Search PubMed⌕ Search

Biomedical subjects

K Brockmeier

Publications and source records attributed to K Brockmeier.

At least 19 recordsLinked to original sources
PubMed2007

[Sensorineural loss of hearing in lower registers as the main symptom of Lyme disease].

In a 9-year-old boy with sudden sensorineural loss of hearing in the lower registers in both ears, serology showed elevated levels of antibodies against Borrelia burgdorferi and examination of the CSF revealed a positive antibody index against Borrelia burgdorferi. The boy was treated with antibiotics for 2 weeks. Audiometry performed 4 weeks after treatment was completely normal. Inner ear involvement in Lyme disease has often been discussed. Treating these patients with antibiotics may lead to an improvement in some.

Child↗
PubMed2006

Transhepatic approach for catheter interventions in infants and children with congenital heart disease.

UNLABELLED: We report on our experience with transhepatic access for catheter interventions in six children (age range 2.5 months-9 years). Three had systemic venous anomalies, and one infant a femoral venous occlusion. In two further patients with bradyarrhythmia after a Fontan operation with an intraatrial Gore-Tex tunnel, transhepatic access was chosen to achieve a perpendicular orientation of the transseptal needle to the atrial baffle, allowing puncture of the Gore-Tex membrane. Two of the patients underwent ablation of an accessory pathway; in one an atrial septal defect was closed. A 2.5 month old baby after Norwood I operation, underwent balloon dilation of the pulmonary arteries. Two patients after prior Fontan surgery underwent DDDR pacemaker implantation. The size of the introducer sheath ranged from 4 F up to two 9 F introducers in the same vein for pacemaker insertion. At the end of the procedure, hemostasis was achieved by external compression. RESULTS: Transhepatic access could be established in all six patients (using a mirror image approach in children with left atrial isomerism) and the interventional procedures could be performed as planned. In one patient with implantation of a permanent pacemaker, a subcutaneous hematoma occurred, requiring blood transfusion. CONCLUSION: In selected pediatric patients, transhepatic access for catheter intervention can easily be achieved.

Angioplasty, Balloon↗
PubMed2005

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

BACKGROUND: 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. PATIENTS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: Radio frequency catheter ablation of junctional ectopic tachycardia is feasible with preservation of atrioventricular conduction.

Atrioventricular Node↗
PubMed2005

Radiofrequency catheter septal ablation for hypertrophic obstructive cardiomyopathy in childhood.

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.

Cardiomyopathy, Hypertrophic↗
PubMed2005

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

UNLABELLED: 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 degrees 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. CONCLUSIONS: 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.

Adolescent↗
PubMed2005

[Electrical heart diseases--therapy during childhood and adolescence].

With increasing experience, radiofrequency catheter ablation of tachyarrhythmia substrates has become first choice therapy for children >4 years of age with recurrent tachyarrhythmia. In younger patients, the risks associated with the procedure (typically procedure-related AV block or possible coronary artery damage) have to be weighed against the natural history of the tachyarrhythmia substrate, and the degree of control achieved with pharmacologic agents. Ablation for postoperative arrhythmias is more complicated, and associated with lower success rates and a higher rate of recurrence (of the same or a new tachyarrhythmia) despite acute procedural success. In this setting, catheter ablation has to be considered in conjunction with further surgery or the use of a defibrillator as a backup device to prevent arrhythmia-related sudden death. Also in inherited arrhythmias as in long QT syndrome and Brugada syndrome, implantable defibrillators have to be considered as a possible therapeutic option for patients with a higher risk for sudden cardiac death, irrespective of age.

Adolescent↗
PubMed2004

Fetal magnetocardiography: the clinician's viewpoint.

The fetal magnetocardiogram (FMCG) can be reliably recorded from approximately the 15th week of gestation onwards. The MCG has the ability to accurately record cardiac time intervals, and to provide a real-time recording that reflects cardiac electrical activity. Standardisation of the recording, signal processing, and measurement techniques can result in data that is reproducible, and when combined with the establishment of normal values for different gestational ages can be of clinical application universally, particularly in selected groups of patients at risk of potentially lethal arrhythmias.

Cardiotocography↗
PubMed2004

Identification and characterisation of a novel KCNQ1 mutation in a family with Romano-Ward syndrome.

Romano-Ward syndrome (RWS), the autosomal dominant form of the congenital long QT syndrome, is characterised by prolongation of the cardiac repolarisation process associated with ventricular tachyarrhythmias of the torsades de pointes type. Genetic studies have identified mutations in six ion channel genes, KCNQ1, KCNH2, SCN5A, KCNE1 and KCNE2 and the accessory protein Ankyrin-B gene, to be responsible for this disorder. Single-strand conformation polymorphism (SSCP) analysis and subsequent DNA sequence analysis have identified a KCNQ1 mutation in a family that were clinically conspicuous due to several syncopes and prolonged QTc intervals in the ECG. The mutant subunit was expressed and functionally characterised in the Xenopus oocyte expression system. A novel heterozygous missense mutation with a C to T transition at the first position of codon 343 (CCA) of the KCNQ1 gene was identified in three concerned family members (QTc intervals: 500, 510 and 530 ms, respectively). As a result, proline 343 localised within the highly conserved transmembrane segment S6 of the KCNQ1 channel is replaced by a serine. Co-expression of mutant (KCNQ1-P343S) and wild-type (KCNQ1) cRNA in Xenopus oocytes produced potassium currents reduced by approximately 92%, while IKs reconstitution experiments with a combination of KCNQ1 mutant, wild-type and KCNE1 subunits yielded currents reduced by approximately 60%. A novel mutation (P343S) identified in the KCNQ1 subunit gene of three members of a RWS family showed a dominant-negative effect on native IKs currents leading to prolongation of the heart repolarisation and possibly increases the risk of malign arrhythmias with sudden cardiac death.

Amino Acid Sequence↗
PubMed2004

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

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.

Catheter Ablation↗
PubMed2004

The Brugada syndrome. Its relevance to paediatric practice.

The diagnostic and therapeutic aspects of Brugada syndrome, one of the important genetic arrhythmias which causes sudden cardiac death in young people, and the relevance of this diagnostic entity to the paediatric population are briefly summarised. The role of diagnostic testing (genetic, pharmacologic and invasive electrophysiologic) for establishing the diagnosis and for risk stratification are discussed. Finally, while the implantable defibrillator is the only therapy of proven effectiveness in preventing sudden cardiac death, alternative therapies which are being considered (pharmacologic, hormonal and catheter ablation) are overviewed. The aim of this manuscript is to raise the awareness among doctors caring for young patients to the possibility of Brugada syndrome in patients presenting with potentially life-threatening symptoms of syncope or near-miss sudden death, and in index patients with a similar family history.

Adolescent↗
PubMed2003

Cardiac dysrhythmias in pediatric patients before and 1 year after transcatheter closure of atrial septal defects using the amplatzer septal occluder.

To prospectively assess the incidence of cardiac dysrhythmias before and after closure of atrial septal defects (ASDs) using the Amplatzer septal occluder (ASO), 24-hour Holter electrocardiograms (ECGs) were performed before and 1 year after the procedure in 23 pediatric patients (9 male and 14 female). Patients' ages ranged from 2 to 15 years (mean, 7.1 years). All had an ASD of the secundum type that was completely closed (n = 22) or had a small residual shunt (n = 1). No preexisting dysrhythmia was present in 22 patients; atrioventricular nodal reentrant tachycardia had been diagnosed in 1 patient. During the observation period, no clinical dysrhythmia occurred. Analysis of the Holter ECGs before the intervention showed regular sinus rhythm in 20 patients and sinus rhythm with intermittent atrial rhythm in 3 patients. Atrial premature complexes (APCs) were detected in 1 patient, and a ventricular couplet was present in 1 patient. The Holter ECG 1 year after the intervention showed sinus rhythm in 18 patients and sinus rhythm with intermittent atrial rhythm in 5 patients. APCs were still observed in 1 patient and seen for the first time in 1 patient; 1 patient and rare ventricular premature complexes. In conclusion, cardiac dysrhythmias on Holter ECG in pediatric patients before and 1 year after transcatheter ASD closure with the ASO device are rare and benign. Regular Holter monitoring seems to be useful in detecting late dysrhythmias.

Adolescent↗
PubMed2002

The index of pulmonary vascular disease in children with congenital heart disease: relationship to clinical and haemodynamic findings.

OBJECTIVE: We asked whether a scoring system [index of pulmonary vascular disease (IPVD)] that quantifies the individual pulmonary vascular pathology would relate to postoperative survival in patients with congenital heart disease and pulmonary hypertension (PH). METHODS: Lung biopsy specimens from 28 patients at a median age of 6 months (1 month to 21 years) were analysed qualitatively and morphometrically. The IPVD and other morphometric parameters were related to haemodynamic findings and survival. RESULTS: Mean pulmonary artery pressure (PAP) was 44 mmHg (15-72 mmHg), and the resistance to pulmonary perfusion was 5 U x m(2) (0.9-14 U x m(2)). There were three early (in-hospital) and three late deaths during the follow-up period of 2.5 years (6 months to 7 years). Incipient plexiform lesions were observed in one infant with trisomy 21 and complete atrioventricular septal defect (cAVSD). An IPVD score above the upper critical limit (>2.2) was not observed during the first year of life. On discriminant analysis, morphometric parameters could not predict mortality ( P=0.08). CONCLUSIONS: The IPVD is not helpful to predict surgical mortality during the first year of life. Patients with trisomy 21 and cAVSD may show advanced pulmonary vascular disease in infancy.

Child↗
PubMed2001

Electrophysiologic effects and efficacy of intravenous propafenone in terminating atrioventricular reentrant tachycardia in children.

In pediatric patients with atrioventricular reentrant tachycardia, intravenous propafenone exhibits its electrophysiologic effects in a dose-dependent manner by slowing or blocking retrograde conduction at the accessory connection. The high drug efficacy (81%) in terminating tachycardia is not dependent on patient age or retrograde conduction properties of the accessory connection.

Adolescent↗
PubMed2001

T-wave alternans in LQTS: repolarization-rate dynamics from digital 12-lead Holter data.

T-wave alternans (TWA) is a harbinger of ventricular vulnerability and an important prognostic indicator for torsade de pointes and likely sudden death in patients with LQTS. We analyzed the occurrence of TWA in 18 patients with LQTS (7 males, 11 females, ages ranging from 6 months to 32 years--median 8.4 years). Analysis was performed with software to investigate dynamics of cycle length mediated repolarization changes. Digital Holter ECG analysis revealed macroscopic, true TWA in 3 of 18 patients. TWA showed a variable morphological expression. One patient had continuous changes of T wave polarity, but not on a periodic beat-to-beat basis. Onsets of macroscopic TWA were preceded by long/short cycle length sequences and tachycardic rates above 130 to 140 bpm. Impact of ventricular premature beats on TWA onset was insignificant. Two of the identified patients with TWA had sudden cardiac death during follow-up (one refused PM therapy). At present, TWA cannot be detected automatically from Holter ECGs and therefore may be missed, despite the potential danger for the individuals. The observation that predominantly high beat rates and not beat rate changes, per se, triggered episodes of TWA renders difficult general therapeutic recommendations for the identified patients at risk.

Child↗
PubMed2001

Electrocardiographic measures of repolarization revisited: why? what? how?

Ventricular repolarization continues to be an enigma to clinical cardiologists and cardiac electrophysiologists. On the one hand, a century of experience has documented an association between abnormal T-wave morphology, QT prolongation and dispersion, T-wave alternans, and nonspecific ST-T waves with arrhythmia risk or negative prognostic outcome. On the other hand, recent advances in molecular electrophysiology have definitively implicated abnormal function and structure of cardiac ion channels associated with repolarization as primary arrhythmogenic mechanisms in long QT syndrome, Brugada's Syndrome, and idiopathic ventricular fibrillation and ventricular tachycardia. In spite of this extensive clinical experience and newly established mechanistic knowledge, robust measurements of repolarization and sensitive algorithms for reliable assessment of risk and prediction of arrhythmia occurrence have remained elusive. New insights into electrocardiographic waveform that reflect and capture the underlying spatial and dynamic characteristics of repolarization offer opportunity to devise clinical indices of repolarization that might be more predictive of risk or outcome than those currently used. Experimental and model data show evidence that the location and size of repolarization lesions may be deduced from T waveform. The changes of repolarization induced by altered activation sequence, and cycle length mediated alterations to repolarization offer additional means to assess the magnitude and significance of such lesions that are linked to increased arrhythmogenic risk. This article explores indices of repolarization that are sensitive to repolarization and its change and that provide opportunity to better characterize and assess repolarization for risk stratification.

Arrhythmias, Cardiac↗
PubMed2001

Occlusion of interatrial communications with the Amplatzer device: experience in 48 consecutive patients.

Both secundum atrial septal defect (ASD) and patent foramen ovale (PFO) have been closed interventionally using several different occluding devices. At a single institution we strived for interventional occlusion of interatrial communications using the Amplatzer device exclusively. During a study period of 22 months, we studied 48 patients ranging in age from 1 to 48 years with an ASD (n = 45) or a PFO (n = 3). Successful implantation of an Amplatzer device was possible in 92% of the patients, and 95% of these patients had a complete early closure of their defect. There were no complications related to the procedure. We conclude that interventional closure of interatrial communications with the Amplatzer device is feasible and safe for selected patients.

Adolescent↗