Junctional rhythm during cryoablation for typical atrioventricular nodal reentrant tachycardia.

INTRODUCTION: Cryoablation is being used as an alternative to radiofrequency (RF) ablation for atrioventricular nodal reentrant tachycardia (AVNRT) owing to the lower risk of atrioventricular block (AVB) compared to RF ablation. Junctional rhythm often occurs during successful application of RF ablation for AVNRT. In contrast, junctional rhythm has rarely been reported to occur during cryoablation. This retrospective study evaluated the characteristics of junctional rhythm during cryoablation for typical AVNRT. METHODS AND RESULTS: This retrospective study included 127 patients in whom successful cryoablation of typical AVNRT was performed. Patients diagnosed with atypical AVNRT were excluded. Junctional rhythm appeared during cryofreezing in 22 patients (17.3%). These junctional rhythms appeared due to cryofreezing at the successful site in the early phase within 15 s of commencement of cooling. Transient complete AVB was observed in 10 of 127 patients (7.9%), and it was noted that atrioventricular conduction improved immediately after cooling was stopped in these 10 patients. No junctional rhythm was observed before the appearance of AVB. No recurrence of tachycardia was confirmed in patients in whom junctional rhythm occurred by cryofreezing at the successful site. CONCLUSION: Occurrence of junctional rhythms during cryoablation is not so rare and can be considered a criterion for successful cryofreezing. Furthermore, junctional rhythm may be associated with low risk of recurrent tachycardia.

Catheter ablation of atrial tachyarrhythmias after a Maze procedure: A single center experience.

Significant recurrence of atrial tachyarrhythmias are observed after the surgical Cox Maze procedure (CMP). We retrospectively enrolled 11 consecutive patients who had atrial tachyarrhythmias (ATAs) that recurred after a biatrial CMP and underwent catheter ablation. Information including the site of any incomplete lesions and the etiology of the clinical ATAs was shared with the surgical team as feedback. In a total of 11 patients, 12 clinical ATAs were identified. They consisted of 2 atrial fibrillations and 10 atrial tachycardias (ATs). In 6 patients, the CMP was performed after the beginning of this investigation. In a total of 10 ATs, we diagnosed 5 mitral annular flutters, 2 roof-dependent flutters, 1 pulmonary vein (PV)-reentrant AT, and 1 localized reentrant AT. A total of 6 patients had reconnected perimitral block lines. PV reconnections were observed in 3 and posterior wall (PW) residual conduction was also observed in 3 cases. However, no residual conduction of the pulmonary vein isolation (PVI) and only 1 residual conduction of the PW were observed in 5 patients who underwent their index surgery after the beginning of this investigation. This fact may implicate that sharing the information from the electrophysiological study of postsurgical ATAs with the surgical team may contribute to the refinement of the CMP in each facility. .

Rapid mapping and differentiation in ventricular outflow tract arrhythmia using non-contact mapping.

PURPOSE: Ventricular outflow tract arrhythmias (VOTAs) can be successfully treated by catheter ablation. However, it is sometimes difficult to differentiate the origin of VOTAs between the right ventricular outflow tract (RVOT) and the other sites, leading to a long fluoroscopy time and unnecessary radiofrequency applications. This study aimed to clarify distinguishable characteristics of the propagation pattern obtained from non-contact mapping (NCM) for VOTA ablation. METHODS: Consecutive 45 patients with VOTAs who underwent catheter ablation using the NCM system were included in this study. We analyzed an isopotential map on three-dimensional geometry of the RVOT obtained from the virtual unipolar electrograms (VUEs) and assessed mapping data of the isopotential area with an initial negative VUE of -1 mV. RESULTS: Successful ablation was achieved from the endocardial RVOT in 34 patients (RVOT group) and the non-RVOT in 11 (non-RVOT group). Major and minor axis diameters of the isopotential area did not significantly differ between the two groups. However, a ratio of major/minor axis diameter was greater in the RVOT group (1.9 ± 0.1 versus 1.3 ± 0.1; P < 0.001). In addition, the propagation velocity defined as an increase of the isopotential area per millisecond was significantly slower in the RVOT group (2.2 ± 0.4 versus 4.2 ± 0.7 mm2/ms; P = 0.02). CONCLUSIONS: The isopotential area of VOTAs originating from the RVOT, as compared to the other sites, spread more elliptically and slowly. The propagation pattern obtained from NCM can provide useful information and efficient strategy for VOTA ablation.

Wax ester-like compounds as biosurfactants produced by Dietzia maris from n-alkane as a sole carbon source.

The hydrocarbon-degrading bacterium Dietzia maris WR-3 was isolated from a consortium comprising ammonia-oxidizing and denitrifying bacteria derived from marine sediments. Here, we examined biosurfactant production by strain WR-3 when cultured using several different carbon (D-glucose, n -decane, n -hexadecane, motor oil, olive oil, and rapeseed oil) and nitrogen (NH(4) )(2) SO(4) , NaNO(3) , yeast extract, and polypeptone) sources as growth substrates. Strain WR-3 was able to grow and reduce the surface tension of culture broth to 31±1.0 mN m(-1) when cultured using n -hexadecane and nitrate ions. The surface-active compounds produced by strain WR-3 were extracted and analyzed by thin layer chromatography. Moreover, the main components in the extract were further purified and subjected to gas chromatography/mass spectrometry (GC/MS). From the analysis, the surface-active compounds were tentatively identified as wax ester-like compounds, which were synthesized from the degradation process of n -alkane. The production of surface-active compounds by strain WR-3 promoted attachment of cells to hydrocarbon droplets via increased cell hydrophobicity, thus allowing enhanced degradation of water immiscible substrates. As Dietzia spp. can grow and produce wax esters from the degradation process of hydrocarbons, these marine bacteria are potentially useful for the bioremediation of hydrocarbon-contaminated environments.

Autolysis of Porphyromonas gingivalis is accompanied by an increase in several periodontal pathogenic factors in the supernatant.

Porphyromonas gingivalis autolyzes in the culture media. To examine in more detail the molecular components of the autolysate, two-dimensional gel electrophoresis was performed. Many protein spots varied both in number and volume. One of these spots included Arg-gingipain (Rgp) as determined by N-terminal amino acid sequencing. Corresponding to the increase in spot volume, Rgp activity also increased during autolysis. The results of this study suggested that Rgp and other proteins in the P. gingivalis autolysate may be involved with the prolongation of periodontal disease, even after the death of P. gingivalis cells.