Paroxysmal Atrial Fibrillation Maintained by Nonpulmonary Vein Sources Can Be Predicted by Dominant Frequency Analysis of Atriopulmonary Electrograms

Introduction: Increasing evidence suggests that high-frequency excitation in the pulmonary vein (PV) plays a dominant role in the maintenance of paroxysmal atrial fibrillation (AF). However, in a certain population of patients, AF remains inducible after PV isolation (PVI). We sought to clarify whether dominant frequency (DF) analysis of atriopulmonary electrograms can predict paroxysmal AF maintained by non-PV sources.
Methods and Results: Sixty-one patients with paroxysmal AF (aged 59 ± 12 years) were studied. Before PVI, bipolar electrograms during AF were recorded simultaneously from three PV ostia, the coronary sinus (CS), and the septum and free wall of the right atrium (RA). DF was obtained by fast Fourier transform (FFT) analysis. AF was rendered noninducible after PVI in 39 of the 61 patients (noninducible group), but was still inducible in the remaining 22 (inducible group). Among the six recording sites, the highest DF was documented in the PV in all of the patients in the noninducible group; the maximum DF among the three PVs (PV-DF_max) was higher than that among the CS and two RA sites (atrial DF_max; 7.2 ± 1.0 Hz vs 5.8 ± 0.7 Hz, P < 0.0001). In contrast, the highest DF was documented in the CS or RA in 45.5% of the patients in the inducible group; PV-DF_max was comparable with atrial DF_max (6.6 ± 0.8 Hz vs 6.6 ± 0.6 Hz). AF inducibility after PVI was predicted by a PV-to-atrial DF_max gradient of <0.5 Hz, with a sensitivity of 90.9% and a specificity of 89.7%.
Conclusion: Paroxysmal AF maintained by non-PV sources can be predicted by the PV-to-atrial DF gradient.     

Association of mutations in the core promoter and precore region of hepatitis virus with fulminant and severe acute hepatitis in Japan

It was recently reported that mutations in the precore and core promoter region of hepatitis B virus (HBV) are associated with fulminant hepatitis. The aim of this study was to investigate the association of mutations in the precore and core promoter region of HBV with fulminant and severe acute hepatitis. We studied Japanese patients with acute HBV infection, including seven patients with fulminant hepatitis, 12 with severe acute hepatitis and 41 with acute self-limited hepatitis. The presence of HBV mutants was examined by using a point mutation assay to detect a G to A transition at position 1896 in the precore region and an A to T transition at position 1762 and a G to A transition at position 1764 in the core promoter region. Significant differences in the proportion of mutations in the precore or core promoter region were present between patients with fulminant hepatitis and self-limited acute hepatitis (7/7 (100%) vs 4/41 (9.8%), P < 0.01) and between severe acute hepatitis and self-limited acute hepatitis (6/12 (50.0%) vs 4/41 (9.8%), P < 0.01). The frequency of mutation increased proportionately with the severity of disease in patients with acute HBV infection. Fulminant hepatitis B in Japan is closely associated with mutations in the core promoter and precore gene of HBV. Point mutation assays for HBV precore and core promoter analysis may be useful to predict the outcome of liver disease in patients with acute HBV infection.