Comparison of Threshold Values Between Steroid and Nonsteroid Unipolar Memhrane Leads

The aim of this study was to evaluate whether steroid membrane leads can reduce pacing thesholds and thereby save energy as compared to nonsteroid membrane leads. The study was a random sample, double blind test consisting of 90 patients between 49–94 years of age admitted to seven hospitals in Europe for pacemaker implantation. The two leads compared in this study had contoured activated carbon tips covered with ion exchange membranes. The leads were identical except that 30 μg of dexa-methasone was dissolved in the ion exchange membrane of one of the leads. Normal lead implant procedures were used. Follow-up procedures were conducted at 2 weeks and 1,3,6, and 12 months after lead implantation. The pulse generator was programmed to an amplitude of 2.5 or 5 V and a duration of 0.5 msec. The stimulation threshold was measured using the VARIO function. The threshold was measured a total of three times in order to determine the presence of microdislocations. At the 2- and 4-week follow-ups, the stimulation threshold was significantly lower for the steroid leads than for the membrane leads without steroid (0.54 ± 0.19 vs 0.76 ± 0.25 V, P = 0.0005; and 0.59 ± 0.19 vs 0.74 ± 0.26 V, P = 0.005), but after 3 months, the threshold values were almost the same for both leads.     

Direct Current Application: Easy Induction of Ventricular Fibrillation for the Determination of the Defibrillation Threshold in Patients with Implantable Cardioverter Defibrillators

For the determination of the defibrillation threshold, the induction of ventricular fibrillation is mandatory. However, in severely damaged hearts it is sometimes difficult to induce ventricular fibrillation by rapid stimulation or alternating current. Only rapid nonclinical ventricular tachycardias may result, and their cardioversion threshold may be different from the defibrillation threshold. Therefore, it was the purpose of this study to test the potential of direct current (DC) application to rapidly induce ventricular fibrillation in patients with an implanted cardioverter defibrillator. The defibrillation threshold had to be determined in 13 patients (9 with coronary heart disease, 4 with dilative cardiomyopathy, ejection fraction 35%) during and 2 weeks after the implantation of a cardioverter defibrillator. DC was applied 37 times by a commercially available 9-V DC battery via a bipolar catheter for about 3 seconds. Ventricular fibrillation was induced 23 times (62%) and rapid nonclinical ventricular tachycardias were induced six times (16%). In one patient clinical ventricular tachycardia was observed. In seven instances (19%) sinus rhythm remained. In 12 of the 13 patients, ventricular fibrillation could be induced by DC. Thus, the induction of ventricular fibrillation by DC application may serve as an additional tool to induce ventricular fibrillation, determining the defibrillation threshold in implantable cardioverter defibrillator patients.     

MONOCLONAL ANTIBODY WGM1 DIRECTED AGAINST PROTEINASE 3: AN IMMUNOHISTOCHEMICAL MARKER FOR NAPHTHOL ASD CHLOROACETATE

Enzyme histochemistry for naphthol ASD chloroacetate (NASDCA, ‘Leder's stain’) is used to identify the granulocyte lineage ranging from promyelocytes to mature neutrophils and is an additional tool for the characterization of leukemias. We demonstrated for the first time that NASDCA activity can be detected by routine immunohistochemistry and immunocytochemistry using the monoclonal antibody WGM1 directed against proteinase 3 (PR3; synonyms: Wegener's autoantigen, myeloblastin). Immunohisto- and immunocytochemical staining with WGM1 against PR3 and enzyme histochemistry for NASDCA produced identical staining patterns in normal myelomonocytic cells and cells of myeloid leukemia. This was additionally proven by double immunostainings. We have also shown that PR3 is one of the specific proteinases responsible for hydrolysis of NASDCA.     

Heparin‐induced non‐necrotizing skin lesions: rarely associated with heparin‐induced thrombocytopenia

See also Warkentin TE, Linkins L‐A. Non‐necrotizing heparin‐induced skin lesions and the 4T’s score. This issue, pp 1483–. Summary. Background: Recently, there has been an increasing number of reports regarding adverse skin reactions to subcutaneous heparin administration. Case series have implied that heparin‐induced skin lesions are predominantly associated with life‐threatening heparin‐induced thrombocytopenia (HIT) in at least 22% of patients. Skin lesions, therefore, have been included in clinical scores for HIT. Objectives: To determine the association of heparin‐induced skin lesions with HIT. This would have a pivotal impact on further anticoagulatory management in patients with heparin‐induced skin lesions. Patients/Methods: In our observational cohort study, 87 consecutive patients with heparin‐induced skin lesions (85 occurring during low‐molecular‐weight heparin administration) were evaluated using a standardized internal protocol, including HIT diagnostics (heparin‐platelet factor 4‐ELISA, heparin‐induced platelet activation assay), platelet count monitoring, clinical/sonographical screening for thrombosis, skin allergy testing and, if necessary, histology. Results: None of the observed heparin‐induced skin lesions was due to HIT; all lesions were caused by delayed‐type IV‐hypersensitivity reactions (DTH) instead. Even the cutaneous reaction in one patient with concomitant HIT could be classified histologically as DTH reaction, amounting to an association of heparin‐induced skin lesions and HIT in 1.2% (1/87; 95% confidence interval, 0.00–0.06). Conclusion: Heparin‐induced skin lesions associated with use of low‐molecular‐weight heparins do not seem to be strongly associated with a systemic immunologic reaction in terms of HIT and might rather be due to DTH reactions than due to microvascular thrombosis. Hence, we propose refining existing pretest probability scores for HIT, unless underlying causes have been clarified.