Neurosurgical treatment of pediatric brain tumors - results from a single center multidisciplinary setup

OBJECTIVE

The challenge of pediatric brain tumor surgery is given due to a relative low prevalence but high heterogeneity in age, localization, and pathology. Improvements of long-term overall survival rates were achieved during the past decades stressing the importance of a multidisciplinary decision process guided by a national treatment protocol. We reviewed the entire spectrum of pediatric brain tumor surgeries from the perspective of an interdisciplinary pediatric neuro-oncology center in Germany.

METHODS

Every patient who underwent brain tumor surgery from January 2010 to June 2017 in our Pediatric Neurosurgery department was retrospectively included and evaluated regarding the course of treatment. Perioperative data such as tumor localization, timing of surgery, extent of resection, neuropathological diagnosis, transfusion rates, oncologic and radiation therapy, and neurological follow-up including morbidity and mortality were evaluated.

RESULTS

Two hundred ninety-three pediatric brain tumor patients were applicable (age: 8.28 ± 5.62 years, 1.22:1.0 m:f). A total of 531 tumor surgical interventions was performed within these patients (457 tumor resections, 74 tumor biopsies; mean interventions per patient 1.8 ± 1.2). Due to a critical neurologic status, 32 operations (6%) were performed on the day of admission. In 65.2% of all cases, tumor were approached supratentorially. Most frequent diagnoses of the cases were glial tumors (47.8%) and embryonal tumors (17.6%). Preoperative planned extent of resection was achieved in 92.7%. Pre- and postoperative neurologic deficits resolved completely in 30.7%, whereas symptom regressed in 28.6% of surgical interventions. New postoperative neurologic deficit was observed in 10.7%, which resolved or improved in 80% of these cases during 30 days. The mortality rate was 1%.

CONCLUSION

We outlined the center perspective of a specialized pediatric neuro-oncological center describing the heterogeneous distribution of cases regarding age-related prevalence, tumor localization, and biology, which requires a high multidisciplinary expertise. The study contributes to define challenges in treating pediatric brain tumors and to develop quality indicators for pediatric neuro-oncological surgery. We assume that an adequate volume load of patients within a interdisciplinary infrastructure is warranted to aim for effective treatment and decent quality of life for the majority of long-term surviving pediatric tumor patients.

Antibiofilm and Antivirulence Properties of 6-Polyaminosteroid Derivatives against Antibiotic-Resistant Bacteria

The emergence of multi-drug resistant pathogens is a major public health problem, leading us to rethink and innovate our bacterial control strategies. Here, we explore the antibiofilm and antivirulence activities of nineteen 6-polyaminosterol derivatives (squalamine-based), presenting a modulation of their polyamine side chain on four major pathogens, i.e., carbapenem-resistant A. baumannii (CRAB) and P. aeruginosa (CRPA), methicillin-resistant S. aureus (MRSA), and vancomycin-resistant E. faecium (VRE) strains. We screened the effect of these derivatives on biofilm formation and eradication. Derivatives 4e (for CRAB, VRE, and MRSA) and 4f (for all the strains) were the most potent ones and displayed activities as good as those of conventional antibiotics. We also identified 11 compounds able to decrease by more than 40% the production of pyocyanin, a major virulence factor of P. aeruginosa. We demonstrated that 4f treatment acts against bacterial infections in Galleria mellonella and significantly prolonged larvae survival (from 50% to 80%) after 24 h of CRAB, VRE, and MRSA infections. As shown by proteomic studies, 4f triggered distinct cellular responses depending on the bacterial species but essentially linked to cell envelope. Its interesting antibiofilm and antivirulence properties make it a promising a candidate for use in therapeutics.

Biopsies of caudal brainstem tumors in pediatric patients - a single center retrospective case series

OBJECTIVE

The indication for performing biopsies in patients with diffuse lesions in the brain stem is controversial. Possible risks associated with the technical challenging interventions need to be balanced against clarifying the diagnosis and possible therapeutic options. We reviewed the feasibility, risk profile and diagnostic yield of different biopsy techniques in a pediatric cohort.

METHODS

We retrospectively included all patients under 18 years of age that received a biopsy of the caudal brainstem region (pons, medulla oblongata) at our pediatric neurosurgical center from 2009-2022.

RESULTS

We identified 27 children. Biopsies were performed using frameless stereotactic (Varioguide) (n=12), robotic assisted (Autoguide) (n=4), endoscopic (n=3) and open biopsy (n=8) technique. Intervention related mortality was not observed. Three patients experienced transient post-surgical neurological deficit. No patient showed intervention related permanent morbidity. Biopsy yielded histopathological diagnosis in all cases. Molecular analysis was feasible in 97% of cases. Most common diagnosis was H3K27M mutated diffuse midline glioma (60%). Low-grade gliomas were identified in 14%. Overall survival was 62.5% after 24 months of follow up.

CONCLUSION

Biopsies of the caudal brainstem in children were feasible and safe in the presented setup. The amount of acquired tumor material allowing integrated diagnosis and was obtained at reasonable risk. The selection of the surgical technique depends on tumor location and growth pattern. We recommend brainstem tumor biopsies in children being performed at specialized centers to better understand the biology and enable possible novel therapeutic options.

MacAB-TolC Contributes to the Development of Acinetobacter baumannii Biofilm at the Solid–Liquid Interface

Acinetobacter baumannii has emerged as one of the most problematic bacterial pathogens responsible for hospital-acquired and community infections worldwide. Besides its high capacity to acquire antibiotic resistance mechanisms, it also presents high adhesion abilities on inert and living surfaces leading to biofilm development. This lifestyle confers additional protection against various treatments and allows it to persist for long periods in various hospital niches. Due to their remarkable antimicrobial tolerance, A. baumannii biofilms are difficult to control and ultimately eradicate. Further insights into the mechanism of biofilm development will help to overcome this challenge and to develop novel antibiofilm strategies. To unravel critical determinants of this sessile lifestyle, the proteomic profiles of two A. baumannii strains (ATTC17978 and SDF) grown in planktonic stationary phase or in mature solid–liquid (S-L) biofilm were compared using a semiquantitative proteomic study. Of interest, among the 69 common proteins determinants accumulated in the two strains at the S-L interface, we sorted out the MacAB-TolC system. This tripartite efflux pump played a role in A. baumannii biofilm formation as demonstrated by using ΔmacAB-tolC deletion mutant. Complementary approaches allowed us to get an overview of the impact of macAB-tolC deletion in A. baumannii physiology. Indeed, this efflux pump appeared to be involved in the envelope stress response occurring in mature biofilm. It contributes to maintain wild type (WT) membrane rigidity and provides tolerance to high osmolarity conditions. In addition, this system is probably involved in the maintenance of iron and sulfur homeostasis. MacAB-TolC might help this pathogen face and adapt to deleterious conditions occurring in mature biofilms. Increasing our knowledge of A. baumannii biofilm formation will undoubtedly help us develop new therapeutic strategies to tackle this emerging threat to human health.

Retrospective single-center historical comparative study between proGAV and proGAV2.0 for surgical revision and implant duration

OBJECTIVE

Cerebrospinal fluid (CSF) diversion shunt systems remain to be the most common treatment for pediatric hydrocephalus. Different valve systems are used to regulate CSF diversion. Preventing complications such as occlusions, ruptures, malpositioning, and over- or underdrainage are the focus for further developments. The proGAV and proGAV2.0 valve system are compared in this retrospective study for revision-free survival and isolated valve revision paradigms.

METHODS

In the first part of the study, the shunt and valve revision-free survival rates were investigated in a retrospective historical comparison design for a period of 2 years in which each valve was used as standard valve (proGAV: July 2012-June 2014; proGAV2.0: January 2015-December 2016) with subsequent 30-month follow-up period, respectively. In the second part of the study, the implant duration was calculated by detecting isolated valve (valve-only) revisions together with another valve explantation during the entire period of the first study and its follow-up period.

RESULTS

Two hundred sixty-two patients (145 male and 117 female, mean age 6.2 ± 6.1 years) were included in the cohort of revision-free survival. During the 30-month follow-up period, 41 shunt revisions, including 27 valve revisions (shunt survival rate: 72.1%, valve survival rate: 81.6%) were performed in the proGAV cohort and 37 shunt revisions, including 21 valve revisions (shunt survival rate: 74.8% and valve survival rate: 85.0%) were performed in the proGAV2.0 cohort without showing statistically significant differences. In the second part of the study, 38 cases (mean age 4.0 ± 3.9 years) met the inclusion criteria of receiving a valve-only-revision. In those patients, a total of 44 proGAV and 42 proGAV2.0 were implanted and explanted during the entire study time. In those, a significantly longer implant duration was observed for proGAV (mean valve duration 961.9 ± 650.8 days) compared to proGAV2.0 (mean length of implantation period 601.4 ± 487.8 days; p = 0.004).

CONCLUSION

The shunt and valve revision-free survival rates were found to be similar among the groups during 30 month follow-up. In patients who received "valve only" revisions and a subsequent explanation, the implant duration was significantly longer in the proGAV. Although the amount of patients with valve-only-revisions are small compared to the entire cohort certain patients seem to be at higher risk for repeated valve revisions.

TROPHY registry - status report

INTRODUCTION

The TROPHY registry has been established to conduct an international multicenter prospective data collection on the surgical management of neonatal intraventricular hemorrhage (IVH)-related hydrocephalus to possibly contribute to future guidelines. The registry allows comparing the techniques established to treat hydrocephalus, such as external ventricular drainage (EVD), ventricular access device (VAD), ventricular subgaleal shunt (VSGS), and neuroendoscopic lavage (NEL). This first status report of the registry presents the results of the standard of care survey of participating centers assessed upon online registration.

METHODS

On the standard of treatment forms, each center indicated the institutional protocol of interventions performed for neonatal post-hemorrhagic hydrocephalus (nPHH) for a time period of 2 years (Y1 and Y2) before starting the active participation in the registry. In addition, the amount of patients enrolled so far and allocated to a treatment approach are reported.

RESULTS

According to the standard of treatment forms completed by 56 registered centers, fewer EVDs (Y1 55% Y2 46%) were used while more centers have implemented NEL (Y1 39%; Y2 52%) to treat nPHH. VAD (Y1 66%; Y2 66%) and VSGS (Y1 42%; Y2 41%) were used at a consistent rate during the 2 years. The majority of the centers used at least two different techniques to treat nPHH (43%), while 27% used only one technique, 21% used three, and 7% used even four different techniques. Patient data of 110 infants treated surgically between 9/2018 and 2/2021 (13% EVD, 15% VAD, 30% VSGS, and 43% NEL) were contributed by 29 centers.

CONCLUSIONS

Our results emphasize the varying strategies used for the treatment of nPHH. The international TROPHY registry has entered into a phase of growing patient recruitment. Further evaluation will be performed and published according to the registry protocol.

Membrane phospholipid composition of Pseudomonas aeruginosa grown in a cystic fibrosis mucus-mimicking medium

BACKGROUND

Pseudomonas aeruginosa is a bacterium able to induce serious pulmonary infections in cystic fibrosis (CF) patients. This bacterium is very often antibiotic resistant, partly because of its membrane impermeability, which is linked to the membrane lipid composition. This work aims to study the membrane phospholipids of P. aeruginosa grown in CF sputum-like media.

METHODS

Three media were used: Mueller Hilton broth (MHB), synthetic cystic fibrosis medium (SCFM) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) complemented SCFM (SCFM-PC). Lipids were extracted and LC-MS/MS analyses were performed. Growth curves, atomic force microscopy images and minimal inhibitory concentration determination were performed in order to compare the growth and potentially link lipid modifications to antibiotic resistance.

RESULTS

Semi-quantification showed phospholipid quantity variation depending on the growth medium. Phosphatidylcholines were detected in traces in SCFM. MS/MS experiments showed an increase of phospholipids derived from DOPC in SCFM-PC. We observed no influence of the medium on the bacterial growth and a minor influence on the bacterial shape. MIC values were generally higher in SCFM and SCFM-PC than in MHB.

CONCLUSIONS

We defined a CF sputum-like media which can be used for the membrane lipid extraction of P. aeruginosa. We also showed that the growth medium does have an influence on its membrane lipid composition and antibiotic resistance, especially for SCFM-PC in which P. aeruginosa uses DOPC, in order to make its own membrane.

GENERAL SIGNIFICANCE

Our results show that considerable caution must be taken when choosing a medium for lipid identification and antibiotic testing -especially for phospholipids-enriched media.

Endoscopic third ventriculostomy in children with third ventricular pressure gradient and open ventricular outlets on MRI

OBJECTIVE

Patients with non-communicating hydrocephalus due to aqueductal stenosis are often successfully treated with endoscopic third ventriculocisternostomy (ETV). In hydrocephalus, due to other locations of obstruction of the major CSF pathways, endoscopic treatment may also be a good option. We investigated our cohort of patients treated by ETV with patent ventricular outflow but pressure gradient signs at the third ventricle in a single-center retrospective study.

METHODS

We retrospectively reviewed records and imaging studies of 137 patients who underwent an ETV in our department in the time period of June 2010 to March 2018. We included patients who showed the following findings in MRI: 1st: open Sylvian aqueduct, 2nd: open outlets of the 4th ventricle, 3rd: open spinal canal, 4th: intra-/extraventricular pressure gradient seen at the 3rd ventricle and excluded patients with history of CSF infection or hemorrhage. Perioperative clinical state and possible complications or reoperations were recorded. Shunt dependency and changes in ventricular dilatation were measured as frontal and occipital horn ratio (FOHR) before surgery and during follow-up.

RESULTS

A total of 21 patients met the defined criteria. During the mean follow-up time of 40.7 ± 30 months (range; 5-102 months), two children had to undergo a re-ETV, and six children (all < 1 year of age) received a VP shunt. ETV shunt-free survival was 100% for children > 1 year of age. The ventricular width measured as FOHR was significantly reduced after ETV 0.5 ± 0.08 (range 0.42-0.69; p < 0.05). FOHR was significantly reduced at last follow-up shunt independent patients (0.47 ± 0.05; range 0.41-0.55; p < 0.001) CONCLUSION: We conclude that ETV seems to be a successful treatment option for patients with MRI signs of intra-/extraventricular pressure gradient at the 3rd ventricle and patent aqueduct and fourth ventricular outlets in children older than 1 year of age. This condition is observed only rarely and warrants further research on a multicenter basis in order to get more solid data of its pathophysiology.

Chronic wound healing: A specific antibiofilm protein-asymmetric release system

Chronic infection is a major cause of delayed wound-healing. It is recognized to be associated with infectious bacterial communities called biofilms. Currently used conventional antibiotics alone often reveal themselves ineffective, since they do not specifically target the wound biofilm. Here, we report a new conceptual tool aimed at overcoming this drawback: an antibiofilm drug delivery system targeting the bacterial biofilm as a whole, by inhibiting its formation and/or disrupting it once it is formed. The system consists of a micro/nanostructured poly(butylene-succinate-co-adipate) (PBSA)-based asymmetric membrane (AM) with controlled porosity. By the incorporation of hydrophilic porogen agents, polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG), we were able to obtain AMs with high levels of porosity, exhibiting interconnections between pores. The PBSA-PEG membrane presented a dense upper layer with pores small enough to block bacteria penetration. Upon using such porogen agents, under dry and wet conditions, membrane's integrity and mechanical properties were maintained. Using bovine serum albumin (BSA) as a model protein, we demonstrated that protein loading and release from PBSA membranes were affected by the membrane structure (porosity) and the presence of residual porogen. Furthermore, the release curve profile consisted of a fast initial slope followed by a second slow phase approaching a plateau within 24 h. This can be highly beneficial for the promotion of wound healing. Cross-sectional confocal laser scanning microscopy (CLSM) images revealed a heterogeneous distribution of fluorescein isothiocyanate (FITC) labeled BSA throughout the entire membrane. PBSA membranes were loaded with dispersin B (DB), a specific antibiofilm matrix enzyme. Studies using a Staphylococcus epidermidis model, indicate significant efficiency in both inhibiting or dispersing preformed biofilm (up to 80 % eradication). The asymmetric PBSA membrane prepared with the PVP porogen (PBSA-PVP) displayed highest antibiofilm activity. Moreover, in vitro cytotoxicity assays using HaCaT and reconstructed human epidermis (RHE) models revealed that unloaded and DB-loaded PBSA-PVP membranes had excellent biocompatibility suitable for wound dressing applications.

Dynamic cerebellar herniation in Chiari patients during the cardiac cycle evaluated by dynamic magnetic resonance imaging

PURPOSE

Cerebellar herniation in Chiari patients can be dynamic, following the cerebrospinal fluid pulsatility during the cardiac cycle. We present a voxel intensity distribution method (VIDM) to automatically extract the pulsatility-dependent herniation in time-resolved MRI (CINE MRI) and compare it to the simple linear measurements. The degree of herniation is furthermore compared on CINE and static sequences, and the cerebellar movement is correlated to the presence of hydrocephalus and syringomyelia.

METHODS

The cerebellar movement in 27 Chiari patients is analyzed with VIDM and the results were compared to linear measurements on an image viewer (visual inspection, VI) using a paired t test. Second, an ANOVA test is applied to compare the degree of herniation on static 3D MRI and CINE. Finally, the Pearson's correlation coefficient is calculated for the correlation between cerebellar movement and the presence of hydrocephalus and syringomyelia.

RESULTS

VIDM showed significant movement in 85% of our patients. Assuming that movement < 1 mm cannot be detected reliably on an image viewer, VI identified movement in 29.6% of the patients (p = 0.002). The herniation was greater on static sequences than on CINE in most cases, but this was not statistically significant. The cerebellar movement was not correlated with hydrocephalus or syringomyelia (Pearson's coefficient < 0.3).

CONCLUSIONS

VIDM is a sensitive method to detect tissue movement on CINE MRI and could be used for Chiari patients, but also for the evaluation of cyst membranes, ventriculostomies, etc. The cerebellar movement appears not to correlate with hydrocephalus and syringomyelia in Chiari patients.

Neuroendoscopic lavage for the treatment of CSF infection with hydrocephalus in children

OBJECTIVE

The treatment of infectious CSF condition with ventriculitis and hydrocephalus in children is an interdisciplinary challenge. Conventional surgical treatment includes external ventricular drain (EVD) and systemic antibiotic therapy. However, infectious contamination of large ventricles combined with CSF protein overload often requires long treatment regimens. We retrospectively investigated neuroendoscopic lavage as a new option for clearance of CSF in children with hydrocephalus and active CSF infection.

PATIENTS AND METHODS

A database review identified 50 consecutive patients treated for CSF infection with hydrocephalus at our institution. Twenty-seven patients (control group, CG) were treated conventionally between 2004 and 2010, while 23 patients (neuroendoscopic group, NEG) underwent neuroendoscopic lavage for removal of intraventricular debris between 2010 and 2015. Clinical data, microbiology, laboratory measures, shunt dependency, and shunt revision rate were evaluated retrospectively.

RESULTS

The patient groups did not differ regarding basic clinical characteristics. Patients in NEG received neuroendoscopic lavage at mean of 1.6 ± 1times (1-4). No immediate postoperative complications were observed in NEG patients. Shunt rate in NEG patients was 91% as compared 100% in CG patients (p = 0.109). Within 24 months after shunt implantation, incidence of shunt revision was higher in CG (23/27) compared to NEG (5/23; p < 0.001). Reinfection was observed more often in CG (n = 17) compared to one patient in NEG (p < 0.001).

CONCLUSIONS

We experienced that neuroendoscopic lavage is a safe and effective treatment for hydrocephalus in children with infectious conditions. Neuroendoscopic lavage resulted in a decreased number of overall shunt revisions in shunt-depended patients as well as a lower number of recurrent infections.

The use of a smartphone-assisted ventricle catheter guide for Ommaya reservoir placement-experience of a retrospective bi-center study

BACKGROUND

For intraventricular chemotherapy (IVC) as part of many oncological treatment protocols, Ommaya reservoir is enabling repeated access to the cerebro-spinal fluid (CSF). The correct placement of the catheter in the ventricle is essential for correct application of drugs, which is enabled by sophisticated techniques such as neuronavigation.

OBJECTIVE

In a bi-center retrospective study, we reviewed our experience using a smartphone-assisted ventricle catheter guide as simple solution for correct Ommaya reservoir placement.

METHODS

Sixty Ommaya reservoirs have been placed in 60 patients between 2011 and 2017 with the smartphone-assisted ventricular catheter guidance technique. Patient characteristics, preoperative frontal and occipital horn ratio (FOHR), postoperative catheter position, and complications were assessed.

RESULTS

The majority of our patients (71.6%) have got narrow or slit-like ventricles (FOHR ≤ 0.4). All Ommaya reservoirs were placed successfully. Fifty-eight ventricular catheters (97%) were inserted at the first and 2 (3%) at the second attempt using the same technique. No immediate perioperative complications were observed. All catheters (100%) could be used for IVC. Postoperative imaging was available in 52 patients. Thirty-two (61.5%) of ventricular catheters were rated as grade I, 20 (38.5%) as grade II, and none (0%) as grade III. Four patients (6.7%) showed postoperative complications during a median follow-up of 8.5 months (hydrocephalus, n = 1; infection, n = 1; parenchymal cyst around catheter, n = 1; shunt revision, n = 1).

CONCLUSIONS

The smartphone-assisted guide offers decent accuracy of ventricle catheter placement with ease and simplicity for a small surgical intervention. We propose this technique as routine tool for Ommaya reservoir placement independent of lateral ventricular size to decrease the rate of ventricle catheter malposition as reasonable alternative to a neuronavigation system.

Augmented reality in intraventricular neuroendoscopy

BACKGROUND

Individual planning of the entry point and the use of navigation has become more relevant in intraventricular neuroendoscopy. Navigated neuroendoscopic solutions are continuously improving.

OBJECTIVE

We describe experimentally measured accuracy and our first experience with augmented reality-enhanced navigated neuroendoscopy for intraventricular pathologies.

PATIENTS AND METHODS

Augmented reality-enhanced navigated endoscopy was tested for accuracy in an experimental setting. Therefore, a 3D-printed head model with a right parietal lesion was scanned with a thin-sliced computer tomography. Segmentation of the tumor lesion was performed using Scopis NovaPlan navigation software. An optical reference matrix is used to register the neuroendoscope's geometry and its field of view. The pre-planned ROI and trajectory are superimposed in the endoscopic image. The accuracy of the superimposed contour fitting on endoscopically visualized lesion was acquired by measuring the deviation of both midpoints to one another. The technique was subsequently used in 29 cases with CSF circulation pathologies. Navigation planning included defining the entry points, regions of interests and trajectories, superimposed as augmented reality on the endoscopic video screen during intervention. Patients were evaluated for postoperative imaging, reoperations, and possible complications.

RESULTS

The experimental setup revealed a deviation of the ROI's midpoint from the real target by 1.2 ± 0.4 mm. The clinical study included 18 cyst fenestrations, ten biopsies, seven endoscopic third ventriculostomies, six stent placements, and two shunt implantations, being eventually combined in some patients. In cases of cyst fenestrations postoperatively, the cyst volume was significantly reduced in all patients by mean of 47%. In biopsies, the diagnostic yield was 100%. Reoperations during a follow-up period of 11.4 ± 10.2 months were necessary in two cases. Complications included one postoperative hygroma and one insufficient fenestration.

CONCLUSIONS

Augmented reality-navigated neuroendoscopy is accurate and feasible to use in clinical application. By integrating relevant planning information directly into the endoscope's field of view, safety and efficacy for intraventricular neuroendoscopic surgery may be improved.

Valve exchange towards an adjustable differential pressure valve with gravitational unit, clinical outcome of a single-center study

OBJECTIVE

Overdrainage in children is a long-term problem for shunted patients which might lead to chronic anatomical changes. In order to prevent these problems, valve exchange is performed on a regular basis in patients without hydrostatic units towards a valve with both an adjustable and a gravitational unit. The clinical outcome of these patients is reported in a retrospective study.

METHODS

Between 2009 and 2014, the in-house database was analyzed for patients who received a valve exchange towards an adjustable differential pressure valve with gravitational unit. The study protocol included the patients shunt history, image analysis for ventricular width, and necessity of revision surgery after valve exchange. A questionnaire was sent to the patients in order to ask for their subjective experience for symptom changes and treatment experience.

RESULTS

Forty-six patients were identified (26 girls, mean age 11.8 ± 6.1 years) with a mean follow-up of 36.3 ± 15 months. The ventricular width did increase after valve exchange as measured in frontal and occipital horn ratio (0.364 ± 0.032 vs. 0.402 ± 0.09, p = 0.0017). Of the patients suffering from acute symptoms, 89% improved after treatment. The shunt and valve survival rates were 88 and 95%, respectively, after 12 months. Comparing the total amount of revisions before and after valve exchange, a significant reduction was seen in total but a no significant difference was analyzed in amount of revisions to time ratio.

CONCLUSION

Valve exchange might be cautiously decided if patients seem to perform clinically well. In our study, we were able to show that the strategy of valve exchange to prevent chronic overdrainage is well tolerated and seem to improve patient's clinical outcome in terms of ventricular width, symptom relieve, and revision rate.

COXIBRAIN: results of the prospective, randomised, phase II/III study for the selective COX-2 inhibition in chronic subdural haematoma patients

BACKGROUND

Chronic subdural haematomas (cSDHs) have shown an increasing incidence in an ageing population over the last 20 years, while unacceptable recurrence rates of up to 30 % persist. The recurrence rate of cSDH seems to be related to the excessive neoangiogenesis in the parietal membrane, which is mediated via vascular endothelial growth factor (VEGF). This is found to be elevated in the haematoma fluid and is dependent on eicosanoid/prostaglandin and thromboxane synthesis via cyclo-oxygenase-2 (COX-2). With this investigator-initiated trial (IIT) it was thought to diminish the recurrence rate of operated-on cSDHs by administering a selective COX-2 inhibitor (Celecoxib) over 4 weeks' time postoperatively in comparison to a control group.

METHOD

The thesis of risk reduction of cSDH recurrence in COX-2-inhibited patients was to be determined in a prospective, randomised, two-armed, open phase-II/III study with inclusion of 180 patients over a 2-year time period in four German university hospitals. The treated- and untreated-patient data were to be analysed by Fisher's exact test (significance level of alpha, 0.05 [two-sided]).

RESULTS

After screening of 246 patients from January 2009 to April 2010, the study had to be terminated prematurely as only 23 patients (9.3 %) could be enrolled because of on-going non-steroid anti-rheumatic (NSAR) drug treatment or contraindication to Celecoxib medication. In the study population, 13 patients were treated in the control group (six women, seven men; average age 66.8 years; one adverse event (AE)/serious adverse event (SAE) needing one re-operation because of progressive cSDH (7.7 %); ten patients were treated in the treatment group (one woman, nine men; average age 64.7 years; five AEs/SAEs needing two re-operations because of one progressive cSDH and one wound infection [20 %]). Significance levels are obsolete because of insufficient patient numbers.

CONCLUSIONS

The theoretical advantage of COX-2 inhibition in the recurrent cSDH could not be transferred into the treatment of German cSDH patients as 66.6 % of the patients showed strict contraindications for Celecoxib. Furthermore, 55 % of the patients were already treated with some kind of COX-2 inhibition and, nevertheless, developed cSDH. Thus, although conceptually appealing, an anti-angiogenic therapy with COX-2 inhibitors for cSDH could not be realised in this patient population due to the high prevalence of comorbidities excluding the administration of COX2 inhibitors.

Smartphone-assisted guide for the placement of ventricular catheters

OBJECTIVE

Freehand placement of ventricular catheters (VC) is reported to be inaccurate in 10-40 %. Endoscopy, ultrasound, or neuronavigation are used in selected cases with significant technical and time-consuming efforts. We suggest a smartphone-assisted guiding tool for the placement of VC.

METHODS

Measurements of relevant parameters in 3D-MRI datasets in a patient cohort with narrow ventricles for a frontal precoronal VC placement were performed. In this context, a guiding tool was developed to apply the respective measures for VC placement. The guiding tool was tested in a phantom followed by CT imaging to quantify placement precision. A smartphone application was designed to assist the relevant measurements. The guide was applied in 35 patients for VC placement.

RESULTS

MRI measurements revealed the rectangular approach in the sagittal plane and the individual angle towards the tangent in the coronal section as relevant parameter for a frontal approach. The latter angle ranged from medial (91.96° ± 2.75°) to lateral margins (99.56° ± 4.14°) of the ventricle, which was similar in laterally shifted (±5 mm) entry points. The subsequently developed guiding tool revealed precision measurements in an agarose model with 1.1° ± 0.7° angle deviation. Using the smartphone-assisted guide in patients with narrow ventricles (frontal occipital horn ratio, 0.38 ± 0.05), a primary puncture of the ventricles was possible in all cases. No VC failure was observed during follow-up (9.1 ± 5.3 months).

CONCLUSIONS

VC placement in narrow ventricles requires accurate placement with simple means in an every-case routine. The suggested smartphone-assisted guide meets these criteria. Further data are planned to be collected in a prospective randomized study.

Enhanced adhesion of Campylobacter jejuni to abiotic surfaces is mediated by membrane proteins in oxygen-enriched conditions

Campylobacter jejuni is responsible for the major foodborne bacterial enteritis in humans. In contradiction with its fastidious growth requirements, this microaerobic pathogen can survive in aerobic food environments, suggesting that it must employ a variety of protection mechanisms to resist oxidative stress. For the first time, C. jejuni 81-176 inner and outer membrane subproteomes were analyzed separately using two-dimensional protein electrophoresis (2-DE) of oxygen-acclimated cells and microaerobically grown cells. LC-MS/MS analyses successfully identified 42 and 25 spots which exhibited a significantly altered abundance in the IMP-enriched fraction and in the OMP-enriched fraction, respectively, in response to oxidative conditions. These spots corresponded to 38 membrane proteins that could be grouped into different functional classes: (i) transporters, (ii) chaperones, (iii) fatty acid metabolism, (iv) adhesion/virulence and (v) other metabolisms. Some of these proteins were up-regulated at the transcriptional level in oxygen-acclimated cells as confirmed by qRT-PCR. Downstream analyses revealed that adhesion of C. jejuni to inert surfaces and swarming motility were enhanced in oxygen-acclimated cells or paraquat-stressed cells, which could be explained by the higher abundance of membrane proteins involved in adhesion and biofilm formation. The virulence factor CadF, over-expressed in the outer membrane of oxygen-acclimated cells, contributes to the complex process of C. jejuni adhesion to inert surfaces as revealed by a reduction in the capability of C. jejuni 81-176 ΔCadF cells compared to the isogenic strain.Taken together, these data demonstrate that oxygen-enriched conditions promote the over-expression of membrane proteins involved in both the biofilm initiation and virulence of C. jejuni.

Analysis of LuPME3, a pectin methylesterase from Linum usitatissimum, revealed a variability in PME proteolytic maturation

Pectin methylesterase (PME) catalyses the de-methylesterification of pectin in plant cell walls during cell elongation. (1) Pectins are mainly composed of α(1, 4)-D-galacturonosyl acid units that are synthesised in a methylesterified form in the Golgi apparatus to prevent any interaction with Ca2+ ions during their intracellular transport. (2) The highly methylesterified pectins are then secreted into the apoplasm (3) and subsequently de-methylesterified in muro by PMEs. This can either induce the formation of pectin gels through the Ca2+ crosslinking of neighbouring non-methylesterified chains or create substrates for pectin-degrading enzymes such as polygalacturonases and pectate lyases for the initiation of cell wall loosening. (4) PMEs belong to a large multigene family. Sixty-six PME-related genes are predicted in the Arabidopsis genome. (1) Among them, we have recently shown that AtPME3 (At3g14310), a major basic PME isoform in A. thaliana, is ubiquitously expressed in vascular tissues and play a role in adventitious rooting. (5) In flax (Linum usitatissimum), three genes encoding PMEs have been sequenced so far, including LuPME3, the orthologue of AtPME3. Analysis of the LuPME3 isoform brings new insights into the processing of these proteins.

[Stored electrograms in pacemakers and ICDs from Boston Scientific]

The storage of electrograms in pacemakers and ICDs represents an important step forward in the detection of asymptomatic arrhythmias (e.g., paroxysmal atrial fibrillation) and the distinction between appropriate and inappropriate therapies. This review presents via clinical examples the information provided in stored electrograms in systems from Boston Scientific and tips how to interpret them.

Temporal regulation of cell-wall pectin methylesterase and peroxidase isoforms in cadmium-treated flax hypocotyl

BACKGROUND AND AIMS

In hypocotyls of flax (Linum usitatissimum) cadmium-induced reorientation of growth (i.e. an increase in expansion and a decrease in elongation) coincides with marked changes in the methylesterification and cross-linking of homogalacturonans within various cell-wall (CW) domains. The aim of the present study was to examine the involvement of pectin methylesterase (PME) and peroxidase (PER) in this cadmium-induced CW remodelling.

METHODS

CW proteins were extracted from hypocotyls of 10- and 18-d-old flax that had been treated or not treated with 0.5 mm Cd(NO(3))(2). PME and PER expression within these extracts was detected by LC/MS, by isoelectric focusing and enzyme activity assays. Transcript expression by RT-PCR of known flax PME and PER genes was also measured in corresponding samples.

KEY RESULTS

In cadmium-treated seedlings, PME activity increased as compared with controls, particularly at day 10. The increased activity of PME was accompanied by increased abundance of both a basic protein isoform (B2) and a particular transcript (Lupme5). In contrast, induction of PER activity by cadmium was highest at day 18. Among the four reported PER genes, Flxper1 and 3 increased in abundance in the presence of cadmium at day 18.

CONCLUSIONS

The temporal regulation of Lupme and Flxper genes and of their respective enzyme activities fits the previously reported cadmium-induced structural changes of homogalacturonans within the CWs. After PME-catalysed de-esterification of homogalacturonans, their cross-linking would depend on the activity of PERs interacting with calcium-dimerized blocks and reinforce the cell cohesion during the cadmium-induced swelling.

Cadmium-induced alterations of the structural features of pectins in flax hypocotyl

In the course of our studies on the putative role of pectins in the control of cell growth, we have investigated the effect of cadmium on their composition, remodelling and distribution within the epidermis and fibre tissues of flax hypocotyl (Linum usitatissimum L.). Cadmium-stressed seedlings showed a significant inhibition of growth whereas the hypocotyl volume did not significantly change, due to the swelling of most tissues. The structural alterations consisted of significant increase of the thickness of all cell walls and the marked collapse of the sub-epidermal layer. The pectic epitopes recognized by the anti-PGA/RGI and JIM5 antibodies increased in the outer parts of the epidermis (external tangential wall and junctions) and fibres (primary wall and junctions). Concomitantly, there was a remarkable decrease of JIM7 antibody labelling and consequently an increase of the ratio JIM5/JIM7. Conversely, the ratio JIM7/JIM5 increased in the wall domains closest to the plasmalemma, which would expel the cadmium ions from the cytoplasm. The hydrolysis of cell walls revealed a cadmium-induced increase of uronic acid in the pectic matrix. Sequential extractions showed a remodelling of both homogalacturonan and rhamnogalacturonan I. In fractions enriched in primary walls, the main part of the pectins became cross-linked and could be extracted only with alkali. In fractions enriched in secondary walls, the homogalacturonan moieties were found more abundantly in the calcium-chelator extract while the rhamnogacturonan level increased in the boiling water extract.

Purification of several pectin methyltransferases from cell suspension cultures of flax (Linum usitatissimum L.)

Three pectin methyltransferases (PMT5, PMT7, PMT18; EC 2.1.1.6.x) were solubilized from the endo-membrane complex of flax cells, with 0.05% Triton X-100. After a 3 step-chromatography procedure, PMT7 and PMT5 were purified to apparent homogeneity. PMT5 and PMT7 differed regarding their optimum pH (5 or 7), the methyl acceptor (low or highly methylesterified pectin), their focusing pH range (6-7 or 8-9) and relative molecular mass (40 +/- 5 or 110 +/- 10 kDa). SDS-PAGE of PMT5 and PMT7 did not reveal bands at 40 or 110 kDa but only a silver stained band of about 18 kDa. Two independent methods (photo labelling and enzymatic activity) showed that this silverstained band corresponded to a methyltransferase with affinity for pectins. This polypeptide was of the same size as the enzyme designed PMT18 (18 +/- 3 kDa; pl 4-4.5) recovered during size exclusion chromatography of either PMT7 or PMT5, suggesting that PMT18 bears the catalytic site of PMT5 and PMT7.

First worldwide clinical experience with a new dual chamber implantable cardioverter defibrillator. Advantages and complications. The Ventak AV II DR investigators

AIMS

The need for physiological pacing and for improving the ability to discriminate atrial from ventricular tachyarrhythmias has prompted the development of dual chamber implantable cardioverter/defibrillators (ICDs).

METHODS

Fifty-two patients were implanted with a newly developed dual-chamber ICD providing rate-responsive physiological pacing (Ventak AV II DR). The device possesses two new arrhythmia detection algorithms ('atrial fibrillation rate threshold' and 'ventricular to atrial rate relationship') in addition to commonly used features such as 'onset' and 'stability'. During implantation, the atrial and ventricular lead impedances and pacing thresholds were determined together with the defibrillation threshold. Prior to discharge, attempts were made to induce both atrial and ventricular tachyarrhythmias in order to test those new detection criteria. All patients were followed for at least 3 months.

RESULTS

The device was successfully implanted in all 52 patients. Placement of the atrial lead was successful in 50/52 patients (96%; P-wave 3.2 +/- 1.4 mV; impedance 576 +/- 123 omega; atrial pacing threshold 1.2 +/- 0.9 V). Prior to discharge, 32 episodes of atrial fibrillation (AF) alone, 38 episodes of AF with ventricular fibrillation and 10 episodes of AF with monomorphic ventricular tachycardia were induced in 33/50 patients (66%) and all were appropriately classified by the detection algorithm. During the 3 months follow-up, 12 patients (23%) had appropriate and successful therapies for ventricular arrhythmias, while four patients (8%) experienced inappropriate ICD therapies. Although all these episodes were detected correctly as supraventricular arrhythmias by the device, therapy was delivered because of incorrect or incomplete programming. In all cases reprogramming of the device resolved the problem.

CONCLUSION

Implantation of dual chamber ICDs is feasible and appears to improve discrimination of supraventricular from ventricular tachyarrhythmias. In addition, patients with tachyarrhythmias and concomitant bradyarrhythmias may benefit from simultaneous physiological pacing. However, implantation and follow-up of such patients should be performed at experienced centres since both surgical handling and programming of these devices is more difficult and complex than conventional ICDs.

Managing atrial tachyarrhythmias in patients with implantable cardioverter defibrillators

The implantable cardioverter defibrillator (ICD) is accepted as the therapy of choice in preventing sudden cardiac death. Multiple studies, such as Antiarrhythmics Versus Implantable Defibrillators (AVID), the Canadian Implantable Defibrillator Study (CIDS), the Cardiac Arrest Study Hamburg (CASH), and the Multicenter Automatic Defibrillator Implantation Trial (MADIT), have shown a substantial benefit in survival rates for patients treated with ICDs compared with antiarrhythmic drug treatment. The detection of spontaneous ventricular tachycardias (VT) is based primarily on the programmed heart rate for intervention of the device. Supraventricular tachycardias (SVTs) cause unnecessary therapy delivery in about 10-20% of patients with ICDs. ICD therapy needs to be improved to become more specific for VT detection, by implementing algorithms that discriminate between VTs and SVTs. The enhanced detection criteria in currently available ICD devices are able to decrease the rate of unnecessary therapy to < 5% of patients. Atrial tachyarrhythmias can be managed with programmable features of the device, antiarrhythmic drug treatment, and in rare cases, ablation procedures. Dual-chamber ICDs, requiring an additional atrial lead, are indicated in specific situations of slow VT and concurrent, continuous SVTs at very similar heart rates. Using all these options, SVTs can be managed to achieve an acceptably low incidence of unnecessary therapy delivery in < 5% of ICD patients.

Short- and long-term performance of a tripolar down-sized single lead for implantable cardioverter defibrillator treatment: a randomized prospective European multicenter study. European Endotak DSP Investigator Group

A new, thinner (10 Fr) and more flexible, single-pass transvenous endocardial ICD lead, Endotak DSP, was compared with a conventional lead, Endotak C, as a control in a prospective randomized multicenter study in combination with a nonactive can ICD. A total of 123 patients were enrolled, 55 of whom received a down-sized DSP lead. Lead-alone configuration was successfully implanted in 95% of the DSP patients vs 88% in the control group. The mean defibrillation threshold (DFT) was determined by means of a step-down protocol, and was identical in the two groups, 10.5 +/- 4.8 J in the DSP group versus 10.5 +/- 4.8 J in the control group. At implantation, the DSP mean pacing threshold was lower, 0.51 +/- 0.18 V versus 0.62 +/- 0.35 V (p < 0.05) in the control group, and the mean pacing impedance higher, 594 +/- 110 omega vs 523 +/- 135 omega (p < 0.05). During the follow-up period, the statistically significant difference in thresholds disappeared, while the difference in impedance remained. Tachyarrhythmia treatment by shock or antitachycardia pacing (ATP) was delivered in 53% and 41%, respectively, of the patients with a 100% success rate. In the DSP group, all 28 episodes of polymorphic ventricular tachycardia or ventricular fibrillation were converted by the first shock as compared to 57 of 69 episodes (83%) in the control group (p < 0.05). Monomorphic ventricular tachycardias were terminated by ATP alone in 96% versus 94%. Lead related problems were minor and observed in 5% and 7%, respectively. In summary, both leads were safe and efficacious in the detection and treatment of ventricular tachyarrhythmias. There were no differences between the DSP and control groups regarding short- or long-term lead related complications.

Empirical versus tested antitachycardia pacing in implantable cardioverter defibrillators: a prospective study including 200 patients

BACKGROUND

Implantable cardioverter-defibrillators (ICDs) reduce the risk of sudden cardiac death. The objective of this study was to evaluate whether testing of antitachycardia pacing (ATP) for induced ventricular tachycardias (VTs) at predischarge examination can predict ATP success during follow-up.

METHODS AND RESULTS

The study covers 200 consecutive patients who received ICD implants from June 1991 through December 1995. All underwent electrophysiological testing. In 54 patients (ATP tested, group T), ATP terminated induced VTs successfully. In 146 patients (empirically programmed ATP, group E), only ventricular fibrillation could be induced, including 18 with unsuccessful ATP attempts for induced VTs. Disregarding the results of ATP testing, the same ATP scheme was programmed in all patients: three attempts of autodecremental ramp with 81% of the VT cycle length, with 8 to 10 pulses. During a follow-up of 20.4 +/- 10 months, 95% of 3819 spontaneous VTs were successfully terminated with ATP in 42 patients of group T. In group E, 90% of 1346 spontaneous VTs in 81 patients were terminated with ATP. Acceleration after ATP occurred in 2% in group T versus 5% in group E. The success for all episodes in individual patients was > or =90% in >60% of the ATP tested and empirically programmed patients.

CONCLUSIONS

The results of this 200-patient prospective study comparing tested versus empirical ATP show high success (95% versus 90%) for VT termination, with low rates of acceleration. ATP is safe and very effective and should be programmed "on" in all patients regardless of the predischarge EP inducibility.

Standardized assessment of psychological well-being and quality-of-life in patients with implanted defibrillators

The ICD has become a standard treatment for patients with malignant arrhythmias. Despite its benefits it may cause additional discomfort to the patients. Thus, quality-of-life needs to be assessed in these patients. Previous studies have used only small samples or unstandardized measures of quality-of-life that do not allow comparisons with other patient groups. The present study used standardized questionnaires for a cross-sectional assessment of psychological well-being and quality-of-life in ICD patients and to compare them to a similar group of coronary artery disease (CAD) patients without ICD. Overall, quality-of-life did not differ between both groups, ICD patients being less anxious than the CAD group. With increasing numbers of ICD shocks, however, the percentage of psychologically distressed ICD patients rose from 10% to > 50%. Psychologically distressed patients had significantly worse scores on most of the quality-of-life subscales, showed less treatment satisfaction, and more negative attitudes. It is concluded that ICD patients have an acceptable mean quality-of-life and low mean anxiety. However, a relevant subgroup of about 15%, especially patients with frequent shocks, experience psychological distress and reduced quality-of-life and should receive special care.

Enhanced detection criteria in implantable cardioverter-defibrillators to avoid inappropriate therapy

The aim of this prospective study was to evaluate the efficacy and safety of enhanced detection criteria, stability and sudden onset, for ventricular tachycardia (VT) in the therapy of implantable cardioverter-defibrillators (ICDs). These detection enhancements ensure a high specificity in detecting VT, thereby avoiding inappropriate therapy delivery due to supraventricular tachycardia. However, delayed sensing or even undersensing of VT may lead to a problematic, even fatal, outcome. In our study, the stability detection enhancement was programmed to discriminate atrial fibrillation (AF) in 84 of 124 patients with implanted ICDs and the sudden-onset detection enhancement in 47 of the 124 patients to discriminate sinus tachycardia. Using these enhancements in 124 patients with third-generation ICDs, 13 patients (11%) had inappropriate therapy during 20 months of follow-up. AF caused shock delivery in 6 patients (5%) and antitachycardia pacing in 4 patients, atrial flutter triggered shock therapy in 1 patient, and sinus tachycardia caused shock delivery in 2 patients. In 3 of the 13 patients inappropriate therapy recurred despite reprogramming the detection enhancements. The stability parameter of 241 spontaneous VT episodes as measured by the devices was 8 +/- 7 msec. Only 10 (4%) VTs had a stability parameter >25 msec. In 46 patients a combination of both detection enhancements, stability and/or sudden onset, were programmed. The use of detection enhancements proved safe and no patient had suffered negative side effects due to prolonged detection time or therapy delay. Inappropriate shock delivery due to AF, a major complication in ICD therapy, was reduced to 5% of patients. The use of the stability enhancement is recommended for patients with intermittent or chronic AF. Selected patients profit from programming both the stability and sudden onset criteria.

Implantable cardioverter defibrillator detection during radiofrequency catheter ablation of ventricular tachycardia

Right ventricular radiofrequency catheter ablation was performed in an ICD patient with frequent ventricular tachycardia without prior inactivation of the device. The registrations of intracardiac ECG and marker channel were excellent during energy delivery: the surface ECG was affected. The device did not show dysfunction during and after energy delivery.

Obstructive sleep apnoea and signal averaged electrocardiogram

Patients with obstructive sleep apnoea demonstrate an increased rate of ventricular arrhythmias. The present study was designed in order to investigate whether these arrhythmias may be related to myocardial injury, since myocardial injury of various aetiologies has been observed to change the signal averaged electrocardiogram (ECG). Signal averaged ECG was registered in 23 patients with obstructive sleep apnoea diagnosed by polysomnography (apnoea index 43 +/- 20 events.h-1, age 55 +/- 10 yrs). QRS duration, root mean square voltage of the last 40 ms of QRS, and low amplitude (< 40 mV) signal duration were determined from the vector magnitude of the QRS, high-pass filtered at 40 Hz. Patients with coronary heart disease or bundle branch block were excluded. No patient showed an abnormal signal averaged ECG. Mean duration of the filtered QRS complex was 96 +/- 9 ms, root mean square voltage 38 +/- 18 microV and low amplitude signal duration 26 +/- 8 ms. These results were not significantly different from 14 snoring subjects with an apnoea/hypopnoea index < 10. Four patients showed no ventricular arrhythmias and six patients had Lown III or IVa in the Holter ECG. Echocardiography revealed increased left atrial (43.7 +/- 4.1 mm) and interventricular septal diameters (11.3 +/- 1.4 mm). In conclusion, obstructive sleep apnoea does not generate a substrate for late potentials in the signal averaged ECG.

Obstructive sleep apnoea and signal averaged electrocardiogram

Patients with obstructive sleep apnoea demonstrate an increased rate of ventricular arrhythmias. The present study was designed in order to investigate whether these arrhythmias may be related to myocardial injury, since myocardial injury of various aetiologies has been observed to change the signal averaged electrocardiogram (ECG). Signal averaged ECG was registered in 23 patients with obstructive sleep apnoea diagnosed by polysomnography (apnoea index 43 +/- 20 events.h-1, age 55 +/- 10 yrs). QRS duration, root mean square voltage of the last 40 ms of QRS, and low amplitude (< 40 mV) signal duration were determined from the vector magnitude of the QRS, high-pass filtered at 40 Hz. Patients with coronary heart disease or bundle branch block were excluded. No patient showed an abnormal signal averaged ECG. Mean duration of the filtered QRS complex was 96 +/- 9 ms, root mean square voltage 38 +/- 18 microV and low amplitude signal duration 26 +/- 8 ms. These results were not significantly different from 14 snoring subjects with an apnoea/hypopnoea index < 10. Four patients showed no ventricular arrhythmias and six patients had Lown III or IVa in the Holter ECG. Echocardiography revealed increased left atrial (43.7 +/- 4.1 mm) and interventricular septal diameters (11.3 +/- 1.4 mm). In conclusion, obstructive sleep apnoea does not generate a substrate for late potentials in the signal averaged ECG.

Catheter ablation of ventricular tachycardia in 136 patients with coronary artery disease: results and long-term follow-up

OBJECTIVES

This study attempted to determine the feasibility and long-term efficacy of catheter ablation by means of either radiofrequency or direct current energy in a selected group of patients with coronary artery disease.

BACKGROUND

Catheter ablation of ventricular tachycardia has proved to be highly effective in patients with idiopathic and bundle branch reentrant ventricular tachycardia. In patients with coronary artery disease and recurrent sustained ventricular tachycardia resistant to medical antiarrhythmic management, the value of catheter ablation has not yet been established.

METHODS

One hundred thirty-six patients with coronary artery disease and one configuration of monomorphic sustained ventricular tachycardia underwent radiofrequency (72 patients) or direct current catheter ablation (64 patients). The mapping procedure to localize an adequate site for ablation included pace mapping during sinus rhythm, endocardial activation mapping, identification of isolated mid-diastolic potentials and pacing interventions during ventricular tachycardia.

RESULTS

Primary success was achieved in 102 (75%) of 136 patients (74% of 72 undergoing radiofrequency and 77% of 64 with direct current ablation). Complications were noted in 12% of patients. During a mean (+/- SD) follow-up period of 24 +/- 13 months (range 3 to 68), ventricular tachycardia recurred in 16% of patients.

CONCLUSIONS

Catheter ablation of ventricular tachycardia in coronary artery disease is feasible in patients with one configuration of monomorphic sustained ventricular tachycardia. There is no significant difference with respect to the type of energy applied. The follow-up data show that in a selected group of patients with coronary artery disease, catheter ablation offers a therapy alternative.

Management of patients after catheter ablation of ventricular tachycardia

The management of patients after catheter ablation of ventricular tachycardia is not well defined. In this article we summarize recently published results and report our own experience. Factors influencing the clinical outcome of these patients and methods to identify patients with an increased risk of recurrence of ventricular tachycardia are discussed. Furthermore, a review is given on current concomitant therapeutic tools including antiarrhythmic drugs and the implantation of an automatic cardioverter defibrillator.

[Ventricular macro-reentry tachycardia of the bundle branch type--indications for catheter ablation]

Out of 115 patients with recurrent sustained monomorphic ventricular tachycardia who underwent catheter ablation between August, 1987 and May, 1992, 7 were found to have bundle branch reentry. Bundle branch reentrant tachycardia was assumed if His potential or bundle branch potential preceded ventricular activation during tachycardia with identical H-H'- and V-V'-intervals. In 5 patients, catheter ablation of the right bundle branch and in 2 patients, ablation of the proximal left bundle branch were performed with direct current or radiofrequency energy. The procedure was successful in all 7 patients. During the follow-up of 15 +/- 12 months, 3 patients died due to cardiac failure. One patient had sustained ventricular tachycardia 12 months after catheter ablation which was not due to bundle branch reentry and was treated with an implantable cardioverter/defibrillator. Atrioventricular conduction delay in the surface electrogram and during electrophysiologic study may give a hint at bundle branch reentrant ventricular tachycardia since it was seen in 5 of our 7 patients. Catheter ablation of one bundle branch is an effective treatment which can prevent recurrence of this tachycardia.