Department of Cardiology, Ascension St. Vincent Hospital, 8333 Naab Road, #400, Indianapolis 46260, IN, USA.
Europace. 2021 Apr 6;23(4):634-639. doi: 10.1093/europace/euaa283.
The response to premature atrial complexes (PACs) during tachycardia has been shown to differentiate atrioventricular nodal re-entrant tachycardia (AVNRT) from focal junctional tachycardia (JT). His refractory PAC (HrPACs) perturbing the next His (resetting with fusion) is diagnostic of AVNRT and such a late PAC fusing with the native beat cannot reset the focal source of JT. Early PAC advancing the immediate His with continuation of tachycardia suggests JT but can also occur in AVNRT due to simultaneous conduction through the AV nodal fast and slow pathways [two-for-one response (TFOR)]. The objective of this study was to evaluate the incidence and mechanism of TFOR after early premature atrial complexes (ePACs) during AVNRT and to differentiate it from the known response to ePACs during JT.
Typical AVNRT cases were diagnosed using standard criteria. We evaluated the responses to scanning PACs delivered during tachycardia in 100 patients undergoing AV node slow pathway modification for AVNRT. The responses to HrPACs and ePACs delivered from coronary sinus os or high right atrium were retrospectively reviewed. In 10 patients, ePACs advanced the immediate His with continuation of tachycardia. In all 10 cases, HrPACs advanced the next His, confirming AVNRT as the mechanism, and indicating a TFOR.
A TFOR can occur in a small number of patients during AVNRT and is therefore not diagnostic of JT. However, HrPACs always perturbed the next His in these cases, confirming the diagnosis of AVNRT and allowing for differentiation from JT.
已有研究表明，在心动过速时对房性期前收缩（PACs）的反应可将房室结折返性心动过速（AVNRT）与局灶性结折返性心动过速（JT）区分开来。His 不应期的房性期前收缩（HrPACs）扰乱下一个 His（融合后重置）即可诊断为 AVNRT，而这种晚期 PAC 与自身搏动融合则不能重置 JT 的局灶源。早期 PAC 提前激动即刻 His 并维持心动过速提示为 JT，但也可能因 AV 结快、慢径同时传导而发生在 AVNRT 中[二合一反应（TFOR）]。本研究旨在评估 AVNRT 中早期房性期前收缩（ePACs）后 TFOR 的发生率和机制，并将其与已知的 JT 中 ePACs 的反应区分开来。
采用标准标准诊断典型 AVNRT 病例。我们评估了 100 例接受 AV 结慢径改良的 AVNRT 患者在心动过速期间进行扫描 PACs 时的反应。回顾性分析冠状窦口或高位右心房发放的 HrPACs 和 ePACs 的反应。在 10 例患者中，ePACs 提前激动即刻 His 并维持心动过速。在所有 10 例中，HrPACs 提前激动下一个 His，证实为 AVNRT 机制，提示 TFOR。
TFOR 可在少数 AVNRT 患者中发生，因此不能诊断为 JT。然而，在这些情况下，HrPACs 总是扰乱下一个 His，这证实了 AVNRT 的诊断，并可与 JT 区分开来。
