Electrophysiological features of atrial tachyarrhythmias after the creation of a left atrial roof line during catheter ablation of atrial fibrillation

Left atrial roof line (LARL) can prevent the perpetuation of atrial fibrillation (AF) by delineation of the arrhythmogenic substrate, but it may be associated with an increased incidence of atrial tachycardia (AT). This study was performed to evaluate the characteristics and clinical implications of inducible AT after LARL.A total of 139 consecutive patients with AF who underwent catheter ablation were prospectively enrolled in this study. LARL was required to prevent the perpetuation of AF in 98 of 139 patients (71%). LARL significantly reduced the incidence of inducible AF (before versus after: 100% versus 44%, respectively, P < 0.01), whereas it significantly increased the incidence of AT (18% versus 63%, P < 0.01). ATs were observed after LARL in 62 of 98 patients (63%), and these circuits were determined in 99 of 112 stable ATs (88%), including tricuspid isthmus-dependent (n = 35), mitral annulus (n = 22), septal (n = 15), surrounding right pulmonary veins (PVs) (n = 12), coronary sinus (CS) ostium (n = 4), upper loop (n = 4), surrounding left PVs (n = 4), and LA anterior wall (n = 3). Catheter ablation (CA) successfully terminated 111 of 122 stable ATs (91%) during CA. The occurrence of AT after CA was significantly higher in patients with than in those without residual AT (26% versus 2%, P < 0.05).Induced AT with a stable circuit after LARL creation could be mapped, and delineation of the induced AT may lead to a favorable outcome.     

Timing of the restenosis following nitinol stenting in the superficial femoral artery and the factors associated with early and late restenoses

Objectives : We sought to investigate the timing of restenosis and the restenosis factors following nitinol stenting in the superficial femoral artery (SFA). Background : Restenosis following nitinol stenting in the SFA remains unsolved. Methods : We analyzed 742 limbs in consecutive 585 patients who underwent successful endovascular therapy for de novo SFA lesions. Patency was assessed by duplex ultrasonography. Primary patency was defined as treated vessels without restenosis and secondary patency was defined as target vessels reopened by repeat revascularization. Receiver‐operating characteristic (ROC) analysis was performed to delineate the timing of restenosis. Patients were subsequently classified into three groups: no restenosis, early restenosis, and late restenosis. Cox proportional hazard regression analyses were performed to explore the determinants of restenosis in each restenosis group. Results : Primary and secondary patency was 67 and 86% at 6 years, respectively. ROC curves indicated the 369th day was the best cutoff point distinguishing the early (144 limbs) and the late (42 limbs) restenoses. Sustained patency was observed in 556 limbs. After multivariate analysis, cilostazol (P = 0.0007) was negatively associated; female gender (P = 0.0071), diabetes mellitus (P = 0.0428), critical limb ischemia (P = 0.0435), and stent fracture (P = 0.0004) were positively associated with the early restenosis. Trans Atlantic Inter‐Society Consensus II C/D was positively associated with both the early (P = 0.0017) and the late (P = 0.0359) restenoses. Conclusions : Restenosis predominantly occurred within a year following nitinol stenting in the SFA, and the factors associated with the early restenosis were different from those with the late restenosis. © 2011 Wiley‐Liss, Inc.     

A pediatric intramedullary spinal cord tumor with unusual solid‐cystic and papillary features: A case report

Spinal cord tumors are rare in children. We report a novel case of pediatric intramedullary spinal cord tumor with unusual solid‐cystic and papillary features. Clinically, the patient presented at the age of 3 years with motor deficit and urinary incontinence, and MRI demonstrated multilocular cystic lesions in the thoracic spine. Histologically the tumor consisted of solid, sheet‐like components and branching papillary structures, and immunohistochemistry demonstrated positive reactivity for epithelial membrane antigen, cytokeratins (7, AE1/3, CAM5.2), E‐cadherin and transthyretin, and negativity for GFAP, S‐100 protein, synaptophysin and neurofilament. These histological and immunohistochemical findings appeared to be unique, and were not compatible with the features of classical ependymoma or choroid plexus papilloma. The clinical behavior, characterized by relatively rapid tumor regrowth after surgical resection and a relatively high MIB‐1 labeling index, suggest that this tumor might have had moderate malignant potential. This pediatric case appears to be particularly informative with regard to the tumor biology or tumorigenesis of intramedullary spinal cord tumor with unusual solid‐cystic and papillary features.     

Pressure‐guided second‐generation cryoballoon pulmonary vein isolation: Prospective comparison of the procedural and clinical outcomes with the conventional strategy

Background: The utility of pressure waveform analyses to assess pulmonary vein (PV) occlusions has been reported in cryoballoon PV isolation (CB‐PVI) using first‐generation CBs. This prospective randomized study compared the procedural and clinical outcomes of pressure‐guided and conventional CB‐PVI. Methods and Results: Sixty patients with paroxysmal atrial fibrillation underwent CB‐PVI with 28‐mm second‐generation CBs. PV occlusions were assessed either by real‐time pressure waveforms without contrast utilization (pressure‐guided group) or contrast injections (conventional group) and randomly assigned. Before the randomization, 24 patients underwent pressure‐guided CB‐PVIs. In the derivation study, a vein occlusion was obtained in 88/96 (91.7%) PVs among which 86 (97.7%) were successfully isolated by the application. In the validation study, the nadir balloon temperature and total freezing time did not significantly differ per PV between the two groups. The positive predictive value of the vein occlusion for predicting successful acute isolations was similar (93 of 103 [90.2%] and 89 of 98 [90.8%] PVs; P = 1.000), but the negative predictive value was significantly higher in pressure‐guided than angiographical occlusions (14 of 17 [82.3%] vs 7 of 22 [31.8%]; P = .003). Both the procedure (57.7 ± 14.2 vs 62.6 ± 15.8 minutes; P = .526) and fluoroscopic times (16.3 ± 6.4 vs 20.1 ± 6.1; P = .732) were similar between the two groups, however, the fluoroscopy dose (130.6 ± 97.7 vs 353.2 ± 231.4 mGy; P < .001) and contrast volume used (0 vs 17.5 ± 7.7 mL; P < .001) were significantly smaller in the pressure‐guided than conventional group. During 27.8 (5‐39) months of follow‐up, the single procedure arrhythmia freedom was similar between the two groups (P = .438). Conclusions: Pressure‐guided second‐generation CB‐PVIs were similarly effective and as safe as conventional CB‐PVIs. This technique required no contrast utilization and significantly reduced radiation exposure more than conventional CB‐PVIs.     

Glucagon plays an important role in the modification of insulin secretion by leptin

Obese people show marked hyerinsulinemia, but the exact mechanism has not been clarified.?Hyperleptinemia is one of possible candidates, although there is an obvious difference in the effect of leptin on insulin secretion between isolated pancreatic islets and β-cell line.?Since glucagon may modulate the effect of leptin on insulin secretion, we determined the influences of glucagon in the leptin effect on insulin secretion.?The influences of glucagon in the leptin effect on insulin secretion for 10 minutes were determined by using isolated mouse islets and HIT-T 15 cells.?The influences of 3-isobutyl-1- methylxanthine (IBMX), forskolin, and dibutyryl cyclic AMP were investigated in the leptin effect on insulin secretion.?Leptin-inhibited insulin and glucagon secretion in isolated mouse pancreatic islets.?In contrast, leptin stimulated insulin secretion in isolated mouse islets previously incubated with monoclonal anti-glucagon antibodies for 18 hours.?In HIT-T 15 cells, leptin dose-dependently increased insulin secretion, but this effect was attenuated by the addition of glucagon.?The stimulatory effect of leptin on insulin secretion was attenuated by 48 hour pre-incubation with glucagon.?In the presence of 100 mM IBMX, leptin decreased insulin secretion from HIT-T 15 cells.?Leptin also reduced insulin secretion in the presence of 1mM forskolin or 1mM dibutyryl cyclic AMP.?The leptin effects on insulin secretion were affected by the existence of glucagon. Intracellular cyclic AMP concentrations may determine the leptin effects on insulin secretion in pancreatic β-cells.