure was deemed to be completed when the entire extent of the hypertrophied septum had been treated. In the boy the procedure was complicated by two episodes of ventricular fibrillation, requiring DC cardioversion, but without any neurologic sequelae. The peak to peak gradient between left ventricle and aorta was 50 mmHg and 60 mmHg respectively pre-ablation, and remained unchanged immediately after. Both patients were discharged from the hospital 48 hours later. Serial measurement of serum Troponin T and CK-MB isoenzyme confirmed significant myocardial necrosis. Follow-up echocardiography at 7 days and at 6 weeks post-ablation respectively confirmed a beneficial hemodynamic result, with reduction of left ventricular outflow obstruction and relief of symptoms. In young children, in whom alcohol induced septal ablation is not an option, radiofrequency catheter ablation offers an alternative to surgery, with the benefits of repeatability and a lower risk of procedure-related permanent AV block.BACKGROUND The definitive therapeutic options for symptomatic obstructive cardiomyopathy in childhood are restricted. At present, extensive surgical myectomy is the only procedure that is of proven benefit. PATIENTS AND METHODS Three patients, aged 5, 11 and 17 years, respectively, with progressive hypertrophic obstructive cardiomyopathy and increasing symptoms were considered for radiofrequency catheter septal ablation. The peak Doppler gradient recorded on several occasions ranged between 50 to 90mmHg. Via a femoral arterial approach, the His bundle was initially plotted and marked using the LocaLisa navigation system. Subsequently, using a cooled tip catheter a series of lesions were placed in the hypertrophied septum, taking care to stay away from the His bundle. A total of 17, 50 and 45 lesions were applied in the three patients. In one case, the procedure was complicated by two episodes of ventricular fibrillation requiring DC cardioversion but without any neurological sequelae. RESULTS The preablation peak-to-peak gradient between left ventricle and aorta was 50 mmHg, 60 mmHg and 60 mmHg, respectively, and remained unchanged immediately after the procedure. All patients were discharged from hospital 48 hours later. Serial measurement of serum troponin T and CK-MB isoenzyme confirmed significant myocardial necrosis. Follow-up echocardiography both at seven days and at six weeks postablation confirmed a beneficial haemodynamic result, with reduction of left ventricular outflow obstruction and relief of symptoms. CONCLUSION In young children, in whom alcohol-induced septal ablation is not an option, radiofrequency catheter ablation offers an alternative to surgery, with the benefits of repeatability and a lower risk of procedure-related permanent AV block.

Combined transhepatic and transjugular approach for radiofrequency ablation of an accessory pathway in a child with complex congenital heart disease.

Die Radiofrequenz( RF)-Ablation einer akzessorischen Leitungsbahn bei Kindern ist eine anerkannte Therapie. Bei manchen Patienten ist dabei der Zugang durch die Femoralvene nicht möglich. Wir berichten über einen Jungen mit rezidivierender, therapieresistenter, hämodynamisch wirksamer atrioventrikukärer Reentry-Tachykardie. Der Patient hatte ein komplexes Vitium cordis mit rechtsatrialem Isomerismus, Systemvenenanomlie (spiegelbildlicher Verlauf der intrathorakalen Venen, Hemiazygos-Kontinuität auf der linken Seite, separate Mündung der Lebervenen in den systemvenösen Vorhof), angeboren korrigierte Transposition der großen Gefäße (ccTGA), Pulmonalatresie (PA), Ventrikel- und Vorhof-Septumdefekt (VSD, ASD). Im Alter von 22 Monaten planten wir eine RF-Ablation der akzessorischen Leitungsbahn. Den Zugang zum Herzen erreichten wir durch perkutane Punktion einer Lebervene, der linken V. jugularis, und retrograd über die Femoralarterie. Die früheste retrograde Überleitung in der Tachykardie fanden wir auf der systemvenösen Seite (linsseitiger AV-Klappenring) und die Ablation an dieser Stelle war erfolgreich. Komplikationen traten nicht auf. Zusammenfassend lässt sich sagen, dass die RF-Ablation einer akzessorischen Leitungsbahn auch bei Kindern mit komplexen strukturellen Herzerkrankungen und systemvenösen Anomalien durchführbar ist. In diesen Fällen ist der Zugang zum Herzen unter Berücksichtigung der anatomischen Verhältnisse zu planen. Falls erforderlich kann der transhepatische Zugang gewählt werden, sollte jedoch erfahrenen Untersuchern vorbehalten bleiben. We report on a boy with recurrent drug resistant atrioventricular reentrant tachycardia. The patient had complex structural heart disease consisting of right atrial isomerism, systemic venous anomaly (mirror image orientation of the intrathoracic veins, hemiazygos continuation to the left-sided superior vena cava, with separate drainage of the hepatic veins into the left-sided atrium, congenitally corrected transposition (ccTGA), pulmonary atresia (PA), ventricular and atrial septal defects (VSD and ASD). At the age of 22 months RF ablation was performed. Access to the heart was obtained by percutaneous puncture of a hepatic vein, the left internal jugular vein, and femoral artery. Earliest retrograde atrial conduction during tachycardia was localized to the free wall of the left-sided AV groove, and ablation in this area was successful. There were no procedure-related complications. RF ablation of accessory pathway is feasible in young children with complex structural heart disease and abnormal systemic venous return. In such patients access to the heart must be planned with the knowledge of the anatomy and judicious use of the hepatic venous approach, which should be done only by experienced investigators.

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.

Catheter ablation of junctional ectopic tachycardia in children, with preservation of atrioventricular conduction.

Die idiopathische junktionale ektope Tachykardie ist eine bei Kindern seltene Arrhythmie. Wie mehrere Studien zeigten, ist eine medikamentöse Behandlung oft nicht erfolgreich und häufig muss man sich mit einer Verlangsamung der Tachykardie-Frequenz begnügen. Frühes Auftreten und häufiges Wiederkehren sind mit einer schlechten Prognose assoziiert. Drei konsekutive Kinder im Alter von 9, 7 und 12 Jahren mit einer junktional ektopen Tachykardie wurden mittels Radiofrequenz-Katheter-Ablation behandelt, nachdem Versuche einer medikamentösen Therapie zuvor keinen Effekt gezeigt hatten. Zunächst wurde das gesamte His-Bündel wurde durch Mapping erfasst und im LocaLisa System markiert. Mittels intravenöser Isoprenalin-Infusion konnte die Arrhythmie leicht und reproduzierbar ausgelöst werden, so dass die ersten retrograden Signale während der Tachykardie erfasst und ebenfalls markiert werden konnten. Die Ablation erfolgte dann im Sinus-Rhythmus, im Bereich der zuvor bestimmten retrogaden Signale während der Tachykardie. Mit diesem Vorgehen konnte bei den ersten beiden Patienten mit superoparaseptalem Ablationsort die Tachykardie erfolgreich beseitigt werden. Bei dem dritten Patienten war die junktional ektope Tachykardie auslösbar obwohl die retrograde Aktivierung der Vorhöfe nach Ablation in einer septalen Position des Trikuspidalklappenringes unterbunden war. Nach weiteren Ablationen in der superoparaseptalen Region, näher am His-Bündel, zeigte sich die Tachykardie nicht mehr auslösbar. Nach einer medianen Nachbeobachtungsperiode von 10 Monaten hatten die Patienten—trotz Beendigung jeglicher Medikation, keine weiteren Tachykardie-Ereignisse. Die Radiofrequenz-Katheter-Ablation einer idiopathischen junktional ektopen Tachykardie ist unter Erhaltung der antegraden Überleitung möglich. Idiopathic junctional ectopic tachycardia is a rare arrhythmia in children. Several studies have demonstrated that drug therapy is often ineffective and sometimes the only achieved effect is rate control. Early presentation and frequent recurrence are associated with adverse outcome. Three consecutive children, aged 9, 7 and 12 years respectively, underwent radiofrequency catheter ablation for junctional ectopic tachycardia, after having failed antiarrhythmic drug therapy. The entire His bundle was plotted out and marked, using the Localisa navigation system. The arrhythmia was readily and repeatedly inducible using intravenous isoprenaline infusion and the site of earliest retrograde conduction during tachycardia could be assessed. Ablations were performed in sinus rhythm, empirically targeting the site of earliest retrograde conduction during tachycardia. This approach was successful in abolishing tachyarrhythmia in the first two patients, in whom the successful ablation site was located superoparaseptally. In the third patient, junctional ectopic tachycardia was inducible, despite abolishing retrograde atrial activation, in a septal location on the tricuspid valve annulus. Further ablations in the superoparaseptal region, closer to the His bundle, were successful in rendering tachyarrhythmia noninducible. Over a median follow-up of 10 months, none of the patients has had recurrence of arrhythmia, despite discontinuing all antiarrhythmic medications. Radio frequency catheter ablation of junctional ectopic tachycardia is feasible with preservation of atrioventricular conduction.

Superior vena cava stenting and transvenous pacemaker implantation (stent and pace) after the Mustard operation

SummaryThe Mustard operation for transposition of the great arteries is associated with good long-term survival. Typical complications at follow-up include progressive loss of sinus node function requiring permanent pacemaker implantation, and systemic venous pathway obstruction often precluding a transvenous approach to pacing. We report on 7 patients (median age 14.1; range 5–19) with bradyarrhythmia requiring permanent pacemaker implantation with associated stenosis (n = 6) or occlusion (n = 1) of the superior vena cava, in whom stent implantation relieved the obstruction and facilitated subsequent transvenous permanent pacing. In five of them stenting and pacemaker implantation were performed during a single procedure; two patients underwent elective pacemaker implantation 6 weeks later. In one patient the pacemaker had to be explanted due to pacemaker pocket infection. In the others the follow-up has been uneventful, with excellent chronic pacing thresholds and appropriate sensing. Two patients have had their generator replaced electively.We conclude that stenting of the SVC stenosis allows implantation of transvenous pacemaker leads with good intermediate term results in patients with a Mustard operation for transposition of the great arteries.

Slow pathway ablation in children with documented reentrant supraventricular tachycardia not inducible during invasive electrophysiologic study

Die Radiofrequenz-Katheter-Ablation ist die Methode der Wahl für die kurative Therapie der supraventrikulären Reentry Tachykardie (SVT). Wir berichten über unsere Erfahrungen mit der slow pathway Ablation am AV-Knoten bei Patienten mit dokumentierter SVT, ohne Nachweis einer akzessorischen Leitungsbahn und ohne induzierbare Tachyarrhythmie während der elektrophysiologischen Untersuchung (EPU). Wir untersuchten neun Kinder im Alter von 6–13 (Median 9) Jahren mit vorher aufgezeichneter SVT, die jedoch während der EPU nicht auslösbar war. Acht der neun Untersuchungen fanden in Allgemeinanästhesie statt. Eine akzessorische Leitungsbahn wurde bei allen Patienten durch atriale und ventrikuläre Stimulation mit Extrastimuli ausgeschlossen. Acht der neun Patienten hatten eine duale AV-Knoten-Physiologie, einer zeigte singuläre Echoschläge nach Extrastimulation. Die langsame Leitungsbahn des AV-Knotens (slow pathway) wurde durch Radiofrequenz-Läsionen inferoseptal in nähe der Trikuspidalklappe abladiert, wobei Temperaturen von über 50° an der Katheterspitze erreicht wurden. Das Auftreten von junktionalen Extrasystolen wurde als Indikator für einen erfolgreichen Ablationsort gewertet. Um die AV-Überleitung zu kontrollieren wurde bei junktionalen ES ein kontinuierliches schnelleres Vorhofpacing durchgeführt. Die Lage des Katheters und seine Position im Verhältnis zu dem His-Bündel AV-Knoten-System wurde kontinuierlich mittels des Navigationssystems Loca-Lisa® überwacht. Als Endpunkt der Behandlung wurde die Abwesenheit einer dualen AV-Knoten-Physiologie und/oder nodaler Echoschläge gewertet. Eine erfolgreiche Ablation der slow pathway gelang bei allen Patienten. Bei einem Patienten fanden sich 2 getrennte langsame Leitungsbahnen mit unterschiedlicher Lokalisation und doppeltem AH-Sprung. Beide wurden erfolgreich abladiert. Während des gesamten Follow-up von 4–36 Monaten (median 9 Monate) hatte kein Patient einen temporären oder permanenten AV-Block und bei keinem Patienten kam es zu erneuten Tachykardien. Bei Kindern mit strukturell normalem Herzen, zuvor dokumentierter supraventrikulärer Tachykardie, fehlender akzessorischer Leitungsbahn und während der EPU nicht auslösbarer Tachykardie, scheint eine empirische slow-pathway Ablation gerechtfertigt. Radiofrequency catheter ablation (RFA) has become the procedure of choice for permanent therapy of atrioventricular nodal reentrant tachycardia (AVNRT). This report presents our experience with atrio-ventricular node (AVN) modification in patients with documented narrow complex reentrant SVT, but no evidence for an accessory pathway, and no inducible tachyarrhythmia during invasive electrophysiology (EP) study. Methods The study population consists of nine children, age range 6–13 years (median 9) with previously documented SVT who had no tachyarrhythmia inducible during EP study (at baseline and following isoprenaline infusion). Eight of the 9 EP studies were performed under general anesthesia, and one under conscious sedation. An accessory pathway was excluded in all patients by appropriate atrial and ventricular extrastimulus pacing techniques. Eight of the nine patients had dual AV nodal physiology, and one had single AV nodal echo beats. The slow AV nodal pathway was empirically ablated, by applying RF lesions in the right inferoseptal AV groove, achieving catheter tip temperature of 50 °C. The appearance of an accelerated junctional rhythm during RF application was deemed to denote a successful application site. AV conduction during RF application was confirmed by incremental atrial pacing. The catheter position, and its relation to the compact AV node was constantly monitored using the LocaLisa navigation system. The end-point was absence of dual AVN physiology, and/or AV nodal echo beats. Results Successful slow pathway ablation was achieved in all patients. One patient appeared to have two separate slow pathways with different locations and two AH-jumps, which were both successfully ablated. None of the patients had evidence of temporary or permanent AV block at follow-up (median duration 9 months, range 4 to 36 months); none has had recurrence of symptoms or documented tachyarrhythmia. In children with structurally normal hearts, a previously documented SVT, absence of an accessory pathway and noninducibility of SVT during EP study, empirical slow pathway ablation appears to be justified.