Remote-controlled catheter ablation of accessory pathways: results from the magnetic laboratory.

AIMS: This study evaluates feasibility, safety, and efficacy of magnetic remote-controlled accessory pathway (AP) ablation. METHODS AND RESULTS: The novel magnetic navigation system (MNS) (Niobe, Stereotaxis) creates a steerable magnetic field (0.08 T) controlling the distal magnetic tip of an ablation catheter. In conjunction with a catheter advancer system (Cardiodrive, Stereotaxis) remote catheter ablation is enabled. Conventional electrophysiology study identified AP conduction in 59 patients (37 males, 36+/-14 years, 60 APs). First generation 1-magnet tip (1-M) (group I, n=18), second generation bipolar 3-magnet tip (3-M) (group II, n=27), and third generation quadripolar 3-magnet tip catheters (3-M quad.) (group III, n=14) were used for magnetic remote-controlled ablation. Successful AP ablation was achieved in 67% (group I), 85% (group II), and 92% (group III). A significant decrease of median [IQR: Q1-Q3] fluoroscopy time and dosage was observed: 21.2 [12.1-33.8] min, 1110 [395-3234] microGym2 (group I); 6.5 [4.4-15.4] min, 290 [129-489] microGym2 (group II), and 4.9 [3.4-8.0] min, 129 [74-270] microGym2 (group III). Mean procedure time (217+/-67 min; 182+/-68 min, and 172+/-90 min) significantly decreased in group III. Median number [Q1-Q3] of radiofrequency current applications in groups I, II, and III was 4 [2-9], 4 [2-6], and 2 [2-4], respectively. No complications occurred. CONCLUSION: Remote AP ablation is safe and feasible using the novel MNS. Introduction of the 3-magnet quadripolar ablation catheter significantly improved the efficacy of the procedure.     

Psychological, biological and health behavior predictors of blood pressure changes in middle-aged women.

A long-standing hypothesis is that feelings of anger and anxiety increase the risk for essential hypertension. Most studies examining this hypothesis have been cross-sectional in design or undertaken with men only. We tested this hypothesis along with determination of the other behavioral and biological predictors of increases in systolic (SBP) and diastolic (DBP) blood pressure from baseline to a follow-up examination 3 years later in a prospective study of 468 middle-aged women whose blood pressure at the baseline examination was less than 140/90 mmHg. Analyses showed that increases in the Spielberger Trait Anger Scale between the baseline and 3-year follow-up examination, as well as Framingham Tension scores (a measure of anxiety) at baseline, independently predicted an increase in SBP (P less than 0.01). Other factors that independently predicted an increase in SBP were baseline fasting insulin, parental history of hypertension and increases in body mass index and in alcohol intake across the 3 years of follow-up. Increases in the Spielberger Trait Anger Scores independently predicted increases in DBP (P less than 0.02), as did black race, increases in body mass index and hematocrit and decreases in potassium intake. Although menopausal status and hormone replacement therapy were unrelated to changes in blood pressure, postmenopausal women on hormone replacement therapy did show significant increases in DBP in the univariate analysis. Anxiety at baseline, along with parental history of hypertension, baseline fasting insulin and baseline body mass index, predicted a later onset of hypertension, i.e. on pharmacologic treatment for hypertension, in the univariate analysis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Peripheral Blood Lymphocyte Surface Antigen Expression and Prognosis in Myeloma: Australian Leukaemia Study Group Study

The Australian Leukaemia Study Group myeloma study (MM1) aimed to determine the prognostic significance of clinical and immunophenotypic markers in patients with multiple myeloma. All patients were treated with standard dose melphalan and prednisone. Seventy-four patients were entered and the median survival was 27 months. Serum beta 2-microglobulin (βM) and albumin levels were the only significant clinical factors influencing survival (p = 0.007 and p = 0.008, respectively). Patients with raised levels of CD38+ lymphocytes at presentation had a significantly shorter survival than patients with normal levels (p = 0.01, logrank test, median 19 months vs 33 months). CD38 antigen expression was independent of β2M but patients with raised levels of CD38 had significantly lower levels of albumin than patients with normal levels (p = 0.001) which may explain their poorer survival. Salmon and Durie stage was not associated with antigen expression. No other B-cell antigens (CD10, CD19, CD20, CD21, CD22, CD23, FMC1 or FMC7) or plasma cell antigens tested (PCA-1) were found to be associated with prognosis. Patients who achieved plateau phase had a better prognosis than those who did not (p = 0.04 in a landmark analysis). Patients who achieved plateau phase following an objective response appeared to have a better prognosis than those who were in plateau phase at presentation (p = 0.09 in a landmark analysis). Light chain isotype suppression (LCIS) was not associated with a significant survival advantage and did not correlate with any known prognostic indicator. We conclude that phenotypic analysis of peripheral blood lymphocytes for CD38 antigen at diagnosis may be useful as a prognostic indicator in patients with myeloma.     

Pulse oximetry during minor oral surgery with and without intravenous sedation.

This study investigated the levels of oxygen saturation and pulse rates of patients undergoing minor oral surgery under local analgesia, with (20 patients) or without (20 patients) intravenous sedation with midazolam. The results indicated that a statistically significant fall in arterial blood oxygenation of 1% to 2%, as measured by pulse oximetry, followed midazolam administration; however, this was physiologically insignificant. Both groups showed a similar postoperative small fall in oxygen saturation. Transient episodes (24 to 36 seconds) of physiologically significant mild hypoxia occurred during breath holding, but this condition was readily corrected by encouraging patients to breathe deeply. Midazolam had a small but significant calming effect on the higher preoperative pulse rates exhibited by anxious patients, but this effect was not sustained during the operating period. Both sedated and unsedated patients showed episodes of tachycardia that could have significance for patients with cardiac disease.     

Computed tomography and plain radiography in experimental fracture healing

We evaluated the relative contribution of plain radiographs and computed tomography to the assessment of fracture healing under experimental circumstances. In 15 sheep, we performed midshaft femoral osteotomies and internal fixation of the resultant segmental fractures. Radiographs were obtained preoperatively and immediately postoperatively. Animals were sacrificed at 3 weeks, 6 weeks, 12 weeks, 24 weeks, and 36 weeks after surgery, and the femoral specimens radiographed. After removal of the internal fixation devices, computed tomographic scans of the specimens were performed.By 3 weeks, callus was visible, but at 6 weeks, a trabecular pattern in the callus was seen on plain films but not on computed tomography. There was progressive organization of the callus on both studies. At 24 weeks, computed tomography demonstrated fracture lines not seen due to overlying callus on plain films and also more accurately showed incomplete union. By 36 weeks, healing was essentially complete according to both modalities, although there still were small gaps in the callus detectable on computed tomography but not on plain films.Computed tomography may be of value in the evaluation of fractures of long bones in those cases in which clinical examination and plain radiographs fail to give adequate information as to the status of healing.