Wei Wei1, Caihua Sang2, Sulin Zheng3, Roderick Tung1,4, Xunzhang Wang1,5, Yumei Xue1, Yuanhong Liang1, Shangming Song6, Tongbao Liu6, Deyong Long2, Yang Liu1, Jianzeng Dong2, Changsheng Ma7, Shulin Wu8. 1. Department of Cardiology, Guangdong Provincial People's Hospital & Guangdong Academy of Medical Sciences, No. 96, Dongchuan Road, Guangzhou, 510080, Guangdong Province, People's Republic of China. 2. Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Road, Chaoyang District, Beijing, 100029, People's Republic of China. 3. The First People's Hospital of Shunde, Shunde Hospital of Southern Medical University, Foshan, Guangdong Province, People's Republic of China. 4. The University of Chicago Medicine, Center for Arrhythmia Care, Pritzker School of Medicine, Chicago, IL, 60637, USA. 5. Heart Institute, Cedars Sinai Medical Center, Los Angeles, CA, USA. 6. Shandong Provincial Hospital, Jinan, Shandong Province, People's Republic of China. 7. Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Road, Chaoyang District, Beijing, 100029, People's Republic of China. chshma@vip.sina.com. 8. Department of Cardiology, Guangdong Provincial People's Hospital & Guangdong Academy of Medical Sciences, No. 96, Dongchuan Road, Guangzhou, 510080, Guangdong Province, People's Republic of China. dr_shulinwu@126.com.
Abstract
PURPOSE: To clarify the electrophysiological mechanism of supra-ventricular tachycardias (SVT) with concealed nodo-ventricular (NV) fibers. METHODS: We studied the intra-cardiac electrograms during electrophysiological study (EPS) of three cases of SVT which concerned concealed NV fibers. Electrophysiological maneuvers including right ventricular apex entrainments, RS2 stimuli, adenosine triphosphate injection and so on were done for differential diagnosis before ablation. RESULTS: Among these patients, one had atrio-ventricular nodal reentrant tachycardia (AVNRT) with a bystander NV fiber; the other 2 had NV fiber mediated orthodromic reentrant tachycardias (NVRT). VA dissociation was observed during SVT in all 3 cases with an antegrade His bundle conduction sequence. Ventricular stimulation at His refractory period reset the H-H intervals and the V-V intervals sequentially, suggesting the existence of a retrogradely conductive accessory pathway. Adenosine injection could terminate these tachycardias. The cycle length of an NVRT prolonged during the status of functional right bundle branch block, suggesting that the fiber located on the right side. Multiple QRS fusion morphologies during ventricular entrainments or ventricular stimulation at His refractory period at a fixed position could be observed in these cases. CONCLUSIONS: Concealed NV fibers can either mediate orthodromic reentrant tachycardia or be a bystander of AVNRT. V-A dissociation usually occur during such SVTs. Dissociation of H and V due to entrainment of right ventricular apex is a newly discovered maneuver to differentiate AVNRT from NVRT.
PURPOSE: To clarify the electrophysiological mechanism of supra-ventricular tachycardias (SVT) with concealed nodo-ventricular (NV) fibers. METHODS: We studied the intra-cardiac electrograms during electrophysiological study (EPS) of three cases of SVT which concerned concealed NV fibers. Electrophysiological maneuvers including right ventricular apex entrainments, RS2 stimuli, adenosine triphosphate injection and so on were done for differential diagnosis before ablation. RESULTS: Among these patients, one had atrio-ventricular nodal reentrant tachycardia (AVNRT) with a bystander NV fiber; the other 2 had NV fiber mediated orthodromic reentrant tachycardias (NVRT). VA dissociation was observed during SVT in all 3 cases with an antegrade His bundle conduction sequence. Ventricular stimulation at His refractory period reset the H-H intervals and the V-V intervals sequentially, suggesting the existence of a retrogradely conductive accessory pathway. Adenosine injection could terminate these tachycardias. The cycle length of an NVRT prolonged during the status of functional right bundle branch block, suggesting that the fiber located on the right side. Multiple QRS fusion morphologies during ventricular entrainments or ventricular stimulation at His refractory period at a fixed position could be observed in these cases. CONCLUSIONS: Concealed NV fibers can either mediate orthodromic reentrant tachycardia or be a bystander of AVNRT. V-A dissociation usually occur during such SVTs. Dissociation of H and V due to entrainment of right ventricular apex is a newly discovered maneuver to differentiate AVNRT from NVRT.