Cryoablation of Medically Refractory Nodoventricular Tachycardia

Paroxysmal wide QRS tachycardia, based on a nodoventricular accessory connection, is an uncommon arrhythmia. In this report, the endocardial and epicardial mapping and cryoablation of a nodoventricular fiber, documented to participate in medically refractory tachycardia in an 11-year-old boy, are described. Epicardial cryothermia, applied at the earliest site of right ventricular activation, resulted in the abrupt termination of tachycardia. Endocardial cryothermia was subsequently applied in the perinodal region, the presumed site of origin of the nodoventricular fiber. No tachyarrhythmias were inducible postoperatively, and no antiarrhythmic treatment has been required during 18 months of follow-up. Based on precise anatomic localization of the nodoventricular connection, a definitive cure of associated tachyarrhythmias may be possible utilizing cryothermia, without the requirement for extensive intraoperative dissection.     

Diaphragm Pacing with a Quadripolar Phrenic Nerve Electrode: An International Study

We sought to determine the international experience with the quadripolar diaphragm pacer system and to test two hypotheses: the incidence of pacer complications would be (1) increased among pediatric as compared to adult patients; and (2) highest among active pediatric patients with idiopathic congenital central hypoventilation syndrome (CCHS). Data were collected via a questionnaire coupled with the Atrotech Registry data for a total of 64 patients (35 children and 29 adults) from 14 countries. Thoracic implantation of electrodes and bilateral pacer use each occurred in 94% of all subjects. Tetraplegic (vs pediatric CCHS) patients were more typically paced 24 hours/day (P = 0.001). Pacing duration averaged 2.0 ± 1.0 years among children and 2.2 ± 1.1 years among adults. Infections occurred among 2.9% of surgical procedures, all in pediatric CCHS patients (vs pediatric tetraplegic patients, P = 0.01). The incidence of mechanical trauma was 3.8%, without significant differences among patient groups. The incidence of presumed electrode and receiver failure were 3.1% and 5.9%, respectively, with internal component failure greater among pediatric CCHS than pediatric tetraplegic patients (P < 0.01). Intermittent or absent function of 0–4 electrode combinations occurred among 19% of all patients, with increased frequency among pediatric CCHS than pediatric tetraplegic patients (P < 0.03). Complication- free successful pacing occurred in 60% of pediatric and 52% of adult patients. In all, 94 % of the pediatric and 86% of the adult patients paced successfully after the necessary intervention. Although pacer complications were not increased among pediatric as compared to adult patients, the incidence of complications was highest among the active pediatric patients with CCHS. Longitudinal study of these patients will provide invaluable information for modification and improvement of the quadripolar system.     

Metabolic Balance Study of Plasmapheresis in a Case of Waldenstrom's Macroglobulinemia

A metabolic balance study was undertaken to evaluate the results of plasmapheresis in a case of Waldenström’s macroglobulinemia with an associatedcryoglobulinemia. Balances of nitrogen, P, Ca, Cl, and Na and K were carriedout. Additional observations were made on serum and urinary protein anduric acid. After a control period of 15 days, the subject was bled 500 cc. perday for 15 days. The plasma was separated by centrifugation and erythrocytesreinfused. A total of 500 Gm. of protein in 5,700 cc. of plasma were removedby this technic. A final control period was continued for 10 days. Plasmapheresis was observed to lower the abnormal plasma protein fraction from 7.5Gm. per cent to 4.5 Gm. per cent whereas the concentrations of the other plasma proteins remained unchanged. By the last day of the final control period,however, the abnormal protein concentration had risen to preplasmapheresislevels. The patient’s pronounced retinal venous dilatation and "sausage" segmentation were less marked at the end of the plasmapheresis period. The negative nitrogen balance during plasmapheresis was rapidly counteracted bydiminished urinary nitrogen excretion. At the same time, urinary protein excretion also fell. Na and Cl urinary excretion responded similarly to that ofnitrogen. P and K balances were slightly negative during plasmapheresis, probably reflecting tissue breakdown. Ca balance remained in equilibrium andurinary uric acid levels were unchanged. The study demonstrated that theelevated plasma paraprotein levels in a case of Waldenström’s macroglobulinemia may be lowered by plasmapheresis. Preplasmapheresis levels were rapidlyreestablished following discontinuance of the procedure.

Submitted on November 16, 1961 Accepted on December 21, 1961     

Hepatic Changes Produced by 30-Day Administration of a Novel Aminocyclitol Antibiotic, Trospectomycin Sulfate, to Laboratory Animals

Hepatic Changes Produced by 30-Day Administration of a NovelAminocyclitol Antibiotic, Trospectomycin Sulfate, to LaboratoryAnimals. ULRICH, R. G., PETRELLA, D. K., LARSEN, E. R., COX,J. W., CRAMER, C. T., PIPER, R. C, AND GRAY, J. E. (1990). Fundam.Appl. Toxi-col. 14, 60–70. The studies described herewere done to characterize the hepatic response to a new aminocyclitolantibiotic, trospectomycin sulfate, administered intravenously(beagle dog) or subcutaneously (Sprague-Dawley rat) at a varietyof dose levels, to investigate reversibility of observed changes,and to document any untoward effects of subchronic trospectomycinsulfate administration. Both species showed significant elevationsin serum levels of alanine and aspartate transaminases in higherdose groups. In the dog only, a transient neuromuscular blockadewas also observed within higher dose groups. No other functional,morphological, or serum chemical changes were observed. Examinationof liver by electron microscopy revealed the presence of cytoplasmiclamellar inclusion bodies, concentrated in the bile canalicularregion of the hepatocytes. Occurrence of the lamellar bodiesand coincident transaminase increases were found to be reversibleupon discontinuance of treatment (studied in the dog). Electronmicroscopy of acid phosphatase cytochemistry in the rat indicatedthat most, but not all, of the lamellar bodies contained thisenzyme. This observation suggests that they may be derived fromthe lysosome, or once formed become lysosomal.     

The Inventory to Diagnose Depression (IDD) in Primary Care Patients

Major depressive disorder (MDD) is highly prevalent in ambulatoryprimary care patients. Severe functional impairment and riskof suicide are features of the condition. Although treatmentcan reduce morbidity, detection of MDD by primary care physiciansis suboptimal. The aim of this study is to assess the inventoryto diagnose depression (IDD) as compared with clinical psychiatricassessment for case finding in primary care patients. Adultmembers of an Israeli kibbutz (communal settlement), where allpsychiatric diagnoses made by the family physician are confirmedby psychiatric consultation, were asked to complete the IDD;a 22 question, self-administered questionnaire. Patients whosescores indicated MOD, if not previously diagnosed, were alsoreferred to psychiatrists. Patients' medical charts were reviewedfor the diagnosis of MDD and response to therapy prior to theadministration of the IDD. Of the sample of 312 patients, 207(66.3%) completed the IDD. Refusers were younger (p = 0.04),more likely to be native born Israelis (p = 0.02), and had ahigher prevalence of known MDD (p = 0.05) than participants.MDD by IDD scores was present in seven patients, in three ofwhom the diagnosis had previously been established; the otherfour were newly diagnosed. In the three previously diagnosedpatients, one (metastatic carcinoma) refused treatment and twowere receiving psychotherapy; all were clinically depressed.Four additional previously diagnosed patients whose IDD scoreswere insufficient for MDD had had a successful response to currenttherapy. A full test of the validity of the IDD as a diagnosticinstrument as com pared with clinical psychiatric assessmentas the criterion standard, requires concurrent assessment withboth methods of all patients studied. Although patients withnegative IDD scores did not receive psychiatric assessment,the diagnosis of MDD was confirmed by psychiatrists in all patientswith positive scores.     

Appraisal of the Intramuscular Irritation Test in the Rabbit

Appraisal of the Intramuscular Irritation Test in the Rabbit.Gray, J.E. (1981). Fundam. Appl. Toxicol. 1:290–292. Musculoirritancytesting in the rabbit has been recognized as sufficiently sensitiveto be highly predictive of human tolerance for intramuscularlyadministered drugs. A three-part study consisting of gross characterizationof the lesion, microscopic observation and determination ofserum activity of the enzyme creatine phosphokinase (CPK) hasevolved as a standard test for evaluating single injection injuryin the muscle. Injection and tissue processing procedures aredescribed as well as a revised grading system for gross examinationbased on degrees of necrosis and hemorrhage, respectively. Basedon 213 determinations, the control mean serum CPK activity was262 + 1131.U./liter. The importance of pretest acclimation ofrabbits in establishing this value was emphasized. Designationsof slight, moderate, or marked irritation are based on accumulativescoring of all rabbits at postinjection intervals of 1,3, and7 days. At 24 hr postinjection, serum CPK activities up to andincluding a range of 2000–30001.U./liter have been shownto be compatible with slight irritation and are considered predictiveof human tolerance.