Kantharia Bharat K, Shah Arti N
Professor of Medicine, The University of Texas-Health Science Center at Houston, 6431 Fannin Street, Suite MSB 1.246, Houston, TX 77030, USA; Director, Clinical Cardiac Electrophysiology Fellowship Training Program, 6431 Fannin Street, Suite MSB 1.246, Houston, TX 77030, USA; Director, Cardiac Electrophysiology Laboratories-Memorial Hermann Hospital, 6431 Fannin Street, Suite MSB 1.246, Houston, TX 77030, USA.
Indian Heart J. 2013 Mar-Apr;65(2):229-31. doi: 10.1016/j.ihj.2013.02.003. Epub 2013 Feb 24.
A 68-year-old woman with a history of dilated non-ischemic cardiomyopathy presented with syncope. The index ECG showed sinus rhythm with left bundle branch block. On telemetry episodes of sinus rhythm with narrower QRS complexes conduced in 2:1 pattern were noted. Invasive electrophysiological study was performed to determine cause of syncope. Normal conduction up to the AV node with an AH interval of 79 ms (normal = 55-125 ms) was observed. However, every alternate sinus beat was blocked after the inscription of His deflection (infra-Hisian block). The narrow beats conducted through the His bundle with HV intervals of 54 ms (normal = 35-55 ms). When 1:1 conduction resumed further abnormality of the His-Purkinje conduction system became evident with a QRS morphology that of an LBBB and prolongation of HV interval (HV = 96 ms). Criteria to differentiate nodal versus infranodal block based on electrophysiological properties of the nodal and infranodal system are discussed.
一名有扩张型非缺血性心肌病病史的68岁女性出现晕厥。初始心电图显示窦性心律伴左束支传导阻滞。通过遥测发现存在窦性心律发作，较窄的QRS波群以2:1模式下传。进行了有创电生理研究以确定晕厥原因。观察到直至房室结传导正常，AH间期为79毫秒（正常范围 = 55 - 125毫秒）。然而，在希氏束电位记录后，每隔一次窦性搏动发生阻滞（希氏束下阻滞）。窄QRS波群通过希氏束下传，HV间期为54毫秒（正常范围 = 35 - 55毫秒）。当恢复1:1传导时，希氏 - 浦肯野传导系统进一步出现异常，表现为QRS形态呈左束支传导阻滞图形且HV间期延长（HV = 96毫秒）。讨论了基于结内和结下系统电生理特性区分结内与结下阻滞的标准。
