Limitations of ventricular pacing maneuvers to differentiate orthodromic reciprocating tachycardia from atrioventricular nodal reentry tachycardia.

PURPOSE: Various ventricular pacing maneuvers have been developed to differentiate orthodromic reciprocating tachycardia (ORT) from atrioventricular nodal reentry tachycardia (AVNRT). We aimed to evaluate the diagnostic value of ventricular pacing maneuvers in patients undergoing catheter ablation for AVNRT/ORT. METHODS: Sixty patients with supraventricular tachycardia (SVT) undergoing invasive EP study were included (ORT: 31, typical AVNRT: 18, atypical AVNRT: 11). Ventricular overdrive pacing (VOP) and resetting by premature ventricular stimulation (PVS) during SVT were analyzed by 3 independent observers blinded to the ultimate diagnosis. We determined intraclass correlation coefficient (ICC) for interobserver agreement and the diagnostic accuracy of consensual results. RESULTS: Although specificity of all parameters was high (96-100%) for ORT, semi-quantitative parameters of VOP (requiring the recognition of specific ECG patterns) had lower interobserver reliability (ICC: 0.32-0.66) and sensitivity (16.1-77.4%). In contrast, most quantitative measurements of VOP and PVS showed good reproducibility (ICC: 0.93-0.95) and sensitivity (74.2-89.3%), but post-pacing interval after VOP needed correction with AV nodal conduction slowing. False negative results for diagnosing ORT were more common with left free wall vs. right free wall or septal, and slowly vs. fast-conducting septal APs. False positivity was only seen with a bystander, concealed nodo-fascicular/nodo-ventricular (NF/NV) AP in a case of AVNRT. CONCLUSIONS: No single maneuver is 100% sensitive for ORT. Semi-quantitative features have limited reproducibility and all parameters can be misleading in the case of rate-dependent delay during VOP/PVS, ORT circuits remote from the pacing site, or a bystander, concealed NF/NV AP.

Safety profile of endovascular treatment for chronic cerebrospinal venous insufficiency in patients with multiple sclerosis.

PURPOSE: To evaluate the safety of endovascular treatment of chronic cerebrovascular insufficiency (CCSVI) in patients with multiple sclerosis (MS). METHODS: In a 1-year period, 461 MS patients (261 women; mean age 45.4 years, range 21-79) with CCSVI underwent endovascular treatment of 1012 venous lesions during 495 procedures [34 (6.9%) reinterventions]. While balloon angioplasty was preferred, 98 stents were implanted in 76 patients for lesion recoil, restenosis, or suboptimal dilation. The procedures were analyzed for incidences of major adverse events (death, major bleeding, or clinical deterioration of MS), access site complications, procedure-related complications, and procedural safety-related variables (fluoroscopy and contrast times). The complication rates were compared to published data for similar endovascular methods. RESULTS: There were no deaths, major bleeding events, or clinical deterioration of MS. Access site complications included limited groin hematoma (5, 1.0%); there were no arteriovenous fistulas or puncture site infections. Systemic complications included only rare cardiac arrhythmias (6, 1.2%). Procedure-related complications included vein rupture (2, 0.4%), vein dissection (15, 3.0%), acute in-stent/in-segment thrombosis (8, 1.6%), and acute recoil (1, 0.2%); there was no stent migration or fracture or distal embolization. Mean fluoroscopy time was 22.7 minutes, and mean contrast volume was 136.3 mL. CONCLUSION: Endovascular therapy appears to be a safe and reliable method for treating CCSVI. Innovations such as purpose-specific materials and devices are needed, as are case-controlled and randomized data to establish efficacy in ameliorating MS symptoms.