A Unique Preexcitation Pattern Related to an Atypical Anteroseptal Accessory Pathway

Accessory atrioventricular pathways have traditionally been classified by anatomical Jocation to four areas, namely anteroseptal, posteroseptal, and right and left free walls. Each of these have been associated with a relatively distinct preexcitafion pattern electrocardiographically. We describe a patient with a unique EGG pattern suggesting preexcitation to the right ventricular outflow region, Preoperative and intraoperative electrophysioJogicaJ testing confirmed the presence of an accessory pathway with an atrial insertion site near the His bundle, decremental anterograde conduction, and a ventricular insertion site in the upper part of the interventricular septum. Operative ablation near the atrial insertion site eliminated preexcitation.     

Atrial Flutter Secondary to Hypokalemia

Electrophysiologic studies support significant hypokalemia as a cause of atrial flutter in a patient without manifest heart disease. Atrial flutter, reproducibly initiated and terminated by rapid atrial pacing during hypokalemia, was not inducible after potassium correction. In an individual with existing atrial conduction disease, hypokalemia may generate both non-uniform atrial refractoriness and atrial premature beats, and it may facilitate the development of atrial flutter as a re-entrant arrhythmia.     

Insulation Failure with Bipolar Polyurethane Pacing Leads

Between October, 1981, and April, 1983, 200 pacemakers were inserted at Rhode Island Hospital. Forty-five bipolar polyurethane leads (Medtronic 6972) were positioned in the right ventricle. Three (6.6%) of these leads presented 15 to 18 months post-implant with insulation failure. The manifestation was inappropriate inhibition of the pacemaker. No obvious cracking was visible on X-ray or during surgery. All the leads had low impedance, indicative of insulation failure.     

Characteristics of Mohs Practices in the United States: A Recall Survey of ACMS Surgeons

OBJECTIVE The purpose of this study is to better characterize the typical Mohs practice in the United States and to generate data that may be useful in future practice models.
METHODS A survey was mailed in 2004 to all 599 members of the American College of Mohs Surgery with United States addresses listed in the 2003 directory.
RESULTS Most respondents were part of a single speciality group, in a suburban or urban setting, performed between 501–1,000 cases per year, and had been in practice from 0–5 years. The vast majority of Mohs excisions are for basal cell cancers and squamous cell cancers, followed by melanoma. Primary closure is the most common method of repair, followed by the use of flaps. Only 6% of cases were referred to other specialties for closure. Many surgeons augment their practice with non-Mohs cosmetic procedures.
CONCLUSION The characteristics of current Mohs surgery practices in the United States provides useful data for training programs, potential trainees, workforce issues, statistical modeling systems, and Mohs surgeons in the evaluation of their own practices.     

Nephrotoxic and Ototoxic Effects of Hydroxygentamicin in Cats

Nephrotoxic and Ototoxic Effects of Hydroxygentamicin in Cats.Slighter, R. G, FABIAN, R. J., DONIKIAN, M. R., RENCH, R. D.,NEIDL, M. J., AND BOSHART, C. R. (1984). Fundam. Appl. Toxicoi.4, 568–576. Hydroxygentamicin, an aminoglycoside antibiotic,was administered subcutaneously to cats in doses up to 160 mgbase/kg daily for 10 to 13 weeks. Gentamtcin and a vehide solutionwere tested as positive and negative control, respectively;in one test netilmicin was also included for comparative purposes.Several parameters, including serum urea nitrogen, serum creatinine,organ/body weight ratios, serum and tissue concentrations ofthe antibiotics, and renal pathology, were determined to ascertainthe nephrotoxic potential of the three ami-noglycosides. Inaddition, observations for the onset of ataxia and impairmentof righting reflex were made during the course of the studiesto compare the vestibular ototoxic effects of the three antibiotics.Although serum urea nitrogen and serum creatinine values increasedmarkedly in those cats which eventually died or were sacrificedmoribund, these parameters in survivors were slightly but notsignificantly higher than controls. -Serum concentrations ofthe drugs were proportional to the doses administered, but renalconcentrations were approximately two and five times as highfor netilmicin and gentamicin, respectively, as they were forequivalent doses of hydroxygentamicin. The morphological changesobserved in the kidney of cats given 60 mg base/kg of hydroxygentamicinwere slightly less than those seen in cats administered 10 mgbase/ kg of gentamicin; similarly, kidney changes in cats givennetilmicin were observed approximately twice as frequently asthey were in those receiving equivalent doses of hydroxygentamicin.The nephrotoxic effects of aminoglycoside antibiotics were directlyrelated to renal drug concentration and not to serum concentration,which was a function of dose. The reason for the lower incidenceof vestibular ototoxic effects with hydroxygentamicin than withgentamicin was not as readily apparent. Vestibular damage resultingfrom netilmicin administration was restricted to ataxia; thelack of righting reflex impairment in all five cats was notcharacteristic of the pattern of vestibular ototoxicity associatedwitn aminoglycoside therapy.     

Two-Generation Reproduction Study of Ethylenediamine in Fischer 344 Rats

Two-Generation Reproduction Study of Ethylenediamine in Fischer344 Rats. YANG, R. S. H., GARMAN, R. H., WEAVER, E. V., ANDWOODSIDE, M. D. (1984). Fundam. Appl. Toxicol. 4, 539–546.Ethylenediamine dihydrochloride (EDA {dot} 2HC1) was incorporatedin the diet of Fischer 344 rats at dosage goals of 0.50, 0.15,0.05, or 0 g/kg/day in a two-generation reproduction study.The parent generation (F₀) and the F₁ generation were each bredonce. Parameters examined included indices of fertility, gestationof dams, gestation survival, 0- to 4-, 4- to 14- and 4- to 21-daysurvival of pups, number of pups born alive, and number of pupsweaned per litter. Furthermore, observations were made on mortality,diet consumption, and body weight of the adult rats in F₀ andF₁ generation. Randomly selected F₁ weanlings and adults andF₂ weanlings were sacrificed and organ weights were obtained;in addition, gross and histologic examinations were conductedon these rats. No reproductive toxicity was observed in thisstudy. Some effects were observed in both sexes for the F₀ andF₁ parent rats. These effects were mainly associated with thehigh dosage level and included reduction of body weight gainand changes in liver (decrease) and kidney (increase) weightsin the adult rats. The only microscopic lesion observed washepatocellular pleomorphism in the high level F₁ adult malesand females; a greater prevalence and severity of this lesionwas seen in the female rats.