Characteristics, Circuit, Mechanism, and Ablation of Reentry in the Rabbit Atrioventricular Node

INTRODUCTION: The circuitry underlying AV nodal reentry remains debated. We developed a model of AV nodal reentry and assessed the role of nodal inputs, compact node, and its posterior nodal extension (PNE) in this phenomenon. METHODS AND RESULTS: A fine scanning of short coupling interval range with an atrial premature beat consistently initiated slow-fast AV nodal reentrant beats that occurred 37+/-31 msec (mean+/-SD) after His-bundle activation in 11 of 16 consecutive rabbit heart preparations. The repeated testing (>40 times) of a chosen coupling interval within reentry window (6+/-9 msec, n = 11) yielded reentrant intervals that varied by 2+/-1 msec (mean SD for 40 beats+/-SD, n = 11). The breakthrough point of reentrant activation, as assessed from four perinodal sites, varied in different preparations from diffuse (4) to anterior (1), medial (3), or posterior (3); mean reentrant interval did not differ between perinodal sites. Antegrade perinodal activation pattern did not differ at reentrant versus nonreentrant coupling intervals and thus was not a primary determinant of reentry. A PNE ablation (n = 4) interrupted the slow pathway conduction and prevented reentry without affecting antegrade perinodal activation or fast pathway conduction. CONCLUSION: A reproducible model of AV nodal reentrant beats was developed and used to study underlying circuitry. The AV nodal reentry involves unaltered antegrade perinodal activation, slow PNE conduction and retrograde broad invasion of perinodal tissues starting at a preparation-dependent breakthrough point. A PNE ablation abolishes the reentry.     

THE DIAGNOSIS OF PONCET'S DISEASE

Two cases of polyarthritis in young people with extra-articulartuberculosis are described. The clinical features were consistentwith the concept of Poncet's disease. After synovial biopsyone patient proved to have tuberculous peripheral arthritis.This observation raised doubts about the diagnosis in the otherpatient. Multiple joints may be simultaneously infected withMycobacterium tuberculosis and Poncet's disease, if it exists,should not be entertained in the absence of synovial biopsy. KEY WORDS: Polyarthritis, Tuberculosis, Synovial biopsy     

Upper Gastrointestinal Endoscopy in Saudi Arabia: Analysis of 6386 Procedures

SUMMARY Fibreoptic endoscopy is now established in the investigationof upper gastrointestinal disease. We report our findings ina large series of endoscopic procedures (6386) mostly in MiddleEastern Arabs, and compare the results obtained in Western patients.We find fibreoptic endoscopy to be feasible, safe, acceptableand effective     

Serum Gastrin in Patients with Various Types of Chronic Gastritis

Fasting serum gastrin was determined in 35 Chinese patients with various types of chronic gastritis and in 23 Chinese control subjects. The mean (± S.D.) fasting serum gastrin levels for 13 patients with chronic atrophic gastritis, 16 patients with chronic gastritis and six patients with acute-on-chronic gastritis were 32.1 (± 38.9) pg./ml., 36.1 (± 23.2) pg./ml. and 33.7 (± 19.4) pg./ml., respectively. The mean (± S.D.) fasting serum gastrin levels for the whole gastritis group (35 patients) and the control group were 34.2 (± 28.8) pg./ml. and 24.6 (± 13.7) pg./ml., respectively. Statistical analysis showed that the mean basal serum gastrin levels of the three gastritis groups did not differ significantly from control subjects and with each other.