Antiarrhythmic Effects of VVI Pacing at Physiologic Rates: A Crossover Controlled Evaluation

Ventricular pacing can prevent bradycardia-dependent ventricular ectopic activity (VEA) and is helpful in some cases of drug-refractory venfricuiar tachycardia (VT). This study is a prospective evaluation of VVI pacing for the control of VEA not related to underlying bradycardia, drug side-effects, or prolonged QT interval syndromes. Twenty-nine patients undergoing serial electrophysioiogic-pharmacoiogic testing for VT control were studied. Eighteen of these patients (12 men; meon age = 60.1) both completed ihe protocol and had sufficient VEA for analysis. Coronary disease was present in 13 patients, cardiomyopathy in two patients, and one patient each had myocarditis, mitral valve prolapse, and no structural heart disease. Ambulatory (Holter) monitor recordings during VVI pacing were compared with control recordings made in the absence of pacing, VVI pacing rates were 10–15 bpm above the mean daily heart rate (mean = 92 bpm; range = 63–110). Hours from paced recordings were paired with hours from control (prior to analysis) according to time of day to reduce the effects of spontaneous variability in VEA frequency. Overall, VVI pacing reduced ventricular premature complexes (VPGs) 26% from 331 to 245/hour (p < 0.001). During pacing, couplets (pairs, successive VPGs) were reduced from 6.95 to 1.03/hour (p < 0.000001) and VT (≥3 successive VPCs) from 0.89 to 0.045 episodes/hour (p < 0.003). Of 13 patients with couplets, 11 had ≥50% reduction and five had ≥90% reduction. Baseline VT was eliminated in four out of nine patients during pacing. Pacing did not increase VEA significantly in any patient. In this group of patients, reduction of VEA by VVI pacing was significant and was comparable to pharmacologic interventions. Higher forms of VEA fcouplets and VT) appeared to respond better than single VPCs. Further studies may define patients with VEA who can benefit from pacing     

Evaluation of emergence delirium in Asian children using the Pediatric Anesthesia Emergence Delirium Scale

Background: Emergence delirium (ED) is a common problem in children recovering from general anesthesia. ED causes disruption in the postanesthetic care unit, making nursing and monitoring more difficult, and is potentially dangerous to the child. The greatest hindrance to understanding ED was the lack of a standardized tool to assess it. The Pediatric Anesthesia Emergence Delirium (PAED) Scale was recently described to measure the degree of ED in children. In this prospective observational study, we sought to evaluate the incidence of ED by grading emergence behavior using the PAED Score in healthy Asian children undergoing outpatient surgery. Methods: Three hundred sixteen children aged 2–12 years undergoing general anesthesia for elective outpatient surgery were included. No premedication was administered. Induction behavior was graded using the induction compliance checklist, and the presence of any excitation on induction documented. Emergence behavior was recorded using the PAED Scale, and the children were separately assessed for clinical agitation. Results: One hundred and thirty‐six children (43%) had PAED Scores >0 and 33 (10.4%) had PAED Scores of ≥10. Only 28 children (8.9%) had clinical agitation consistent with ED, the rest were agitated for other reasons. A score of ≥10 on the PAED Scale was the best discriminator between presence and absence of clinical agitation. The area under the receiver operating characteristic curve for PAED Score of ≥10 was 0.98, with a true‐positive rate (sensitivity) of 0.85 and a false‐positive rate (1‐specificity) of 0.041. Four factors were found to be predictive of ED. These include young age, poor compliance at induction, lack of intraoperative fentanyl use and rapid time to awakening. Conclusions: The incidence of ED is approximately 10% in our population of healthy, unpremedicated Asian children undergoing day surgery. Young age, poor compliance at induction, lack of intraoperative fentanyl use and rapid time to awakening were predictive risk factors for ED in our population. A PAED Score of ≥10 was correlated with clinically significant ED and appeared to be the ideal cutoff score for ED.     

Recombinant human epidermal growth factor treatment of radiation-induced severe oral mucositis in patients with head and neck malignancies

Mucositis of the oral cavity and pharynx is a major dose-limiting factor in the application of radiotherapy (RT) to patients with head and neck cancer. Therefore, we evaluated the wound healing effect of human recombinant epidermal growth factor (rhEGF) in head and neck cancer and lymphoma patients with irradiation (with or without combined chemotherapy-induced oral mucositis). Patients at Asan Medical Center who had undergone definitive RT of the head and neck region with or without combined chemotherapy and who had developed severe oral mucositis (higher than the Radiation Therapy Oncology Group grade 3) were treated with topical rhEGF twice daily for 7 days. The evaluation of response with regard to oral mucositis was performed 1 week later. Of the 11 treated patients, three had nasopharyngeal carcinoma, three had carcinoma of the oropharynx, two had carcinoma of the oral cavity, one had carcinoma of the hypopharynx and two had lymphoma of the head and neck. Six patients received RT only, and five patients received concurrent chemoradiotherapy. All patients showed improvements in their oral mucositis after topical treatment with rhEGF in that the Radiation Therapy Oncology Group grade was significantly decreased ( P  = 0.0000). This finding suggests that rhEGF is effective and safe for the treatment of radiation-induced mucositis. Further studies are needed to determine the optimal dosage and fractionation schedule.     

In vivo comparison of force development with various materials of implant-supported prostheses

Summary  The purpose of this study was to measure axial loading, generating bending moments on fibre reinforced composite (FRC) implant prostheses using strain-gauged customized abutment in vivo . Bending moments of conventional implant prosthetic material were also measured and the data were compared with those for FRC. Three unit fixed dental prostheses were made for two dental implant fixtures, which had been functioning properly for more than one year using Tescera^TM ATL^TM, porcelain fused to metal and gold as occlusal material. Three patients participated in this study; two patients had two implants on one side of the mandible and one had two implants on both sides of the mandible. Five sets of fixed dental prostheses were fabricated for each material and these were cemented with Temp-bond^® on strain-gauged customized abutments, which were screwed into the underlying implant fixtures. Axial loadings and bending moments were measured when a patient bit the experimental fixed dental prosthesis. anova and the Tukey HSD test (α = 0·05) were used for statistical analysis. There were no significant differences in normalized bending moments among the three different implant prosthetic materials. Within the limitations of this study, Tescera^TM ATL^TM generated bending moments similar to conventional implant prosthetic materials such as gold and porcelain.     

Effects of Electrocautery on Transvenous Lead Insulation Materials

Introduction: Insulation defects are a leading cause of transvenous lead failure. The purpose of this study was to determine the effects of electrocautery on transvenous lead insulation materials.
Methods: A preparation was done to simulate dissection of a transvenous lead from tissues. Radiofrequency energy was delivered using a standard cautery blade at outputs of 10, 20, and 30 W, for 3 and 6 seconds, using parallel and perpendicular blade orientations on leads with outermost insulations of silicone rubber, polyurethane, and silicone–polyurethane copolymer. Damage to each lead segment was classified after visual and microscopic analysis.
Results: Significant insulation damage occurred to almost all polyurethane leads. Full insulation breaches were observed with 30 W regardless of application duration with a parallel direction and with all power outputs with a perpendicular direction. Thermal insulation damage to copolymer insulation was similar to that of the polyurethane leads. In contrast, there was no thermal damage to silicone leads, regardless of the power output and duration of power delivery. However, mechanical insulation damage was observed to all silicone leads when at least 20 W was applied in a direction perpendicular to the lead.
Conclusions: Polyurethane (PU55D) and copolymer materials have low thermal stability and are highly susceptible to thermal damage during cautery. Implanting physicians should be aware of the lead insulation materials being used during implant procedures and their properties. The use of direct contact cautery on transvenous leads should be minimized to avoid damage to the lead, especially on leads with polyurethane or copolymer outer insulations.     

Pigmented nail with atypical melanocytic hyperplasia

We report two cases showing black discoloration of the thumb nail which were histologically found to be acral lentiginous melanoma (ALM) in situ. A pigmented subungual lesion is more frequently malignant than benign and it is generally believed that diagnosis of subungual melanoma during the radial-growth phase is very difficult. Our cases are particularly interesting because atypical melanocytic hyperplasia was confined to the epidermis despite the lesion being present for a long time.     

Nonsurgical Electrical Ablation of Tachycardias: Importance of Prior in Vitro Testing of Catheter Leads

Nonsurgical electrical ablation of tachycardia pathways or foci has been attempted or carried out using a variety of temporary pacing catheter leads. To determine the ability of such leads to withstand the high energies used in such procedures, 34 leads were suspended in saline, and subjected to repeated electrical shocks. Small (4 French) temporary pacing leads made by a variety of manufacturers tolerated multiple shocks up to 100 joules; above this level, failures became increasingly common, although usually the failure mode was benign with respect to patient care implications. Testing of 6, 7, and 8 French leads revealed considerable inter-and intra-manufacturer differences in the ability to withstand higher energy shocks, reflecting differences in materials and fabrication techniques. It is concluded that careful in vitro lead testing is required prior to using identical models in humans for arrhythmia ablation procedures.     

The Clinico-pathologic Features of Hepatitis B Virus-associated Glomerulonephritis

The frequency of hepatitis B Surface antigen (HBsAg) was studiedin the sera of 311 patients with various forms of primary glomerulonephritisand 43 patients with lupus nephritis. HBs antigenaemia was detectedin 69 of the 311 patients (22 per cent) with primary glomerulonephritisand this prevalence of HBaAg carrier was significantly higherthan that in the general population (p<0. 001). These patientshad no clinical or biochemical findings to suggest acute orchronical liver disease. A higher HBs antigenaemia carrier ratewas not observed in patients with lupus nephritis. Three glomerulopathologicalentities, membranous nephropathy. IgA nephropathy, and mesangialproliferative glomerulonephrities, were found to be associatedwith a higher prevalence of HBs antigenaemia compared with thegeneral population (p<0. 001). Glomerular deposits of HBsAgand/or hepatitics core antigen (HBcAg) were detected in 41,61, and 60 per cent of renal biopsy specimens from patientswith membranous nephropathy, Iga nephropathy, and mesangialproliferative glomerulonephritis associated with persistentHBs antigenaemia respectively. During the mean study periodof 40 months (range 12–180), 14 per cent of these patientswith hepatitis-associated glomerulonephrities developed progressiverenal failure, althrough none required maintenanece dialysis.Our study suggests that hepatitis B virus antigenaemia may playa significant role in the developement of specific forms ofglomerulonephritis and that these hepatities B virus-associatedglomerulonephritides can run an indolent but relentless progressiveclinical course.     

The Effect and Safety of the Antithrombotic Therapies in Patients with Atrial Fibrillation and CHADS2 Score 1

Anticoagulation in CHADS₂ Score 1 . Background: The revised ACC/AHA/ESC 2006 guideline recommends either aspirin or warfarin for the prevention of ischemic stroke in patients with atrial fibrillation (AF) in CHADS₂ score 1. We hypothesized that warfarin is superior to aspirin therapy for the prevention of stroke without increasing bleeding complication in AF patients with CHADS₂ score 1. Methods and Results: Among 1,502 patients (mean 62.4 ± 13.8 years old, male 65.4%) who were treated for nonvalvular AF without previous stroke, the number of patients with CHADS₂ score 1 was 422 (62.9 ± 10.7 years old, male 290 [68.7%]) and their antithrombotic therapies were as follows: warfarin (n = 143), aspirin (n = 124), other antiplatelet (n = 45), and no antithrombosis (none: n = 110). We reviewed the incidences of ischemic stroke, mortality, and bleeding complications during the follow‐up period. Results were: (1) during 22.3 ± 17.8 months of follow‐up, the incidence of ischemic stroke was significantly lower in warfarin (6 patients, 4.2%, mean international normalized ratio [INR] 2.0 ± 0.5 IU) than in aspirin (16 patients, 12.9%, P = 0.008) than none (23 patients, 20.9%, P < 0.001) without differences in all‐cause mortality. (2) The incidence of major bleeding (decrease in hemoglobin ≥2 g/dL, requiring hospitalization or red blood cell transfusion ≥2 pints) was not different between warfarin (2.1%) and aspirin (0.8%, P = NS), but minor bleeding was more common in warfarin (10.5%) than in aspirin (2.4%, P = 0.007). Conclusion: In AF patients with CHADS₂ score 1, warfarin was better to prevent ischemic stroke than aspirin without increasing the incidence of major bleeding complications. However, the incidence of minor bleeding was higher in the warfarin group than the aspirin group. (J Cardiovasc Electrophysiol, Vol. 21, pp. 501‐507, May 2010)