The use of external, noninvasive pacing for the termination of supraventricular tachycardia in the emergency department setting

STUDY OBJECTIVE: To determine the potential feasibility of external cardiac pacing for the termination of sustained supraventricular tachycardia in the emergency department setting. TYPE OF PARTICIPANTS: Three men and two women (mean age, 34 years) who presented to the ED with a narrow-complex, hemodynamically stable tachycardia that was later proven to be supraventricular in origin. INTERVENTION: Each patient underwent external overdrive pacing using a modified external pacemaker at a pulse amplitude of 120 mA and a rate between 240 and 280 pulses per minute. RESULTS: In four patients, external cardiac pacing was able to successfully terminate the tachycardia without complication. In one patient, the pacemaker was not able to terminate the tachycardia. CONCLUSION: We conclude that external, noninvasive pacing is a feasible means of terminating supraventricular tachycardia in the ED setting.     

Some techniques for solving linear equation systems with guarantee

Methods are described for solving a system of linear equations with error bounds. Rectangular and spherical intervals ofR ⁿ are used combined. The objective is to get guaranteed accuracy with a minimal effort of computing time.     

Thermodynamic magnetization discontinuity between the A and B phases of superfluid3he

We present data for the magnitude of the thermodynamic magnetization discontinuity at the equilibrium A-B transition in superfluid³He, M_AB, over its entire pressure-temperature-magnetic field phase diagram. The data was taken by measuring flux changes in a SQUID pick-up coil, which was calibrated by a novel first-principles technique. We compare our results with those of NMR experiments, and find that the two types of measurements yield different values, and this discrepancy is not the result of thermometry or field errors.     

Hot Photo–Carriers, Excitons, Desorption, and Surface Diffusion in Rare Gas Solids

The dynamics of valence excitations of rare gas solids were studied with time–and spectrally resolved luminescence experiments. From the decay curves of the free–exciton luminescence in solid X _e , information concerning exciton transport and electron–hole recombination was deduced. The peculiar role of excitons stimulating the luminescence of surface centers and of desorption phenomena was analysed in a simple model system (Kr doped solid Ar). From a time–resolved analysis of the luminescence of surface centers, thermally activated lateral diffusion of Kr* metastables on the surface of the Ar host was established.