Do Electrode and Lead Design Differences for Permanent Cardiac Pacing Translate into Clinically Demonstrable Differences? (Comparison of Sintered Platinum and Activated Vitreous and Porous Carbon Electrodes)

A randomized prospective study was undertaken to compare the electrical performances of three permanent, endocardial, tined pacing leads with different electrode designs--sintered platinum, vitreous carbon, and porous carbon. Ninety-nine patients received one of the leads (S80 31; 423S 32; S100 36). Acute R wave amplitude and ST elevation of the native endocardial electrogram, voltage threshold, impedance, and current flow at four pulse durations (0.25-1.0 msec) were measured. Voltage thresholds were measured noninvasively at each of four pulse durations at 2 days and 1, 3, and 6 months after implantation. No significant differences were found in sensing properties, or current flow at threshold at 0.5 msec pulse duration. The 423S lead had a significantly higher impedance at threshold and both a higher impedance and lower current flow at 5 V. No significant differences in threshold voltages were found between the three leads at any pulse duration, at any of the assessed times after implantation. Six-month thresholds for the S80, 423S, and S100 leads were 1.18 +/- 0.35, 1.17 +/- 0.29, and 1.06 +/- 0.38 V respectively at 0.5 msec pulse duration. Differences between 'high performance' pacing leads need to be of a greater order of magnitude before they can be exploited to give any real clinical advantage to patients.     

The prevalence of coeliac disease in adult diabetes mellitus

Coeliac disease occurs more commonly in children with insulin-dependentdiabetes mellitus (IDDM) than in the general population, butthe prevalence of coeliac disease in adults with diabetes isunknown. We therefore screened an adult hospital-based diabeticpopulation using IgA antigliadin antibody (IgA-AGA) to identifythose patients requiring intestinal biopsy. In 1 year, 1789patients (43% IDDM, 57% NIDDM) were screened, and 73 had raisedIgA-AGA. Of these patients, 49 agreed to duodenal biopsy and13 (10 IDDM) had coeliac disease. Selective IgA deficiency wasfound in eight patients, one of whom had coeliac disease. Ofthese 14 patients with newly diagnosed coeliac disease, fourhad microcytic anaemia, nine a low serum ferritin, and foura low albumin-corrected calcium. Eight patients had symptomswhich improved on gluten withdrawal. Dietary compliance wasmaintained in 6/8 symptomatic patients, but only in 1/6 withoutsymptoms. Included in the 1789 patients were four (all IDDM)with known coeliac disease. The overall prevalence of coeliacdisease in adult patients with IDDM was 1:50 compared with 1:340in NIDDM. Coeliac disease is common in adults with IDDM andmay cause malabsorption and ill health. It should be suspectedin any IDDM patient with gastrointestinal symptoms or unexplainedanaemia.