BackgroundSlow conduction zone in a verapamil‐sensitive reentrant atrial tachycardia originating from atrioventricular annulus is composed of calcium channel–dependent tissue. We examined whether there was a slow potential (SP) at the entrance of the slow conduction zone.Methods and ResultsWe first identified the pacing site from where manifest entrainment and orthodromic capture of the earliest atrial activation site were demonstrated in 40 atrioventricular annulus patients with atrioventricular annulus. Radiofrequency energy was then delivered 2 cm proximal to the earliest atrial activation site in the direction of entrainment pacing site and gradually advanced toward the earliest atrial activation site until atrial tachycardia termination to localize the entrance of the slow conduction zone. Electrogram characteristics were analyzed at successful and unsuccessful ablation sites. During sinus rhythm, SP was observed at all 40 successful sites, but was observed at only 12 unsuccessful sites (P<0.0001). During sinus rhythm, there was no significant difference in electrogram amplitude nor width of atrial electrogram between successful and unsuccessful sites (0.407±0.281 versus 0.487±0.447 mV [P=0.1989] and 37.0±9.2 versus 38.9±8.0 ms [P=0.1773]); however, SP amplitude and width at successful sites were significantly greater than those at unsuccessful sites (0.110±0.049 versus 0.025±0.046 mV [P<0.0001] and 38.8±13.4 versus 8.1±13.2 ms [P<0.0001]). During atrial tachycardia, SP amplitude was significantly attenuated (0.088±0.042 versus 0.110±0.049 mV, P<0.001) and SP width was significantly prolonged (47.8±14.1 versus 38.8±13.4 ms, P<0.0001) at successful sites.Conclusions SP was observed during sinus rhythm at the entrance of the slow conduction zone; however, SP amplitude was attenuated and SP width was prolonged during atrial tachycardia, suggesting that SP reflects the characteristics of calcium channel–dependent tissue involved in atrioventricular annulus reentry circuit.

Background: The impact of intra-atrial conduction delay on the recurrence of atrial tachyarrhythmia after radio frequency catheter ablation (RFCA) has not been fully elucidated. Methods: We retrospectively analyzed 155 AF patients who were sinus rhythm at the start of RFCA. The conduction time from the onset of the earliest atrial electrogram at the high right atrium (HRA) to the end of the latest electrogram at the coronary sinus (CS) during sinus rhythm was defined as HRA-CS conduction time. Pulmonary vein isolation (PVI) was performed followed by linear roof lesion and complex fractionated atrial electrogram (CFAE) ablation until AF termination. We evaluated atrial tachyarrhythmia recurrence 12 months after RFCA. Results: The follow-up data were available for 148 patients. The recurrence of atrial tachyarrhythmia was noted in 28 (18.9%) patients. Atrial tachyarrhythmia recurrence patients had longer HRA-CS conduction times (151.3 ± 22.1 ms vs 160.1 ± 32.6 ms, p = .017). The patients were divided into the long or short HRA-CS conduction time group. The Kaplan-Meier analysis revealed that the long HRA-CS conduction time group held a higher risk of atrial tachyarrhythmia recurrence (log-rank test, p = .019). The multivariable Cox hazard analysis revealed that a long HRA-CS conduction time was a significant risk factor for the recurrence of atrial tachyarrhythmia, despite a long AF duration, persistent AF, and larger left atrial diameter (LAD) were not statistically significant. Conclusions: The HRA-CS conduction time was the primary influencing factor that predicted the recurrence of atrial tachyarrhythmia after catheter ablation.

Background The clinical implication of vascular endothelial dysfunction in patients with atrial fibrillation (AF) remains unclear. This study aimed to elucidate the correlation between changes in vascular endothelial function assessed by reactive hyperemia‐peripheral arterial tonometry and the effect of sinus rhythm restoration after catheter ablation (CA) for AF. Methods and Results Consecutive 214 patients who underwent CA for AF were included in this single center, retrospective study. The natural logarithmic transformed reactive hyperemia‐peripheral arterial tonometry index (LnRHI) of all patients was measured before CA as well as 3 and 6 months after CA. LnRHI in sinus rhythm was significantly higher than that in AF before CA. Multivariate logistic regression analysis revealed that the presence of AF was an independent risk factor for lowering of LnRHI (odds ratio, 4.092; P =0.002) before CA. The LnRHI was significantly improved 3 and 6 months after CA in patients without AF recurrence. Multivariate Cox hazard analysis revealed that changes in LnRHI from before to 3 months after CA independently correlated with recurrence of AF (hazard ratio, 0.106; P =0.001). Receiver operating characteristic analysis showed the decrease in LnRHI levels from before to 3 months after CA as a significant marker that suspects AF recurrence (area under the curve, 0.792; log‐rank test, P <0.001). Conclusions The presence of AF was independently correlated with the impaired vascular endothelial function assessed by the reactive hyperemia‐peripheral arterial tonometry. Long‐term sinus rhythm restoration after CA for AF might contribute to the improvement of vascular endothelial function, which may reflect the nonrecurrence of AF.

BackgroundAlthough vein stenting is popular for treatment for venous thromboembolism due to mechanical compression, some cases are forced to avoid inserting align agents because of immunodeficiency.Case presentationAn 82-year-old man with left extremity redness and swelling presented to a hospital for a medical evaluation. The patient was immunodeficient because of the adverse effects of his treatment for Castleman’s disease. A contrast-enhanced computed tomography scan revealed a venous thromboembolism in inferior vena cava and the left lower extremity. Magnetic resonance venography showed that the iliac artery was compressing the iliac vein. We were reluctant to place a stent in the iliac vein has because of the patient’s immunodeficient status. Three months of treatment using single-dose edoxaban (30 mg daily) resulted in complete resolution of the thrombus. This is the first report demonstrating that single-dose edoxaban without acute-phase parenteral anticoagulation is effective in the treatment of iliac vein compression.ConclusionsA single-dose direct oral anti-coagulant without acute-phase parenteral anticoagulation is effective for mechanical compression

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