Polyurethane Leads: Facts and Controversy

Une comparaison des électrodes de stimulation en polyuréthane et en silicone est présentée. Lorsue ľon compare tes qualités mécaniques et électriques, les qualités de friction et la stabilité hydrolytique, les deux matériaux paraissent capables ďêtre utilisés comme game des sondes ďélectrode. Néanmoins, en raison des craquelures de surface observé'es avecle polyuréthane il est nécessaire ďobtenir des surfaces aussi précises et parfaites que possible. De plus, les manoeuvres de torsion et de courbure doivent être évitées lors de ľimplantation. Enfin, la surveillance à long terme doit être assurée ďune façon routiniere.
A comparison of polyurethane and silicone cardiac pacing leads is presented. In comparing mechanical and electrical properties, friction coefficient and hydrolytic stability, both are highly qualified for use as electrode sheaths. The occurrence of surface cracking of polyurethane leads is examined. Several suggestions are proposed for dealing with the manufacture of new leads, the technique of implantation, and the follow-up required for successful surveillance.     

Risk Assessment for Coronary Interventions

Risk factors associated with a poor acute outcome of coronary interventions changed significantly as a result of the development of interventional techniques and adjunct pharmacological therapies. In the 1980s morphological parameters as classified by the modified AHA/ACC score were predictive of MACE. With advanced experience and technological improvements in the early 1990s only some lesion parameters retained their predictive power for balloon angioplasty. In the era of new devices some of the lesion parameters (bifurcational lesions, calcification) remained associated with a worse acute outcome, but procedure-related parameters (e.g., length of stented segment, remaining dissection) had more impact on the outcome. Some clinical parameters like age, presence of an acute coronary syndrome, and impaired left ventricular function are still predictive of a worse outcome. The impact of thrombocyte activation, which is an essential feature of the acute coronary syndrome, may be modified by application of GP IIb/IIIa inhibitors. Because of the different study designs, reported MACE rates among recently published studies differ significantly. A generalizable scoring system for risk assessment, which takes into account the different and conflicting study results, does not appear to be imminent.     

Clinical Impact of an Open‐Irrigated Radiofrequency Catheter with Direct Force Measurement on Atrial Fibrillation Ablation

Background: Electrode‐tissue contact is crucial for adequate lesion formation in radiofrequency catheter ablation (RFCA). Objective: We assessed the impact of direct catheter force measurement on acute procedural parameters during RFCA of atrial fibrillation (AF). Methods: Fifty consecutive patients (28 male) with paroxysmal AF who underwent their first procedure of circumferential pulmonary vein (PV) isolation (PVI) were assigned to either RFCA using (1) a standard 3.5‐mm open‐irrigated‐tip catheter or (2) a catheter with contact force measurement capabilities. Using the endpoint of PVI with entry and exit block, acute procedural parameters were assessed. Results: Procedural data showed a remarkable decline in ablation time (radiofrequency time needed for PVI) from 50.5 ± 15.9 to 39.0 ± 11.0 minutes (P = 0.007) with a reduction in overall procedure duration from 185 ± 46 to 154 ± 39 minutes (P = 0.022). In parallel, the total energy delivered could be significantly reduced from 70,926 ± 19,470 to 58,511 ± 14,655 Ws (P = 0.019). The number of acute PV reconnections declined from 36% to 12% (P = 0.095). Conclusions: The use of contact force sensing technology is able to significantly reduce ablation and procedure times in PVI. In addition, energy delivery is substantially reduced by avoiding radiofrequency ablation in positions with insufficient surface contact. Procedural efficacy and safety of this new feature have to be evaluated in larger cohorts. (PACE 2012; 35:1312–1318)     

ICD Therapy in Children and Young Adults: Low Incidence of Inappropriate Shock Delivery

Introduction: Implantable cardioverter defibrillator (ICD) therapy of life‐threatening arrhythmias in pediatric patients is feasible; however, recent studies report a high incidence of inappropriate shock deliveries. Methods: The data of all recipients of an ICD at the Charité, Department of Pediatric Cardiology, between January 2001 and November 2007 were retrospectively analyzed regarding underlying cardiac disorders, arrhythmias, medication, ablation procedures, leads and devices, programming, and ICD therapies. Results: A total of 33 patients underwent ICD implantation, with a median age of 16.5 years (range 8–36 years) and a mean weight of 61 ± 20.9 kg. Underlying cardiac disorders were electrical heart disease (27%), cardiomyopathy (30%), congenital heart disease (33%), and others (9%). Eighty‐five percent received antiarrhythmic drugs, and 12 ablation procedures were performed in nine patients (27%). The devices were programmed individually according to the underlying diseases and arrhythmias. During follow‐up, a total of 63 shock therapies were delivered in 11 patients, while a majority of 34 shocks occurred in one patient (no therapies in 22 of 33 patients). Only two such therapies were inappropriate, both delivered for atrial flutter. Conclusions: In children and young adults receiving ICD therapy, the combination of strategies to prevent ventricular arrhythmias using specific drug therapy, ablation procedures, and individual programming with improved devices and leads causes a low incidence of inappropriate shock delivery. (PACE 2010; 33:734–741)     

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.