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Pacing threshold is affected by many factors. A pacing system able to confirm capture at each beat and automatically adjust its output close to the actual pacing threshold is highly desirable. This study evaluates the safety and efficacy of the Autocapture function of the Pacesetter Microny SR+. One hundred thirteen patients were recruited from 16 centers in 7 European countries and followed up for 1 year. All pacemakers were implanted with Pacesetter's low polarization, bipolar leads. The key feature of Autocapture is the immediate delivery of a 4.5 V safety backup pulse 62.5 ms after any ineffective ongoing low output pulse. Holter recordings confirmed total reliability of this feature without any exit block. The measured evoked response (ER) signal was stable over time. Acute and chronic pacing thresholds measured by VARIO and Autocapture tests correlated (r > 0.79) over the period of the study. The incidence of backup pulses was 1.1% during pacing. With Autocapture programmed ON, the overall total current consumption was 4.1 microA for VVI and 5.0 microA for VVIR pacing. This study proved that the Autocapture safely and reliably regulates the pacemaker's output according to the prevailing threshold thus providing maximum patient safety and prolonging service life.

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The identification of hydrologically “homogeneous” regions is a primary step in many regional flood frequency techniques. Although statistical procedures for identifying homogeneous regions abound in the literature, there has been relatively little effort directed toward the identification of the physical and climatic basin characteristics that cause similarity in standardized flood peak distributions. We use regional flood peak and basin characteristics data for 104 basins in southeastern Australia to investigate the physical and climatic factors associated with the statistical distributions of flood peaks; the degree of geographical coherence of homogeneous regions; and the extent to which information on flood peak statistics is encapsulated by the physical and climatic characteristics of basins that are commonly used in regionalization studies. Our results show that (1) membership of a particular homogeneous region is determined largely by a combination of climatic characteristics that is related to runoff generation; (2) supergroups consisting of sites within aggregated homogeneous regions that have reasonably similar flood responses show some degree of spatial coherence; and (3) the basin characteristics that influence regional homogeneity can be identified despite the use of indices that smooth spatial and temporal variability.