Steroid-Eluting Epicardial Pacing Electrodes: Six Year Experience of Pacing Thresholds in a Growing Pediatric Population

Indications for pacemaker implantation in the pediatric population often include sinus or atrioventricular node dysfunction following surgery for congenital heart defects. However, patient size, cardiac defects, and vascular and valvular concerns may limit transvenous lead utilization. Since the epicardial surface of these patients often exhibits variable degrees of fibrosis from scar tissue formation or pericardial adhesions, chronic low output (2.5/1.6 V, 0.3 ms) epicardial pacing from implant is not currently recommended in children due to frequent threshold changes and electrode exit block. As a result, pacing in children is often viewed as a less efficient system than in adults. The addition of steroid combined with newer low threshold electrode designs however stabilizes the electrode-tissue interface and eliminates postimplant changes seen with standard smooth surface electrodes potentially permitting efficient chronic pacemaker application to all patient ages. The stability of chronic low output epicardial pacing with steroid-eluting electrodes was prospectively studied in 22 patients (ages 2 days-18.5 years, median 3.5 years) for up to 6 years. Chronic pulse width thresholds were compared according to implant site and association of prior cardiac surgery. A total of 26 pacing leads were implanted. The acute implant mean pulse width threshold (2.5 V) for all the electrodes studied was 0.10 ms ± 0.05 ms. Stable low thresholds were maintained for up to 6 years without significant variation from implant. Mean ventricular pulse width thresholds (0.12 ms ± 0.05 ms) were significantly higher (P < 0.001) than atrial thresholds (0.06 ms ± 0.03 ms) at implant and throughout the study period. The thresholds in the patients following cardiac surgery were comparable to those without previous cardiac surgery (P = NS). Stable low thresholds may be chronically maintatined for up to 6 years for epicardial steroid-eluting electrodes irrespective of pacing site or associated cardiac surgery.     

PSYCHOSOCIAL ADJUSTMENT AFTER TESTICULAR CANCER TREATMENT

Purpose

The high cure rate in testicular cancer has provoked investigations relating to the quality of life in long-term survivors. We determine the psychosocial consequences of the disease especially in regard to sexual and professional performance.

Materials and Methods

Among the testicular cancer patients treated with various treatment modalities 140 rendered free of disease for at least a year were included in this study. General Health Questionnaire 28 and a general survey were used to determine quality of life issues.

Results

Regarding the sexual life of these patients, problems related to libido, erection and ejaculation increased significantly during treatment and subsequently recovered but did not return to baseline after treatment. During treatment the frequency of sexual intercourse and/or masturbation decreased significantly in all patients. Of the single patients 35% thought that medical history would be a concern for the potential spouse. Regarding professional lives, 22.4% thought that they had better performance after treatment compared to before therapy, whereas only 6.1% reported it to be worse. When professional performance was analyzed according to the treatment modalities those who had received radiotherapy did worse. General Health Questionnaire scores indicated that patients with this disease had a positive view of life compared to that of the normal population.

Conclusions

Although we observed a substantial recovery in sexual life after treatment, it was evident that therapy did have a negative effect on sexual functions. There was no effect on occupational performance and perspective of life, which may be related to the fact of having overcome a life threatening disease.     

Prediction of Head‐Up Tilt Test Result: Is it Possible?

Background: The determination of early, accurate, predictive criteria for a positive result would permit a reduction in the duration of the head‐up tilt testing (HUTT). Previous studies propounded that existence of early sympathetic overreactivity (rapid and sustained increase in heart rate) during HUTT predicts positive result. However, the exact value of this variable is unknown. We analyzed the early heart rate (HR) responses to HUTT and evaluated their ability to predict HUTT result. Methods: Consecutive patients referred to the syncope unit of our center for recurrent unexplained syncope were studied. Results: We studied 189 consecutive patients and 67 (35%) patients had a negative HUTT; 122 (65%) patients had a positive HUTT. The early HR increase was defined as the maximum HR during the first 10 minutes of tilting minus the resting HR before tilting. The receiver–operator curves (ROCs) show the overall performance of the HR changes for predicting the HUTT result. For all variables, area under the ROC curve (AUC) was nearly equivalent to 0.50 and early HR increase was not a predictor of the negative result of HUTT (AUC = 0.546). Also there was no any significant correlation between the magnitude of early HR increase and patient age (r =?0.03, P = 0.76). Conclusions: The results suggest that the early increase in HR during the first 10 minutes of the HUTT may not be a useful parameter for predicting the test result. Many factors, such as late exaggeration in sympathetic activity during HUTT and age‐dependent reduction in baroreflex sensitivity, may attenuate the predictive value of early HR increase. (PACE 2010; 33:153–158)     

Heart Obeys the Brain: Seizure Ceases Cardiac Rhythm

Ictal asystole is a rare phenomenon which may contribute to sudden death during epilepsy. Here we describe a case of a 20‐year‐old woman with ictal asystole and normal findings during electrophysiologic study. This case illustrates that ictal asystole may occur in patients with electrically normal hearts. We provide pathophysiologic considerations and discuss therapeutic options. (PACE 2010; e72–e75)     

Numerical study of effect of elastomeric stress absorbers on stress reduction in bone-dental implant interface

Objective

This paper focused on optimal stress distribution in the mandibular bone surrounding a dental implant and is devoted to the development of a modified Osteoplant^® implant type in order to minimize stress concentration in the bone-implant interface.

Material and Methods

This study investigated 0.4 mm thick layers of two elastomeric stress barriers incorporated into the dental implant using 3-D finite element analysis.

Results

Overall, this proposed implant provoked lower load transfer in bone-implant interface due to the effect of the elastomers as stress absorbers. The stress level in the bone was reduced between 28% and 42% for three load cases: 75 N, 60 N and 27 N in corono-apical, linguo-buccal and disto-mesial direction, respectively.

Conclusion

The proposed model provided an acceptable solution for load transfer reduction to the mandible. This investigation also permitted to choose how to incorporate two elastomers into the Osteoplant^® implant system.     

An RFLP map for 2q33-q37 from multicase mycobacterial and leishmanial disease families: no evidence for an Lsh/Ity/Bcg gene homologue influencing susceptibility to leprosy

The mycobacterial disease leprosy and tuberculosis (TB) and the leishmaniases are characterized by a wide spectrum of disease phenotypes, and by the fact that the majority of individuals exposed to the causative organisms Mycobacterium leprae, M. tuberculosis and Leishmania sp. become infected but do not present with clinical disease. In order to determine whether a human homologue to the murine macrophage resistance gene Lsh/Ity/Bcg influences susceptibility to human disease, multicase families for all three disease have been collected, and linkage analysis performed using a panel of markers in the region of human chromosome 2q33-q37 known to be conserved with the Lsh/Ity/Bcg -containing region of murine chromosome 1. Because of the paucity of available polymorphic markers/linkage information for 2q33-q37, data from 35 multicase leprosy, TB and visceral leishmaniasis families (310 individuals) were first pooled to produce a detailed RFLP map of the region. Peak LOD scores well in excess of 3 were observed for linkage between adjacent pairs of a more proximal (2q33-q35) set of markers CRYGP1, MAP2, FN1, TNP1, VIL1 and DES, and between adjacent pairs of a more distal (2q35-q37) set COL6A3, D2S55 and D2S3. These peak LOD scores and the corresponding values for θ were used in the MAP92 program to generate a multiple two-point map with gene order/map intervals (cM) of: CRYGP1-4.65-MAP2-3.45-FN1-5.95-TNP1-3.41-VIL1-3.01-DES-20.14-COL6A-10.91-D2S55-3.67-D2S3. Although local support for the placement of loci in this order was weak (LOD 2, except for DES-COL6A3 where LOD = 6.02), the map is consistent with the gene order for those loci ( Cryg, Fn-1, Tp-1, Vil, Des, Col6a3 ) previously mapped in the mouse. Data from 17 multicase leprosy families (149 individuals) were further analysed for linkage between a putative disease susceptibility locus (DSL) con