Vitamin B6 in the treatment of the premenstrual syndrome–a review

Summary. A search of the literature yielded 12 controlled trials on vitamin B6 in the treatment of the premenstrual syndrome. These are discussed with emphasis on methodological aspects. A major drawback of the trials is the limited number of patients included. The existing evidence of positive effects of vitamin B6 is weak, and some well-designed trials with positive results would be needed to change this view.     

Early Assessment of Biophysical Parameters Predicts Lesion Formation During RF Energy Delivery In Vitro

Background: There is no currently available technology to accurately predict ablation lesion size within seconds of onset of delivery of radiofrequency (RF) energy. Methods: Changes in several biophysical characteristics of cardiac tissue in vitro within 5–15 seconds of the onset of RF energy were evaluated to predict lesion formation at 120 seconds. RF energy was applied with a 50% duty cycle to measure heating and cooling behavior of the electrode temperature sensor. Changes in impedance, phase angle, and the resulting resistance and capacitance, power, and electrode temperature variation during RF ablation were analyzed. Results: A combination of electrical‐based parameters measured online as early as 5, 10, and 15 seconds after onset of RF energy in vitro was found to explain 63, 75, and 76% of variability (R²) of lesion volume. These correlations were better than any single parameter, particularly impedance and target temperature. Conclusions: A combination of electrical‐based parameters provides better correlation with lesion formation than a single parameter and may be useful to predict lesion size during RF ablation in vivo. These parameters appear to represent changes in the tissue during heating. (PACE 2010; 33:1082–1088)     

Effects of Intrapericardial Sotalol and Flecainide on Transmural Atrial Electrophysiology and Atrial Fibrillation

Introduction: Intrapericardial (IPC) delivery of antiarrhythmic agents is an appealing idea to increase the therapeutic width and reduce side effects of drugs, particularly in the thin atria. The aim of this study was to determine the effects of IPC versus intravenous (IV) d,l-sotalol and flecainide infusion on transmural atrial electrophysiology and sustained atrial fibrillation (AF) in the goat.
Methods and Results: Effects of IPC and IV sotalol and flecainide infusion on epi- and endocardial atrial electrophysiology, ECG, and tissue drug concentrations were studied in goats without and with persistent AF (>24 hours). Epicardial atrial refractory period (AERP, bcl 400 ms) increased after 120 minutes of 1 mg/kg/hour IPC sotalol with 61 ± 8 ms (P = 0.02), whereas the endocardial AERP was not affected. One mg/kg/hour IPC flecainide increased the epicardial pacing threshold and the epicardial AERP with 4 ± 0.5 mA (P = 0.003) and 33 ± 11 ms (P = 0.05), respectively. Endocardial values were unchanged. Marked ST-elevations in the precordial ECG leads were observed after IPC flecainide. In the AF group, IPC drugs did not prolong AF cycle length to a greater extent than IV delivery. The number of cardioversions was not different between the two delivery routes. A steep transmural drug concentration gradient after IPC sotalol and flecainide was observed in all heart chambers.
Conclusion: IPC sotalol and flecainide infusion in goats markedly affects epicardial atrial electrophysiology. IPC delivery, however, does not prolong AFCL or terminate AF to a greater extent than IV infusion. This suggests that the perpetuation of AF is not dominated by the epicardial and sub epicardial atrial layers.