Percutaneous Pacemaker Lead-Transsecting Catheter

We describe the development and successful use of a percutaneous lead-transsection catheter. It was used in two patients in whom removal of chronically implanted atrial pacing leads could not be accomplished by traction.     

Rate Response During Submaximal Exercise: Comparison of Three Different Sensors

Since 1983, 248 rate responsive pacemakers were implanted at our hospital. The main emphasis during clinical follow-up has to be placed on (he adjustment and control of its rate adaption, to meet the requirements of the aged patient's daily life. Repeated submaximal exercise but not extreme strain, come to the fore. Kaltenbach's step test (individually by stencils defined normal ranges of the heart rate during a 6 minute submaximal exercise and a 6 minute recovery period; age and sex dependent work load relative to body surface area) is able to mimic everyday efforts in an easy and reliable way. Nineteen patients with QT-related pacemaker, 12 patients with respiratory dependent pacemaker and 45 patients with body activity directed pm Activitrax were exercised using Kaltenbach's step test (mean wattage QT: 56 ± 14, HDP: 75 ± 29, Activitrax: 64 ± 20). Fifty-two patients performed 3 rounds. In comparison, 42 patients with DDD-pm underwent the same test (75 ± 28 Watt). The average curve [heart rate] with QT-pm settled in the normal range of the step test but was distorted. Only 42% of the patients reached normal range in ail three rounds. The mean heart rate of the RDP-group bordered on the basis of the normal range. The average curve (heart rate) of patients with Activitvax or DDD settled exactly in the desirable range. Problems with the rate response under repeated exercise did not occur either in the RDP or in the DDD group. The rate response behavior of the QT-related pm, the RDP and the Activitrax was of different quality. The Activitrax, with all its limitations as a device witb a non physioiogical sensor, came off very well; even though modifications of the programmable gradings of the rate response (thresholds) should be considered. Kaltenbach's step test is an excellent method to adjust and control rate responsive pacemaker.     

TREATMENT OF INTERSTITIAL CYSTITIS: COMPARISON OF SUBTRIGONAL AND SUPRATRIGONAL CYSTECTOMY COMBINED WITH ORTHOTOPIC BLADDER SUBSTITUTION

Purpose

We retrospectively evaluate the outcome of interstitial cystitis treated with subtrigonal or supratrigonal cystectomy and orthotopic bladder substitution.

Materials and Methods

Of 22 women and 1 man a mean of 51 years old with interstitial cystitis refractory to conservative therapy 17 were treated with subtrigonal cystectomy and ureteral reimplantation (group 1), and 6 were treated with supratrigonal cystectomy directly above the ureteral orifices (group 2). Both groups underwent orthotopic bladder substitution with an ileocecal pouch (Mainz pouch I).

Results

Postoperatively functional capacity significantly increased from a mean plus or minus standard error of mean 46 +/− 5 to 346 +/− 57 ml. in group 1 and 34 +/− 61 to 319 +/− 29 ml. in group 2 (p <0.001). Daytime and nighttime urinary frequency significantly decreased from 24 +/− 2 to 8 +/− 1 and 7 +/− 1 to 2 +/− 1 ml., respectively, in group 1 and 28 +/− 2 to 6 +/− 1 to 1 +/− 1 ml., respectively, in group 2 (p <0.001). At a mean followup of 93.9 months 14 patients in group 1 (82%) are completely symptom-free, and 1 has tolerable residual urinary urgency and suprapubic pain. At a mean followup of 31.5 months all group 2 patients are symptom-free and void spontaneously, whereas 41% of the group 1 patients require self-catheterization after subtrigonal cystectomy.

Conclusions

For interstitial cystitis refractory to conservative treatment subtotal cystectomy with orthotopic bladder substitution with the ileocecal pouch (Mainz pouch I) is a valid therapeutic option. In this series supratrigonal and subtrigonal cystectomy resulted in similar relief of symptoms but the former appears to provide better functional bladder rehabilitation.     

Clinical Applicability of in vivo Reflectance Confocal Microscopy for the Diagnosis of Actinic Keratoses

BACKGROUND In vivo reflectance confocal microscopy (RCM) has been used for evaluation of the morphologic features of nonmelanoma skin cancer. The application of RCM for diagnosis of basal cell carcinoma has been reported; however, the evaluation of actinic keratoses (AKs) has only been the subject of preliminary studies.
STUDY GOAL The goal of this study was to evaluate the applicability of RCM in the diagnosis of AK in correlation with routine histology.
MATERIALS AND METHODS Forty-four Caucasians with a minimum of one AK participated in this study. Evaluation consisted of clinical examination, RCM, and routine histology, including a total of 46 AKs in the final analysis. Ten normal skin sites served as controls. RCM features of AK included parakeratosis, architectural disarray, and keratinocyte pleomorphism. Following blinded evaluations, sensitivity/specificity, kappa analysis, and Spearman's correlation were performed on all parameters.
RESULTS Sensitivity/specificity values of RCM features ranged from 80% to 98.6%. The presence of architectural disarray and cellular pleomorphism appeared to be the best predictor of AK.
CONCLUSION In summary, RCM may be a promising technology for the noninvasive detection of AK and as adjunct tool to clinical diagnosis and monitoring. However, the preliminary nature of this study warrants further investigations.     

Suppression of Atrial Tachyarrhythmias by Pacing

Pace‐Suppression of AF. Introduction: Treatment of atrial tachyarrhythmias (ATs) remains difficult in many patients. Accordingly, new therapeutic approaches for AT suppression are evaluated. Atrial pacing may prevent ATs by modifying the electrophysiologic conditions required for sustained ATs. Methods and Results: New pacing algorithms for prevention of AT are aimed at permanent overdrive suppression of arrhythmic activity, reduction of dispersion of atrial refractoriness produced by short‐long cycles, more aggressive overdrive pacing after spontaneous sinus conversion to prevent early reinitiation of ATs, and prevention of inadequate rate decay in patients with vagally induced ATs. AT prevention may be achieved by dedicated atrial pacing sites, e.g., pacing at the insertion of Bachmann's bundle or biatrial pacing, which compensates for interatrial conduction delay. Preexciting regions of critical conduction delay, pacing at the triangle of Koch or coronary sinus os, and dual‐site right atrial pacing have shown antiarrhythmic effects. Atrial preventive pacing and pharmacologic treatment may work synergistically in the concept of hybrid therapy. To prevent atrial electrical remodeling, early termination of AT seems desirable. This may be achieved by implanted devices that automatically detect ATs and provide atrial antitachycardia pacing for organized ATs. Initial studies showed that regular AT can automatically be terminated in approximately 50% of treated episodes. Conclusion: Pacing for prevention of AT and termination of organized AT episodes may become important steps within the concept of hybrid therapy of AT. However, their clinical efficacy and optimal patient selection remain to be evaluated in prospective, well‐designed clinical trials.     

Stereological estimation of the volume weighted mean volumes of alveoli and acinar pathways in the rat lung to characterise alterations after ischaemia/reperfusion

The aim of this study was to characterise pulmonary reimplantation injury in isolated, perfused rat lungs following 2 h of cold ischaemia, and 50 min. of in vitro reperfusion. The effects of 2 differently composed lung preservation solutions (low potassium Euro-Collins and Celsior; each n=5) were examined in comparison with untreated, nonischaemic control lungs (n=3). After fixation by vascular perfusion and tissue collection by systematic random sampling, the volume weighted mean volume (_v) of alveoli and acinar pathways was estimated by light microscopic stereology using the method of point sampled intercepts in plastic embedded, Azan-stained material. Significantly higher _v of alveoli and acinar paths was found in the Celsior group than in Euro-Collins preserved lungs. However, in the controls the size of acinar pathways was similar to Celsior preserved lungs whereas alveolar size was comparable to preservation with Euro-Collins. The between-animal coefficient of variation of alveoli was very low in controls and Celsior preserved but higher in the Euro-Collins group. Size distribution of alveoli and acinar paths in 15 size classes was largely homogeneous in all groups tested. In the Euro-Collins group the fractions of both class 1-alveoli and class 1-acinar paths significantly exceeded those of the other groups. Widely expanded alveoli (size classes 13–15) only occurred after preservation with Celsior whereas wider acinar paths (size class 15) were found in the Celsior group and in the controls. It is concluded that lung preservation with low-potassium Euro-Collins and Celsior solutions may act differently on distinct spaces in the distal gas-exchange regions of lungs. This may be due to selective effects on pulmonary surfactant activity and on elastic tissue elements in the alveolar ducts, respectively. Additionally, the method of point sampled intercepts is considered to be an efficient tool to evaluate the effects of different preservation solutions on lung parenchyma.     

Ischemia Induces Significant Changes in Purine Nucleoside Concentration in the Retina-Choroid in Rats

Adenosine, produced from the decomposition of adenosine triphosphate, is believed to provide protective effects during ischemia. On the other hand, adenosine metabolites may serve as precursors for oxygen free radical formation. The time course of formation of adenosine and its purine metabolites was studied during retinal ischemia in rats. Concentrations of adenosine and its purine nucleoside metabolites inosine, hypoxanthine, and xanthine in the retina-choroid of ketamine/xylazine-anesthetized rats were measured during retinal ischemia using high performance liquid chromatography. Quantitative measurements were made possible in the small tissue mass through the use of internal standards. Ischemia was induced by ligation of the central retinal artery. In each rat, one eye was ischemic while the other served as a non-ischemic control. Eyes were frozen in situ at 1, 5, 10, 20, 30, 60, and 120 min of ischemia. The retina-choroid was then removed from the frozen eyes and analysed. Significant increases in the concentrations of adenosine, inosine, and hypoxanthine in ischemic compared to control retina-choroid were detectable within 1 to 5 min of the onset of ischemia, and within 10 min for xanthine. Increase in adenosine concentration in ischemic relative to control retina-choroid plateaued at 30 min of ischemia, while inosine and hypoxanthine concentrations increased continuously. The increase in xanthine concentration was exponential throughout the measurement period. This study documented the time-related changes in purine nucleoside concentration during ischemia. Prolonged ischemia results in ongoing production of xanthine, which by serving as a precursor for oxygen free radical formation, could be a pathogenic factor in prolonged retinal ischemia.