Search

Background: Terminal P-wave inversion in lead V1 representing left atrial overload has been considered a precursor of atrial fibrillation (AF). Objective: The purpose of this study was to determine whether this P-wave morphologic characteristic can predict the development of AF. Methods: Digital analysis of 12-lead ECGs was performed to enroll patients with P terminal force ≥0.06 s × 2 mm in lead V1 from among a database of 308,391 ECG recordings. The prognostic value of ECG characteristics for developing AF was determined. Results: A total of 78 patients (mean age 52 ± 19 years) with left atrial overload were chosen from among 102,065 patients in the database. During mean follow-up of 43 months, 15 (19%) patients developed AF (AF group) versus 63 (81%) patients who did not (non-AF group). No significant difference was noted between the AF and non-AF groups with regard to the area, duration, and amplitude of the P-wave terminal portion in lead V1. In contrast, the area, duration, and amplitude of the P-wave initial portion in the same lead were significantly greater in the AF group than in the non-AF group (114.6 ± 73.0 μV × ms vs 73.1 ± 59.3 μV × ms, 42.2 ± 12.4 ms vs 35.7 ± 10.1 ms, and 94.0 ± 39.9 μV vs 68.8 ± 49.4 μV, respectively; P <.05 for each). Multivariate analysis confirmed that the area of the P-wave initial portion was independently associated with the development of AF (hazard ratio 4.02, 95% confidence interval 1.25–17.8; P = .018). Conclusion: P-wave initial portion in lead V1 was an independent risk stratifier of AF development in patients with marked left atrial overload. [Copyright &y& Elsevier]

Abstract: Crystal structure of homologous compounds, Zn3In2O6, Zn4In2O7, Zn5In2O8, Zn7In2O10, and In2O3 were refined by X-ray Rietveld analysis. Band structures of the homologous compounds were evaluated by first-principle calculation (Cambridge Serial Total Energy Package, CASTEP), using the structural data obtained from the Rietveld analysis. According to the results of CASTEP calculations, a sharp cut-off at the Fermi level could be observed when In3+ preferentially occupies the tetrahedral site (Zn3In2O6(4)) or the trigonal bipyramid site (Zn3In2O6(5)) in the (InZn k )O k+1 + layers. The cut-off at the Fermi level could not be observed when In3+ and Zn2+ are totally disordered at these sites. Electronic structure calculation suggested that Zn3In2O6(4) is a good conductor and that Zn3In2O6(5) is a poor conductor. Results of geometry optimization indicate that the formation enthalpy of Zn3In2O6(4) was lower than that of Zn3In2O6(5). Considering the electronic structure and the formation enthalpy, Zn3In2O6(4) in which In3+ in the (InZn k )O k+1 + layer occupies the tetrahedral site preferentially, is likely to be the favored structure. [Copyright &y& Elsevier]