Bipolar Transvenous Defibrillation: Efficacy of Two Different Positions of the Anode

For most nonthoracotomy defibrillotion lead systems, the transvenous anode can be positioned independently of the right ventricular (RV) cathode. Usually a vertical position in the superior vena cava (SVC) is chosen. However, it is unknown if this position yields the optimal defibrillation threshold (DFT). There-fort, in 15 patients undergoing defibrillator implantation the SVC position was compared in a crossover study design with a horizontal position in the left brachiocephalic vein (BCV). Mean DFT was not different for SVC and BCV (19.2 ± 9.6) vs 18.5 ± 9.1 J) but DFT of individual patients differed by up to 12 joules. A positive correlation between impedance and DFT in the BCV position (r = 0.6; P ≤ 0.05) indicated that the improved geometry of the defibrillation field with the BCV position is opposed by a higher impedance found for this position (63 ± 15 Ω vs 52 ± 7 Ω). Thus, defibrillation is not improved in general although individual patients might benefit.     

Long‐Term Outcome of Patients with Severe Biventricular Heart Failure and Severe Mitral Regurgitation After Percutaneous Edge‐to‐Edge Mitral Valve Repair

Objective

To assess long‐term outcome and parameters associated with poor and favorable outcome in patients with a left ventricular ejection fraction (LV‐EF) ≤25% and severe mitral regurgitation (MR) after percutaneous edge‐to‐edge mitral valve repair (pMVR).

Background

There is no data on long‐term outcome in this cohort of patients.

Methods

We analyzed all 34 patients with a LV‐EF ≤25% and severe MR treated with pMVR in 2 university hospitals from 2009 to 2012.

Results

Mitral regurgitation could be successfully reduced to grade ≤2 in 30 patients (88%). Long‐term follow‐up (up to 5 years) revealed a steep decline of the survival curve reaching 50% already 8 month after pMVR. In contrast, estimated survival of the remaining patients showed a favorable long‐term outcome. Patients deceased during the first year presented with higher right ventricular tricuspid pressure gradient (RVTG) (44.5 ± 8.4 mmHg vs. 35.2 ± 15.4 mmHg, P = 0.035) and worse RV‐function (P = 0.014) prior to the procedure. One‐year mortality of patients with pulmonary hypertension and depressed RV‐function (n = 22) was very high (77%) compared to the remaining patients (n = 12, mortality rate of 0%, P = 0.0001).

Conclusions

Although pMVR lead to a successful reduction of MR in patients with a LV‐EF ≤25%, 1‐year mortality in this cohort was very high. However, a subgroup of patients showed a favorable long‐term outcome after pMVR. Especially the right ventricular parameters sustained RV‐function and absence of pulmonary hypertension—easily assessed with echocardiography—might be used to identify this subgroup and encourage pMVR in these patients.

     

How Can We Identify the Best Implantation Site for an ECG Event Recorder?

ZELLERHOFF, C., et al. : How Can We Identify the Best Implantation Site for an ECG Event Recorder? The aim of this study was to show how to find the preferable implantation site for an ECG event recorder (ECG‐ER). We compared the quality of bipolar ECG recordings (4‐cm electrode distance, vertical position) in 65 patients at the following sites: left and right subclavicular, left and right anterior axillary line (4th‐5th interspace), left and right of the sternum (4th‐5th interspace), heart apex, and subxyphoidal. The results were compared to the standard ECG lead II. In 30 patients, an additional comparison between vertical and horizontal ECG registrations was done using the same sites. ECG signals in five patients were compared positioning the electrodes towards the skin with turning them towards the muscle during ECG‐ER implantation. The best ECG quality (defined as highest QRS amplitude, best visible P wave and/or pacemaker spike, best measurable QRS duration, and QT interval) and best agreement with the standard lead II was found in 68% on the left of the sternum, significantly less often (P < 0.001 ) on the right of the sternum (14.1%), left subclavicular (6.9%), apical (5.5%) and subxyphoidal (4.2%). A significantly higher QRS amplitude was measured and the P wave was more often visible in the vertical electrode position than in the horizontal position. In all five ECG‐ER patients, there was a good agreement between the bipolar surface ECG at the implantation site and ECG‐ER stored signals. A significant noise signal occurred in all five patients when the ECG‐ER was implanted with electrodes towards the muscle. A P wave was visible in only three of those patients, but there was an insignificantly higher QRS amplitude than in ECG‐ERs implanted with electrodes towards the skin. From these results, it can be concluded that the best implantation site for an ECG‐ER is right or left of the sternum, positioning the electrodes vertically and towards the skin.     

Improved Sensing Signals After Endocardial Defibrillation with a Redesigned Integrated Sense Pace Defibrillation Lead

Adequate sensing is a basic requirement for appropriate therapy with ICDs. Integrated sense pace defibrillation leads, which facilitate ICD implantation, show a close proximity of sensing and defibrillation electrodes that might affect the sensing signal amplitude by the high currents of internal defibrillation. In 99 patients, we retrospectively examined two integrated sense pace defibrillation leads, eitherboth with a distance of 6 mm between the tip of the lead (sensing cathode) and the right ventricular defibrillation electrode (sensing anode) or one with a distance of 12 mm. Three seconds after a shock of 20 J, mean sensing signal amplitude during sinus rhythm (SR) decreased from 10.5 ± 4.3 mVto 5.1 ± 3.7 mV (P < 0.001) for the 6-mm lead, but showed no significant decrease for the 12-mm lead. The degree of signal reduction was inversely related to the time passed since defibrillation. Significant differences in reduction of sensing signal amplitude concerning monophasic and biphasic shocks could not be observed. Mean sensing signal amplitude of VF after shocks that failed to terminate it decreased in the same order as during SR (from 8.3 ± 4.1 mV to 4.1 ± 3.2 mV), but resulted in no failure of redetection during ongoing VF. DFTs did not differ for the 6-mm and the 12-mm lead. In conclusion, close proximity of the right ventricular defibrillation coil to the sensing tip of an integrated sense pace defibrillation lead causes energy and time related reductions in sensing signal amplitude after defibrillation, and might cause undersensing in the postshock period. A new lead design with a more proximal position of the right ventricular defibrillation coil avoids these problems without impairing DFTs.     

Biphasic Defibrillation Using a Single Capacitor with Large Capacitance: Reduction of Peak Voltages and ICD Device Size

The volume of current implantable cardioverter defibrillators (ICD) is not convenient for pectoral implantation. One way to reduce the size of the pulse generator is to find a more effective defibrillation pulse waveform generated from smaller volume capacitors. In a prospective randomized crossover study we compared the step-down defibrillation threshold (DFT) of a standard biphasic waveform (STD), delivered by two 250-μF capacitors connected in series with an 80% tilt, to an experimental biphasic waveform delivered by a single 450μF capacitor with a 60% tilt. The experimental waveform delivered the same energy with a lower peak voltage and a longer duration (LVLDj. Intraopera-tively, in 25 patients receiving endocardial (n = 12) or endocardial-subcutaneous array (n = 13) defibrillation leads, the DFT was determined for both waveforms. Energy requirements did not differ at DFT for the STD and LVLD waveforms with the low impedance (32 ± 4Ω) endocardial-subcutaneous array defibrillation lead system (6.4 ± 4.4 J and 5.9 ± 4.2 J, respectively) or increased slightly (P - 0.06) with the higher impedance (42 ± 4 Ω) endocardial lead system (10.4 ± 4.6 J and 12.7 ± 5.7 /. respectively), However, the voltage needed at DFT was one-third lower with the LVLD waveform than with the STD waveform for both lead systems (256 ± 85 V vs 154 ± 53 V and 348 ± 76 V vs 232 ± 54 V, respectively). Thus, a single capacitor with a large capacitance can generate a defibrillation pulse with a substantial lower peak voltage requirement without significantly increasing the energy requirements. The volume reduction in using a single capacitor can decrease ICD device size.     

Case Report: Vulvar Lichen Sclerosus in a Premenarchal Girl with a Complicated Biopsy

Abstract:  Lichen sclerosus is a T-lymphocyte mediated chronic cutaneous disorder with predilection for the vulva. In prepubertal girls, lichen sclerosus presents as vulvar discomfort, pruritus, bruising/bleeding, discharge, dysuria, or painful defecation. Diagnosis and treatment of lichen sclerosus is of utmost importance in the prevention of complications such as scarring, adhesions, atrophy, or long-term sexual dysfunction. We discuss a case of a 4-year-old female with an atypical presentation of genital lichen sclerosus and a complicated biopsy.     

Standard procedures for adults in accredited sleep medicine centres in Europe

The present paper describes standardized procedures within clinical sleep medicine. As such, it is a continuation of the previously published European guidelines for the accreditation of sleep medicine centres and European guidelines for the certification of professionals in sleep medicine, aimed at creating standards of practice in European sleep medicine. It is also part of a broader action plan of the European Sleep Research Society, including the process of accreditation of sleep medicine centres and certification of sleep medicine experts, as well as publishing the Catalogue of Knowledge and Skills for sleep medicine experts (physicians, non-medical health care providers, nurses and technologists), which will be a basis for the development of relevant educational curricula. In the current paper, the standard operational procedures sleep medicine centres regarding the diagnostic and therapeutic management of patients evaluated at sleep medicine centres, accredited according to the European Guidelines, are based primarily on prevailing evidence-based medicine principles. In addition, parts of the standard operational procedures are based on a formalized consensus procedure applied by a group of Sleep Medicine Experts from the European National Sleep Societies. The final recommendations for standard operational procedures are categorized either as 'standard practice', 'procedure that could be useful', 'procedure that is not useful' or 'procedure with insufficient information available'. Standard operational procedures described here include both subjective and objective testing, as well as recommendations for follow-up visits and for ensuring patients' safety in sleep medicine. The overall goal of the actual standard operational procedures is to further develop excellence in the practice and quality assurance of sleep medicine in Europe.     

Proton n.m.r. investigation of conformational influence of penicillamine residues on the disulfide ring system of opioid receptor selective Somatostatin derivatives

Three cyclic disulfide analogs related to somatostatin, d -Phe¹ -Cys²-Tyr³-d -Trp⁴-Lys⁵-Thr⁶-Xxx⁷-Thr⁸NH₂ (where Xxx =l -Pen 1; l -Cys 3; or d -Pen 4) were examined in DMSO-d₆ by one- and two-dimensional proton n.m.r. spectroscopy in order to analyze the conformational influence of the position-7 residue on the 20-membered disulfide ring. From these studies it was concluded that all three analogs maintain a β II turn solution conformation for the core tetrapeptide-Tyr³-d -Trp⁴-Lys⁵-Thr⁶-. However, the disulfide conformation differs in the analogs, with 1 and 3 having a left-handed and 4 a right-handed disulfide chirality.     

Expression of an α-cardiac like myosin heavy chain in diaphragm,chronically stimulated,and denervated fast-twitch muscles of rabbit

An additional slow fibre type, type I, is detected in diaphragm and appears in fast-twitch hindlimb muscles of rabbit under the influence of altered neuromuscular activity. Type I fibres were delineated from fibres expressing myosin heavy chain I (type I) by immunohistochemistry with a monoclonal antibody raised against the -cardiac MHCI. When stained for mATPase after acid and alkaline preincubations, some type I fibres resembled type I and type IIA fibres, respectively. Some type I fibres displayed dissimilar mATPase staining, indicating heterogeneity of this fibre population. The appearance of numerous type I fibres in stimulated muscles, which in addition contain type IIA and type I fibres, suggested that they may be interspaced between types IIA and I. Electrophoresis under nondenaturing conditions disclosed an additional isomyosin both in normal diaphragm and stimulated muscles. This band displayed the same mobility as the slowest isomyosin in rabbit masseter muscle. It was recognized by the same monoclonal (anti-- cardiac MHC) antibody used for immunohistochemistry. Therefore, this isomyosin appeared to be very similar, but perhaps not identical to the -cardiac MHC-based isomyosin, probably resulting from discrete differences in the MHC complement. This assumption agrees with additional findings suggesting an even greater heterogeneity of the MHCs than generally assumed. In support of this, we show in atrium and masseter muscles the existence of an additional, electrophoretically distinct MHC isoform which migrates in close vicinity to MHCI