Multiphasic disseminated encephalomyelitis associated with streptococcal infection

Multiphasic disseminated encephalomyelitis (MDEM) is a rare peculiar diagnosis which is defined as acute demyelinating central nervous system disease with relapses occurring only within 4 weeks of initial manifestation. This report describes the case of a 6-year-old boy with MDEM diagnosed by clinical findings and magnetic resonance imaging. The disease had a biphasic evolution, and with a second course of high-dose corticosteroids a complete recovery without further relapse was obtained during the following 18 months. Serological evidence of streptococcal infection as specific trigger for MDEM was given. Thus this report raises the question whether an additional penicillin prophylaxis could be valuable for prevention of streptococcus-associated MDEM relapses.     

Linear Ablation with Duty‐Cycled Radiofrequency Energy at the Cavotricuspid Isthmus

Background: Multielectrode catheters using duty‐cycled radiofrequency (RF) have been developed to treat atrial fibrillation (AF). Many of these patients also have atrial flutter. Therefore, a linear multielectrode has been developed using the same RF energy. Objective: The concept and acute results of linear ablation using duty‐cycled RF were tested in the cavotricuspid isthmus (CTI). Methods: The CTI was targeted in 75 patients, in 68 (90%) among them as an adjunct to AF ablation with the same technology. A linear electrode catheter with a 4‐mm tip and five 2‐mm ring electrodes was connected to a generator titrating duty‐cycled RF at 20–45 W up to a target temperature of 70°C in 1:1 unipolar/bipolar mode. Results: During a mean procedure time of 20 ± 12 minutes, complete CTI block was achieved by 4 ± 3 applications of duty‐cycled RF in 69 (92%) patients. No more than three RF applications were necessary in 60% of patients. During the initial learning curve, standard RF had to be used in five (7%) patients. Complete block was not achieved in one patient with frequent episodes of AF. Char was observed in five (7%) patients with poor electrode cooling; consequently, the temperature ramp‐up was slowed and manually turned off in the event of low‐power delivery. Two groin hematomas occurred; otherwise, no clinical complications were observed. Conclusion: Multielectrode catheters delivering duty‐cycled RF can effectively ablate the CTI with few RF applications with promising acute results. Further modifications are necessary to improve catheter steering and prevent char formation. (PACE 2010; 444–450)     

Polarity Reversal Improves Defibrillation Efficacy in Patients Undergoing Transvenous Cardioverter Defibrillator Implantation with Biphasic Sbocks

The purpose of this study was to determine the influence of polarity reversal on DFT in patients undergoing implantation of nonthoracotomy defibrillators with biphasic shocks. Previous studies have shown higher defibrillation efficacy with using the distal electrode as anode in implantation of nonthoracotomy defibrillators and monophasic shocks. However, it is as yet unclear whether biphasic shock defibrillation will also be influenced by polarity reversal. Using a transvenous lead system with a proximal electrode in the superior caval vein and a distal electrode in the RV apex, 27 patients undergoing defibrillator implantation were randomized to DFT testing with "initial" (distal electrode = cathode) or "reversed" polarity (distal electrode = anode). Defibrillation energy was reduced stepwise until defibrillation failure occurred. At this point, polarity was switched and testing continued until the lowest energy requirement was determined for both polarities. With reversed polarity, DFT was 11.1 ± 5.7 J versus 13.3 ± 5.8 J with initial polarity (P = 0.033). This means a 17% reduction of the DFT. In 10 patients, the threshold was lower with reversed, whereas in 3 patients it was lower with initial polarity. In conclusion, changing electrode polarity in transvenous implantable defibrillators with biphasic shocks may significantly influence defibrillation energy requirements. Therefore, polarity reversal should always be attempted before considering patch implantation.     

Preexcitation in Hypertrophic Cardiomyopathy: A Case of a Fasciculoventricular Mahaim Fiber

STELLBRINK, C., et al .: Preexcitation in Hypertrophic Cardiomyopathy: A Case of a Fasciculoventricular Mahaim Fiber . A patient with hypertrophic cardiomyopathy (HCM) who presented with preexcitation pattern on the surface ECG suggestive of the Wolff-Parkinson-White (WPW) syndrome is described. Intracardiac electrophysiological study revealed a fixed anomalous QRS complex and a short fixed His-ventricular interval indicating a fasciculoventricular Mahaim fiber. As this specific form of accessory connection does not cause reentrant tachycardias, no treatment was required. It is important to distinguish this entity from atriofascicular or nodoventricular Mahaim fibers or the WPW syndrome in patients with HCM showing a preexcitation pattern in the surface ECG, as these may cause life-threatening arrhythmias in this patient population.     

Pacemaker Therapy in Premature Children with High Degree AV Block

The smallest pacemaker pulse generator and a steroid-eluting bipolar epicardial lead were implanted in two premature children with symptomatic AV block. Stable capture threshold and high amplitude evoked response electrogram resulted in normal function of the pacemaker Autocapture algorithm, which adjusts output 0.3 V above the measured capture threshold. Autocapture hud previously been used only with endocardial leads. Longer-term observation is required.     

Influence of Body Position on Defibrillation Thresholds of Nonthoracotomy Implantable Defibrillators:

DFT of Nonthoracotomy Defibrillators. Introduction : Defibrillation thresholds (DFTs) usually are determined with the patient in the supine position. However, patients may be in the upright position when a shock is delivered during follow-up, which may explain some first shock failures observed clinically. This study investigated whether body posture affects defibrillation energy requirements of nonthoracotomy implantable cardioverter defibrillators with biphasic shocks.
Methods and Results : Using a step up-down protocol, DFTs were compared intraindividually in 52 patients ("active-can" systems in 41 patients, two-lead systems in II patients) for the supine and upright positions as achieved by a tilt table. The mean DFT was 7.3 ± 4.2 J in the supine versus 9.2 ± 4.8 J in the upright position (P = 0.002). Repeated comparison in reversed order 3 months after implantation in 22 patients revealed thresholds of 6.2 ± 2.5 J (supine) versus 8.4 ± 3.7 J (upright; P < 0.03) 1 week and 4.4 ± 2.4 J (supine) versus 6.2 ± 4.1 J (upright; P < 0.04) 3 months after implantation. DFTs decreased significantly for both body positions from 1 week to 3 months after implantation (P < 0.04).
Conclusion :(I) DFTs for biphasic shocks delivered by nonthoracotomy defibrillators are higher in the upright compared to the supine body position. (2) Differences remain significant 3 months after implantation. For both body positions, DFT decreases significantly from 1 week to 3 months after implantation. These findings have important implications for programming first shock energy to lower than maximal values or for development of devices with lower maximal stored energy.     

The Duct-Occlud Device for Closure of Patent Ductus Arteriosus

The Duct-Occlud device is a coil-type device designed to occlude small-to-moderate patent ductus arteriosus. The design of the device, its delivery system, and the implant procedure are described, and the experimental and clinical experiences accumulated utilizing the device for occlusion of patent ductus arteriosus are reviewed.     

Hepatitis C viral kinetics

Abstract   Standard therapy with (pegylated) interferon-alfa and ribavirin still leads to sustained virologic response rates of 50–60%, only. Therefore, new therapeutic strategies are required. With the analysis of mathematical models of hepatitis C viral kinetics, individual kinetic rates as infected cell loss, clearance of free virus, and an efficiency factor on blocking viral production can be estimated. They can be used to summarize and quantify the initial response to antiviral therapy and, furthermore, allow the assessment of treatment mechanisms, prediction of treatment response, and the efficient identification of viral and host factors on treatment response. They may even be used for optimizing and individualizing therapy.     

Semi‐elective intraosseous infusion after failed intravenous access in pediatric anesthesia1

Background: Intraosseous (IO) infusion is a well‐established intervention to obtain vascular access in pediatric emergency medicine but is rarely used in routine pediatric anesthesia. Methods: In this observational study, we report on a series of 14 children in whom semi‐elective IO infusion was performed under inhalational anesthesia after peripheral intravenous (IV) access had failed. Patient and case characteristics, technical details, and estimated timings of IO infusion as well as associated complications were reviewed. Data are median and range. Results: IO infusion was successfully established in fourteen children [age: 0.1–6.00 years (median 0.72 years); weight: 3.5–12.0 kg (median 7.0 kg)]. The majority suffered from chronic cardiac, metabolic, or dysmorphic abnormalities. Estimated time taken from inhalational induction of anesthesia until insertion of an intraosseous needle was 26.5 min (15–65 min). The proximal tibia was cannulated in all patients. The automated EZIO? IO system was used in eight patients and the manual COOK? system in six patients. Drugs administered included hypnotics, opioids, neuromuscular blocking agents and reversals, cardiovascular drugs, antibiotics, and IV fluids. The IO cannulas were removed either in the operating theatre (n = 5), in the recovery room (n = 5), or in the ward (n = 4), after 73 min (19–225 min) in situ. There were no significant complications except one accidental postoperative dislocation. Conclusions: IO access represents a quick and reliable alternative for pediatric patients with prolonged difficult or failed IV access after inhalational induction of anesthesia.     

Diagnostic Accuracy of Cardiac Magnetic Resonance Imaging in the Detection and Characterization of Left Atrial Catheter Ablation Lesions: A Multicenter Experience

MRI Detection of Left Atrial Ablation Lesions . Introduction: We tested the hypothesis that cardiovascular magnetic resonance (CMR) imaging can reliably distinguish the presence or absence of left atrial (LA) ablation lesions by blinded analysis of pre‐ and postablation imaging. Methods: Consecutive patients at 2 centers undergoing pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation by either wide area circumferential radiofrequency ablation (WACA) or ostial ablation with a cryoballoon underwent CMR late gadolinium enhancement (LGE) imaging pre‐ and 3 months postablation. Imaging was anonymized for blinded analysis of (1) LGE images, and (2) a 3D fusion image with LGE projected onto a segmented LA surface. Scans were categorized using both assessment techniques separately as pre‐ or postablation, and if postablation, whether lesions were in an ostial or WACA distribution. Results: LGE imaging was performed in 50 patients (aged 60 ± 10 years, 68% male, 24 underwent WACA and 26 had cryoablation). Sensitivity and specificity for detection of ablation lesions was 60% and 96% on LGE imaging. Sensitivity was higher using 3D fusion imaging (88%; P = 0.003). The proportion in whom lesions were both detected and the distribution correctly assessed as WACA or ostial was higher with 3D fusion imaging compared to LGE imaging (54% vs 28%; P = 0.014). There was no difference in the detection of radiofrequency ablation lesions compared to cryoablation lesions (58% vs 62%; P = 1.000). Conclusion: LGE imaging of atrial scar is not yet sufficiently accurate to reliably identify ablation lesions or to determine lesion distribution. (J Cardiovasc Electrophysiol, Vol. 24, pp. 396‐403, April 2013)